Merge pull request #140 from snshn/cssparser

Switch to token-based CSS parser

.adr-dir

@@ -0,0 +1 @@
+docs/arch

.appveyor.yml

@@ -52,11 +52,11 @@ environment:
   # Nightly 64-bit MSVC
     - channel: nightly
       target: x86_64-pc-windows-msvc
-      #cargoflags: --features "unstable"
+      cargoflags: --features "unstable"
   # Nightly 32-bit MSVC
     - channel: nightly
       target: i686-pc-windows-msvc
-      #cargoflags: --features "unstable"
+      cargoflags: --features "unstable"
 
 ### GNU Toolchains ###
 
@@ -80,12 +80,12 @@ environment:
     - channel: nightly
       target: x86_64-pc-windows-gnu
       MINGW_PATH: 'C:\mingw-w64\x86_64-6.3.0-posix-seh-rt_v5-rev1\mingw64\bin'
-      #cargoflags: --features "unstable"
+      cargoflags: --features "unstable"
   # Nightly 32-bit GNU
     - channel: nightly
       target: i686-pc-windows-gnu
       MINGW_PATH: 'C:\MinGW\bin'
-      #cargoflags: --features "unstable"
+      cargoflags: --features "unstable"
 
 ### Allowed failures ###
 
@@ -95,6 +95,7 @@ environment:
 matrix:
   allow_failures:
     - channel: nightly
+    - channel: beta
 
 # If you only care about stable channel build failures, uncomment the following line:
     #- channel: beta
@@ -114,6 +115,7 @@ install:
   - if defined MINGW_PATH set PATH=%PATH%;%MINGW_PATH%
   - rustc -vV
   - cargo -vV
+  - rustup component add rustfmt
 
 ## Build Script ##
 
@@ -122,7 +124,8 @@ install:
 build: false
 
 # Uses 'cargo test' to run tests and build. Alternatively, the project may call compiled programs
-#directly or perform other testing commands. Rust will automatically be placed in the PATH
+# directly or perform other testing commands. Rust will automatically be placed in the PATH
 # environment variable.
 test_script:
-- cargo test --verbose %cargoflags%
+  - cargo build --all --locked --verbose %cargoflags%
+  - cargo test --all --locked --verbose %cargoflags%

.gitignore

@@ -2,9 +2,5 @@
 # will have compiled files and executables
 /target/
 
-# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
-# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
-Cargo.lock
-
 # These are backup files generated by rustfmt
 **/*.rs.bk

.travis.yml

@@ -1,17 +1,37 @@
 language: rust
 cache: cargo
 
-sudo: false
-
 os:
-    - linux
-    - osx
+- linux
+- osx
+- windows
 
 rust:
-    - stable
-    - beta 
-    - nightly
+- stable
+- beta
+- nightly
+
+git:
+  autocrlf: false # don't mangle LF into CRLF on windows
+
+before_script:
+- rustup component add rustfmt
 
 script:
-    - cargo build --verbose
-    - cargo test --verbose
+- cargo build --all --locked --verbose
+- cargo test --all --locked --verbose
+- |
+  if [[ "$TRAVIS_RUST_VERSION" == "stable" ]]; then
+    cargo fmt --all -- --check
+  fi
+
+after_success: |
+  if [ "${TRAVIS_OS_NAME}" == linux ] && [ "${TRAVIS_RUST_VERSION}" == stable ]; then
+    docker build -t monolith .
+    docker run monolith monolith -V
+  fi
+
+jobs:
+  allow_failures:
+  - rust: nightly
+  fast_finish: true

Cargo.toml

@@ -1,18 +1,28 @@
 [package]
 name = "monolith"
-version = "2.0.16"
+version = "2.2.1"
+edition = "2018"
 authors = [
     "Sunshine <sunshine@uberspace.net>",
     "Mahdi Robatipoor <mahdi.robatipoor@gmail.com>",
+    "Emmanuel Delaborde <th3rac25@gmail.com>",
+    "Emi Simpson <emi@alchemi.dev>",
+    "rhysd <lin90162@yahoo.co.jp>",
 ]
 description = "CLI tool for saving web pages as a single HTML file"
 
 [dependencies]
-base64 = "0.10.1"
+base64 = "0.11.0"
 clap = "2.33.0"
-html5ever = "0.24.0"
-indicatif = "0.11.0"
-lazy_static = "1.3.0"
-regex = "1.2.1"
-reqwest = "0.9.20"
-url = "2.1.0"
+cssparser = "0.27.2"
+html5ever = "0.24.1"
+url = "2.1.1"
+
+[dependencies.reqwest]
+version = "0.10.*"
+default-features = false
+features = ["default-tls", "blocking", "gzip"]
+
+[dev-dependencies]
+assert_cmd = "0.12.0"
+tempfile = "3.1.0"

Dockerfile

@@ -0,0 +1,18 @@
+FROM rust
+
+WORKDIR /usr/local/src/
+RUN curl -s https://api.github.com/repos/y2z/monolith/releases/latest \
+| grep "tarball_url.*\"," \
+| cut -d '"' -f 4 \
+| wget -qi - -O monolith.tar.gz
+
+RUN tar xfz monolith.tar.gz \
+&& mv Y2Z-monolith-* monolith \
+&& rm monolith.tar.gz
+
+WORKDIR /usr/local/src/monolith
+RUN ls -a
+RUN make install
+
+WORKDIR /tmp
+CMD ["/usr/local/cargo/bin/monolith"]

Makefile

@@ -0,0 +1,21 @@
+#!/usr/bin/make -f
+
+all: test
+.PHONY: all
+
+build:
+	@cargo build --locked
+.PHONY: build
+
+install:
+	@cargo install --force --locked --path .
+.PHONY: install
+
+test: build
+	@cargo test --locked
+	@cargo fmt --all -- --check
+.PHONY: test
+
+lint:
+	@cargo fmt --all --
+.PHONY: lint

README.md

@@ -1,34 +1,82 @@
 [![Travis CI Build Status](https://travis-ci.org/Y2Z/monolith.svg?branch=master)](https://travis-ci.org/Y2Z/monolith)
-[![AppVeyor Build status](https://ci.appveyor.com/api/projects/status/j1v1d96sw952b1ch?svg=true)](https://ci.appveyor.com/project/vflyson/monolith)
+[![AppVeyor Build status](https://ci.appveyor.com/api/projects/status/ae7soyjih8jg2bv7/branch/master?svg=true)](https://ci.appveyor.com/project/snshn/monolith/branch/master)
 
-# monolith
+```
+ ___     ___________    __________      ___________________    ___
+|   \   /           \  |          |    |                   |  |   |
+|    \_/     __      \_|    __    |    |    ___     ___    |__|   |
+|           |  |           |  |   |    |   |   |   |   |          |
+|           |__|    _      |__|   |____|   |   |   |   |    __    |
+|   |\_/|          | \                     |   |   |   |   |  |   |
+|___|   |__________|  \____________________|   |___|   |___|  |___|
+```
 
-A data hoarder's dream come true: bundle any web page into a single HTML file.  
-You can finally replace that gazillion of open tabs with a gazillion of .html files stored somewhere on your precious little drive.
+A data hoarder's dream come true: bundle any web page into a single HTML file. You can finally replace that gazillion of open tabs with a gazillion of .html files stored somewhere on your precious little drive.
 
 Unlike the conventional "Save page as", `monolith` not only saves the target document, it embeds CSS, image, and JavaScript assets **all at once**, producing a single HTML5 document that is a joy to store and share.
 
 If compared to saving websites with `wget -mpk`, this tool embeds all assets as data URLs and therefore lets browsers render the saved page exactly the way it was on the Internet, even when no network connection is available.
 
-<!-- `This program works both on remote and local targets. -->
+---------------------------------------------------
 
-### Installation
+## Installation
+
+#### From source
     $ git clone https://github.com/Y2Z/monolith.git
     $ cd monolith
-    $ cargo install --path .
+    $ make install
 
-### Usage
-    $ monolith https://lyrics.github.io/db/p/portishead/dummy/roads/ > portishead-roads-lyrics.html
+#### With Homebrew (on macOS and GNU/Linux)
+    $ brew install monolith
 
-### Options
+#### Using Snapcraft (on GNU/Linux)
+    $ snap install monolith
+
+#### Via Docker
+The guide can be found [here](docs/containers.md)
+
+---------------------------------------------------
+
+## Usage
+    $ monolith https://lyrics.github.io/db/P/Portishead/Dummy/Roads/ -o portishead-roads-lyrics.html
+
+---------------------------------------------------
+
+## Options
+ - `-c`: Ignore styles
+ - `-f`: Exclude frames and iframes
  - `-i`: Remove images
+ - `-I`: Isolate the document
  - `-j`: Exclude JavaScript
  - `-k`: Accept invalid X.509 (TLS) certificates
+ - `-o`: Write output to file
  - `-s`: Silent mode
- - `-u`: Specify custom User-Agent
+ - `-t`: Set custom network request timeout
+ - `-u`: Provide own User-Agent
 
-### License
+---------------------------------------------------
+
+## HTTPS and HTTP proxies
+Please set `https_proxy`, `http_proxy`, and `no_proxy` environment variables.
+
+---------------------------------------------------
+
+## Contributing
+Please open an issue if something is wrong, that helps make this project better.
+
+---------------------------------------------------
+
+## Related projects
+ - `Monolith Chrome Extension`: https://github.com/rhysd/monolith-of-web
+ - `Pagesaver`: https://github.com/distributed-mind/pagesaver
+ - `Personal WayBack Machine`: https://github.com/popey/pwbm
+
+---------------------------------------------------
+
+## License
 The Unlicense
 
+---------------------------------------------------
+
 <!-- Microtext -->
 <sub>Keep in mind that `monolith` is not aware of your browser's session</sub>

docs/arch/0001-record-architecture-decisions.md

@@ -0,0 +1,19 @@
+# 1. Record architecture decisions
+
+Date: 2019-12-25
+
+## Status
+
+Accepted
+
+## Context
+
+We need to record the architectural decisions made on this project.
+
+## Decision
+
+We will use Architecture Decision Records, as [described by Michael Nygard](http://thinkrelevance.com/blog/2011/11/15/documenting-architecture-decisions).
+
+## Consequences
+
+See Michael Nygard's article, linked above. For a lightweight ADR toolset, see Nat Pryce's [adr-tools](https://github.com/npryce/adr-tools).

docs/arch/0003-network-request-timeout.md

@@ -0,0 +1,25 @@
+# 2. Network request timeout
+
+Date: 2020-02-15
+
+## Status
+
+Accepted
+
+## Context
+
+A slow network connection and overloaded server may negatively impact network response time.
+
+## Decision
+
+Make the program simulate behavior of popular web browsers and CLI tools, where 
+the default network response timeout is most often set to 120 seconds.
+
+Instead of featuring retries for timed out network requests, the program
+should have an option to adjust the timeout length, along with making it
+indefinite when given "0" as its value.
+
+## Consequences
+
+The user is able to retrieve resources that have long response time, as well as obtain
+full control over how soon, and if at all, network requests should time out.

docs/arch/0005-asset-minimization.md

@@ -0,0 +1,25 @@
+# 4. Asset Minimization
+
+Date: 2020-03-14
+
+## Status
+
+Accepted
+
+## Context
+
+It may look like a good idea to make monolith compress retrieved assets while
+saving the page for the purpose of reducing the resulting document's file size.
+
+## Decision
+
+Given that the main purpose of this program is to save pages in a convenient to store and share manner — it's mostly an archiving tool,
+aside from being able to tell monolith to exclude certain types of asests (e.g. images, CSS, JavaScript),
+it would be outside of scope of this program to implement code for compressing assets. Minimizing files before embedding them
+does not reduce the amount of data that needs to be transferred either. A separate tool can be used later to compress and minimize pages
+saved by monolith, if needed.
+
+## Consequences
+
+Monolith will not support modification of original document assets for the purpose of reducing their size, sticking to performing only a minimal
+amount of modifications to the original web page — whatever is needed to provide security or exclude unwanted asset types.

docs/containers.md

@@ -0,0 +1,15 @@
+1. Run `docker build -t y2z/monolith .` to create a Docker image
+
+2. Create a file named `monolith` which contains:
+```sh
+#!/bin/sh
+
+docker run --rm \
+    y2z/monolith \
+    monolith \
+    "$@"
+```
+3. Make the file executable (`chmod +x monolith`) and include it into your `$PATH`
+4. Now you should be able to run a containerized build of monolith like this:  
+`monolith -I https://github.com > document.html`
+

snap/snapcraft.yaml

@@ -1,6 +1,7 @@
 name: monolith
 base: core18 
-version: git
+# Version data defined inside the monolith part below
+adopt-info: monolith
 summary: Monolith - Save HTML pages with ease 
 description: |
   A data hoarder's dream come true: bundle any web page into a single
@@ -17,6 +18,14 @@ description: |
 
 confinement: strict
 
+# Building on armhf fails, so we specify all supported non-armhf architectures
+architectures:
+  - build-on: amd64
+  - build-on: i386
+  - build-on: arm64
+  - build-on: ppc64el
+  - build-on: s390x
+
 parts:
   monolith:
     plugin: rust
@@ -24,6 +33,21 @@ parts:
     build-packages:
       - libssl-dev
       - pkg-config
+    override-pull: |
+      snapcraftctl pull
+      # Determine the current tag
+      last_committed_tag="$(git describe --tags --abbrev=0)"
+      last_committed_tag_ver="$(echo ${last_committed_tag} | sed 's/v//')"
+      # Determine the most recent version in the beta channel in the Snap Store
+      last_released_tag="$(snap info $SNAPCRAFT_PROJECT_NAME | awk '$1 == "beta:" { print $2 }')"
+      # If the latest tag from the upstream project has not been released to
+      # beta, build that tag instead of master.
+      if [ "${last_committed_tag_ver}" != "${last_released_tag}" ]; then
+        git fetch
+        git checkout "${last_committed_tag}"
+      fi
+      # set version number of the snap based on what we did above
+      snapcraftctl set-version $(git describe --tags --abbrev=0)
 
 apps:
   monolith:

src/args.rs

@@ -0,0 +1,73 @@
+use clap::{App, Arg};
+
+#[derive(Default)]
+pub struct AppArgs {
+    pub url_target: String,
+    pub no_css: bool,
+    pub no_frames: bool,
+    pub no_images: bool,
+    pub no_js: bool,
+    pub insecure: bool,
+    pub isolate: bool,
+    pub output: String,
+    pub silent: bool,
+    pub timeout: u64,
+    pub user_agent: String,
+}
+
+const DEFAULT_NETWORK_TIMEOUT: u64 = 120;
+const DEFAULT_USER_AGENT: &str =
+    "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:73.0) Gecko/20100101 Firefox/73.0";
+
+impl AppArgs {
+    pub fn get() -> AppArgs {
+        let app = App::new(env!("CARGO_PKG_NAME"))
+            .version(crate_version!())
+            .author(crate_authors!("\n"))
+            .about(crate_description!())
+            .arg(
+                Arg::with_name("url")
+                    .required(true)
+                    .takes_value(true)
+                    .index(1)
+                    .help("URL to download"),
+            )
+            // .args_from_usage("-a, --include-audio 'Removes audio sources'")
+            .args_from_usage("-c, --no-css 'Removes CSS'")
+            .args_from_usage("-f, --no-frames 'Removes frames and iframes'")
+            .args_from_usage("-i, --no-images 'Removes images'")
+            .args_from_usage("-I, --isolate 'Cuts off document from the Internet'")
+            .args_from_usage("-j, --no-js 'Removes JavaScript'")
+            .args_from_usage("-k, --insecure 'Allows invalid X.509 (TLS) certificates'")
+            .args_from_usage("-o, --output=[document.html] 'Writes output to <file>'")
+            .args_from_usage("-s, --silent 'Suppresses verbosity'")
+            .args_from_usage("-t, --timeout=[60] 'Adjusts network request timeout'")
+            .args_from_usage("-u, --user-agent=[Firefox] 'Sets custom User-Agent string'")
+            // .args_from_usage("-v, --include-video 'Removes video sources'")
+            .get_matches();
+        let mut app_args = AppArgs::default();
+        // Process the command
+        app_args.url_target = app
+            .value_of("url")
+            .expect("please set target url")
+            .to_string();
+        app_args.no_css = app.is_present("no-css");
+        app_args.no_frames = app.is_present("no-frames");
+        app_args.no_images = app.is_present("no-images");
+        app_args.no_js = app.is_present("no-js");
+        app_args.insecure = app.is_present("insecure");
+        app_args.isolate = app.is_present("isolate");
+        app_args.silent = app.is_present("silent");
+        app_args.timeout = app
+            .value_of("timeout")
+            .unwrap_or(&DEFAULT_NETWORK_TIMEOUT.to_string())
+            .parse::<u64>()
+            .unwrap();
+        app_args.output = app.value_of("output").unwrap_or("").to_string();
+        app_args.user_agent = app
+            .value_of("user-agent")
+            .unwrap_or(DEFAULT_USER_AGENT)
+            .to_string();
+        app_args
+    }
+}

src/css.rs

@@ -0,0 +1,370 @@
+use cssparser::{ParseError, Parser, ParserInput, SourcePosition, Token};
+use reqwest::blocking::Client;
+use std::collections::HashMap;
+
+use crate::utils::{data_to_data_url, decode_url, get_url_fragment, resolve_url, retrieve_asset};
+
+const CSS_PROPS_WITH_IMAGE_URLS: &[&str] = &[
+    "background",
+    "background-image",
+    "border",
+    "border-image",
+    "border-image-source",
+    "content",
+    "cursor",
+    "list-style",
+    "list-style-image",
+    "mask",
+    "mask-image",
+];
+
+const TRANSPARENT_PIXEL: &str = "data:image/png;base64,\
+     iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=";
+
+pub fn is_image_url_prop(prop_name: &str) -> bool {
+    CSS_PROPS_WITH_IMAGE_URLS
+        .iter()
+        .find(|p| prop_name.eq_ignore_ascii_case(p))
+        .is_some()
+}
+
+pub fn enquote(input: String, double: bool) -> String {
+    if double {
+        format!("\"{}\"", input.replace("\"", "\\\""))
+    } else {
+        format!("'{}'", input.replace("'", "\\'"))
+    }
+}
+
+pub fn process_css<'a>(
+    cache: &mut HashMap<String, String>,
+    client: &Client,
+    parent_url: &str,
+    parser: &mut Parser,
+    rule_name: &str,
+    prop_name: &str,
+    func_name: &str,
+    opt_no_images: bool,
+    opt_silent: bool,
+) -> Result<String, ParseError<'a, String>> {
+    let mut result: String = str!();
+
+    let mut curr_rule: String = str!(rule_name.clone());
+    let mut curr_prop: String = str!(prop_name.clone());
+    let mut token: &Token;
+    let mut token_offset: SourcePosition;
+
+    loop {
+        token_offset = parser.position();
+        token = match parser.next_including_whitespace_and_comments() {
+            Ok(token) => token,
+            Err(_) => {
+                break;
+            }
+        };
+
+        match *token {
+            Token::Comment(_) => {
+                let token_slice = parser.slice_from(token_offset);
+                result.push_str(str!(token_slice).as_str());
+            }
+            Token::Semicolon => result.push_str(";"),
+            Token::Colon => result.push_str(":"),
+            Token::Comma => result.push_str(","),
+            Token::ParenthesisBlock | Token::SquareBracketBlock | Token::CurlyBracketBlock => {
+                let closure: &str;
+                if token == &Token::ParenthesisBlock {
+                    result.push_str("(");
+                    closure = ")";
+                } else if token == &Token::SquareBracketBlock {
+                    result.push_str("[");
+                    closure = "]";
+                } else {
+                    result.push_str("{");
+                    closure = "}";
+                }
+
+                let block_css: String = parser
+                    .parse_nested_block(|parser| {
+                        process_css(
+                            cache,
+                            client,
+                            parent_url,
+                            parser,
+                            rule_name,
+                            curr_prop.as_str(),
+                            func_name,
+                            opt_no_images,
+                            opt_silent,
+                        )
+                    })
+                    .unwrap();
+                result.push_str(block_css.as_str());
+
+                result.push_str(closure);
+            }
+            Token::CloseParenthesis => result.push_str(")"),
+            Token::CloseSquareBracket => result.push_str("]"),
+            Token::CloseCurlyBracket => result.push_str("}"),
+            Token::IncludeMatch => result.push_str("~="),
+            Token::DashMatch => result.push_str("|="),
+            Token::PrefixMatch => result.push_str("^="),
+            Token::SuffixMatch => result.push_str("$="),
+            Token::SubstringMatch => result.push_str("*="),
+            Token::CDO => result.push_str("<!--"),
+            Token::CDC => result.push_str("-->"),
+            Token::WhiteSpace(ref value) => {
+                result.push_str(value);
+            }
+            Token::Ident(ref value) => {
+                curr_prop = str!(value);
+                result.push_str(value);
+            }
+            Token::AtKeyword(ref value) => {
+                curr_rule = str!(value);
+                result.push_str("@");
+                result.push_str(value);
+            }
+            Token::Hash(ref value) => {
+                result.push_str("#");
+                result.push_str(value);
+            }
+            Token::QuotedString(ref value) => {
+                let is_import: bool = curr_rule == "import";
+                if is_import {
+                    // Reset current at-rule value
+                    curr_rule = str!();
+                }
+
+                if is_import {
+                    // Skip empty import values
+                    if value.len() < 1 {
+                        result.push_str("''");
+                        continue;
+                    }
+
+                    let full_url = resolve_url(&parent_url, value).unwrap_or_default();
+                    let url_fragment = get_url_fragment(full_url.clone());
+                    let full_url_decoded = decode_url(full_url);
+                    let (css, final_url) = retrieve_asset(
+                        cache,
+                        client,
+                        &parent_url,
+                        &full_url_decoded,
+                        false,
+                        "",
+                        opt_silent,
+                    )
+                    .unwrap_or_default();
+
+                    result.push_str(
+                        enquote(
+                            data_to_data_url(
+                                "text/css",
+                                embed_css(
+                                    cache,
+                                    client,
+                                    final_url.as_str(),
+                                    &css,
+                                    opt_no_images,
+                                    opt_silent,
+                                )
+                                .as_bytes(),
+                                &final_url,
+                                url_fragment.as_str(),
+                            ),
+                            false,
+                        )
+                        .as_str(),
+                    );
+                } else {
+                    if func_name == "url" {
+                        // Skip empty url()'s
+                        if value.len() < 1 {
+                            continue;
+                        }
+
+                        if opt_no_images && is_image_url_prop(curr_prop.as_str()) {
+                            result.push_str(enquote(str!(TRANSPARENT_PIXEL), false).as_str());
+                        } else {
+                            let resolved_url = resolve_url(&parent_url, value).unwrap_or_default();
+                            let (data_url, _final_url) = retrieve_asset(
+                                cache,
+                                client,
+                                &parent_url,
+                                &resolved_url,
+                                true,
+                                "",
+                                opt_silent,
+                            )
+                            .unwrap_or_default();
+                            result.push_str(enquote(data_url, false).as_str());
+                        }
+                    } else {
+                        result.push_str(enquote(str!(value), false).as_str());
+                    }
+                }
+            }
+            Token::Number {
+                ref has_sign,
+                ref value,
+                ..
+            } => {
+                if *has_sign && *value >= 0. {
+                    result.push_str("+");
+                }
+                result.push_str(&value.to_string())
+            }
+            Token::Percentage {
+                ref has_sign,
+                ref unit_value,
+                ..
+            } => {
+                if *has_sign {
+                    result.push_str("-");
+                }
+                result.push_str(str!(unit_value * 100.).as_str());
+                result.push_str("%");
+            }
+            Token::Dimension {
+                ref value,
+                ref unit,
+                ..
+            } => {
+                result.push_str(str!(value).as_str());
+                result.push_str(str!(unit).as_str());
+            }
+            Token::IDHash(ref value) => {
+                result.push_str("#");
+                result.push_str(value);
+            }
+            Token::UnquotedUrl(ref value) => {
+                let is_import: bool = curr_rule == "import";
+                if is_import {
+                    // Reset current at-rule value
+                    curr_rule = str!();
+                }
+
+                // Skip empty url()'s
+                if value.len() < 1 {
+                    result.push_str("url()");
+                    continue;
+                } else if value.starts_with("#") {
+                    result.push_str("url(");
+                    result.push_str(value);
+                    result.push_str(")");
+                    continue;
+                }
+
+                result.push_str("url(");
+                if is_import {
+                    let full_url = resolve_url(&parent_url, value).unwrap_or_default();
+                    let url_fragment = get_url_fragment(full_url.clone());
+                    let full_url_decoded = decode_url(full_url);
+                    let (css, final_url) = retrieve_asset(
+                        cache,
+                        client,
+                        &parent_url,
+                        &full_url_decoded,
+                        false,
+                        "",
+                        opt_silent,
+                    )
+                    .unwrap_or_default();
+
+                    result.push_str(
+                        enquote(
+                            data_to_data_url(
+                                "text/css",
+                                embed_css(
+                                    cache,
+                                    client,
+                                    final_url.as_str(),
+                                    &css,
+                                    opt_no_images,
+                                    opt_silent,
+                                )
+                                .as_bytes(),
+                                &final_url,
+                                url_fragment.as_str(),
+                            ),
+                            false,
+                        )
+                        .as_str(),
+                    );
+                } else {
+                    if opt_no_images && is_image_url_prop(curr_prop.as_str()) {
+                        result.push_str(enquote(str!(TRANSPARENT_PIXEL), false).as_str());
+                    } else {
+                        let full_url = resolve_url(&parent_url, value).unwrap_or_default();
+                        let (data_url, _final_url) = retrieve_asset(
+                            cache,
+                            client,
+                            &parent_url,
+                            &full_url,
+                            true,
+                            "",
+                            opt_silent,
+                        )
+                        .unwrap_or_default();
+                        result.push_str(enquote(data_url, false).as_str());
+                    }
+                }
+                result.push_str(")");
+            }
+            Token::Delim(ref value) => result.push_str(&value.to_string()),
+            Token::Function(ref name) => {
+                let function_name: &str = &name.clone();
+                result.push_str(function_name);
+                result.push_str("(");
+
+                let block_css: String = parser
+                    .parse_nested_block(|parser| {
+                        process_css(
+                            cache,
+                            client,
+                            parent_url,
+                            parser,
+                            curr_rule.as_str(),
+                            curr_prop.as_str(),
+                            function_name,
+                            opt_no_images,
+                            opt_silent,
+                        )
+                    })
+                    .unwrap();
+                result.push_str(block_css.as_str());
+
+                result.push_str(")");
+            }
+            Token::BadUrl(_) | Token::BadString(_) => {}
+        }
+    }
+
+    Ok(result)
+}
+
+pub fn embed_css(
+    cache: &mut HashMap<String, String>,
+    client: &Client,
+    parent_url: &str,
+    css: &str,
+    opt_no_images: bool,
+    opt_silent: bool,
+) -> String {
+    let mut input = ParserInput::new(&css);
+    let mut parser = Parser::new(&mut input);
+
+    process_css(
+        cache,
+        client,
+        parent_url,
+        &mut parser,
+        "",
+        "",
+        "",
+        opt_no_images,
+        opt_silent,
+    )
+    .unwrap()
+}

src/http.rs

@@ -1,179 +0,0 @@
-use regex::Regex;
-use reqwest::Client;
-use reqwest::header::{CONTENT_TYPE, USER_AGENT};
-use std::time::Duration;
-use url::{ParseError, Url};
-use utils::data_to_dataurl;
-
-lazy_static! {
-    static ref REGEX_URL: Regex = Regex::new(r"^https?://").unwrap();
-}
-
-pub fn is_data_url(url: &str) -> Result<bool, ParseError> {
-    match Url::parse(url) {
-        Ok(parsed_url) => Ok(parsed_url.scheme() == "data"),
-        Err(err) => Err(err),
-    }
-}
-
-pub fn is_valid_url(path: &str) -> bool {
-    REGEX_URL.is_match(path)
-}
-
-pub fn resolve_url(from: &str, to: &str) -> Result<String, ParseError> {
-    let result = if is_valid_url(to) {
-        // (anything, http://site.com/css/main.css)
-        to.to_string()
-    } else {
-        Url::parse(from)?.join(to)?.to_string()
-    };
-
-    Ok(result)
-}
-
-pub fn retrieve_asset(
-    url: &str,
-    as_dataurl: bool,
-    as_mime: &str,
-    opt_user_agent: &str,
-    opt_silent: bool,
-    opt_insecure: bool,
-) -> Result<String, reqwest::Error> {
-    if is_data_url(&url).unwrap() {
-        Ok(url.to_string())
-    } else {
-        let client = Client::builder()
-            .timeout(Duration::from_secs(10))
-            .danger_accept_invalid_certs(opt_insecure)
-            .build()?;
-        let mut response = client
-            .get(url)
-            .header(USER_AGENT, opt_user_agent)
-            .send()?;
-        let final_url = response.url().as_str();
-
-        if !opt_silent {
-            if url == final_url {
-                eprintln!("[ {} ]", &url);
-            } else {
-                eprintln!("[ {} -> {} ]", &url, &final_url);
-            }
-        }
-
-        if as_dataurl {
-            // Convert response into a byte array
-            let mut data: Vec<u8> = vec![];
-            response.copy_to(&mut data)?;
-
-            // Attempt to obtain MIME type by reading the Content-Type header
-            let mimetype = if as_mime == "" {
-                response
-                    .headers()
-                    .get(CONTENT_TYPE)
-                    .and_then(|header| header.to_str().ok())
-                    .unwrap_or(&as_mime)
-            } else {
-                as_mime
-            };
-
-            Ok(data_to_dataurl(&mimetype, &data))
-        } else {
-            Ok(response.text().unwrap())
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_is_valid_url() {
-        assert!(is_valid_url("https://www.rust-lang.org/"));
-        assert!(is_valid_url("http://kernel.org"));
-        assert!(!is_valid_url("./index.html"));
-        assert!(!is_valid_url("some-local-page.htm"));
-        assert!(!is_valid_url("ftp://1.2.3.4/www/index.html"));
-        assert!(!is_valid_url(
-            "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
-        ));
-    }
-
-    #[test]
-    fn test_resolve_url() -> Result<(), ParseError> {
-        let resolved_url = resolve_url(
-            "https://www.kernel.org",
-            "../category/signatures.html",
-        )?;
-        assert_eq!(
-            resolved_url.as_str(),
-            "https://www.kernel.org/category/signatures.html"
-        );
-
-        let resolved_url = resolve_url(
-            "https://www.kernel.org",
-            "category/signatures.html",
-        )?;
-        assert_eq!(
-            resolved_url.as_str(),
-            "https://www.kernel.org/category/signatures.html"
-        );
-
-        let resolved_url = resolve_url(
-            "saved_page.htm",
-            "https://www.kernel.org/category/signatures.html",
-        )?;
-        assert_eq!(
-            resolved_url.as_str(),
-            "https://www.kernel.org/category/signatures.html"
-        );
-
-        let resolved_url = resolve_url(
-            "https://www.kernel.org",
-            "//www.kernel.org/theme/images/logos/tux.png",
-        )?;
-        assert_eq!(
-            resolved_url.as_str(),
-            "https://www.kernel.org/theme/images/logos/tux.png"
-        );
-
-        let resolved_url = resolve_url(
-            "https://www.kernel.org",
-            "//another-host.org/theme/images/logos/tux.png",
-        )?;
-        assert_eq!(
-            resolved_url.as_str(),
-            "https://another-host.org/theme/images/logos/tux.png"
-        );
-
-        let resolved_url = resolve_url(
-            "https://www.kernel.org/category/signatures.html",
-            "/theme/images/logos/tux.png",
-        )?;
-        assert_eq!(
-            resolved_url.as_str(),
-            "https://www.kernel.org/theme/images/logos/tux.png"
-        );
-
-        let resolved_url = resolve_url(
-            "https://www.w3schools.com/html/html_iframe.asp",
-            "default.asp",
-        )?;
-        assert_eq!(
-            resolved_url.as_str(),
-            "https://www.w3schools.com/html/default.asp"
-        );
-
-        Ok(())
-    }
-
-    #[test]
-    fn test_is_data_url() {
-        assert!(
-            is_data_url("data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h")
-                .unwrap_or(false)
-        );
-        assert!(!is_data_url("https://kernel.org").unwrap_or(false));
-        assert!(!is_data_url("//kernel.org").unwrap_or(false));
-    }
-}

src/js.rs

@@ -0,0 +1,103 @@
+const JS_DOM_EVENT_ATTRS: &[&str] = &[
+    // From WHATWG HTML spec 8.1.5.2 "Event handlers on elements, Document objects, and Window objects":
+    //   https://html.spec.whatwg.org/#event-handlers-on-elements,-document-objects,-and-window-objects
+    //   https://html.spec.whatwg.org/#attributes-3 (table "List of event handler content attributes")
+
+    // Global event handlers
+    "onabort",
+    "onauxclick",
+    "onblur",
+    "oncancel",
+    "oncanplay",
+    "oncanplaythrough",
+    "onchange",
+    "onclick",
+    "onclose",
+    "oncontextmenu",
+    "oncuechange",
+    "ondblclick",
+    "ondrag",
+    "ondragend",
+    "ondragenter",
+    "ondragexit",
+    "ondragleave",
+    "ondragover",
+    "ondragstart",
+    "ondrop",
+    "ondurationchange",
+    "onemptied",
+    "onended",
+    "onerror",
+    "onfocus",
+    "onformdata",
+    "oninput",
+    "oninvalid",
+    "onkeydown",
+    "onkeypress",
+    "onkeyup",
+    "onload",
+    "onloadeddata",
+    "onloadedmetadata",
+    "onloadstart",
+    "onmousedown",
+    "onmouseenter",
+    "onmouseleave",
+    "onmousemove",
+    "onmouseout",
+    "onmouseover",
+    "onmouseup",
+    "onwheel",
+    "onpause",
+    "onplay",
+    "onplaying",
+    "onprogress",
+    "onratechange",
+    "onreset",
+    "onresize",
+    "onscroll",
+    "onsecuritypolicyviolation",
+    "onseeked",
+    "onseeking",
+    "onselect",
+    "onslotchange",
+    "onstalled",
+    "onsubmit",
+    "onsuspend",
+    "ontimeupdate",
+    "ontoggle",
+    "onvolumechange",
+    "onwaiting",
+    "onwebkitanimationend",
+    "onwebkitanimationiteration",
+    "onwebkitanimationstart",
+    "onwebkittransitionend",
+    // Event handlers for <body/> and <frameset/> elements
+    "onafterprint",
+    "onbeforeprint",
+    "onbeforeunload",
+    "onhashchange",
+    "onlanguagechange",
+    "onmessage",
+    "onmessageerror",
+    "onoffline",
+    "ononline",
+    "onpagehide",
+    "onpageshow",
+    "onpopstate",
+    "onrejectionhandled",
+    "onstorage",
+    "onunhandledrejection",
+    "onunload",
+    // Event handlers for <html/> element
+    "oncut",
+    "oncopy",
+    "onpaste",
+];
+
+// Returns true if DOM attribute name matches a native JavaScript event handler
+pub fn attr_is_event_handler(attr_name: &str) -> bool {
+    JS_DOM_EVENT_ATTRS
+        .iter()
+        .find(|a| attr_name.eq_ignore_ascii_case(a))
+        .is_some()
+}

src/lib.rs

@@ -1,10 +1,10 @@
 #[macro_use]
-extern crate lazy_static;
-extern crate html5ever;
-extern crate regex;
-extern crate reqwest;
-extern crate url;
+mod macros;
 
+pub mod css;
 pub mod html;
-pub mod http;
+pub mod js;
 pub mod utils;
+
+#[cfg(test)]
+pub mod tests;

src/macros.rs

@@ -0,0 +1,9 @@
+#[macro_export]
+macro_rules! str {
+    () => {
+        String::new()
+    };
+    ($val: expr) => {
+        ToString::to_string(&$val)
+    };
+}

src/main.rs

@@ -1,63 +1,160 @@
+use monolith::html::{html_to_dom, stringify_document, walk_and_embed_assets};
+use monolith::utils::{data_url_to_text, is_data_url, is_file_url, is_http_url, retrieve_asset};
+use reqwest::blocking::Client;
+use reqwest::header::{HeaderMap, HeaderValue, USER_AGENT};
+use std::collections::HashMap;
+use std::env;
+use std::fs;
+use std::io::{self, Error, Write};
+use std::path::Path;
+use std::process;
+use std::time::Duration;
+
+mod args;
+mod macros;
+
 #[macro_use]
 extern crate clap;
-extern crate monolith;
+use crate::args::AppArgs;
 
-use clap::{App, Arg};
-use monolith::html::{html_to_dom, print_dom, walk_and_embed_assets};
-use monolith::http::{is_valid_url, retrieve_asset};
+enum Output {
+    Stdout(io::Stdout),
+    File(fs::File),
+}
 
-static DEFAULT_USER_AGENT: &str =
-    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:66.0) Gecko/20100101 Firefox/66.0";
+impl Output {
+    fn new(file_path: &str) -> Result<Output, Error> {
+        if file_path.is_empty() {
+            Ok(Output::Stdout(io::stdout()))
+        } else {
+            Ok(Output::File(fs::File::create(file_path)?))
+        }
+    }
 
-fn main() {
-    let command = App::new("monolith")
-        .version(crate_version!())
-        .author(crate_authors!("\n"))
-        .about(crate_description!())
-        .arg(
-            Arg::with_name("url")
-                .required(true)
-                .takes_value(true)
-                .index(1)
-                .help("URL to download"),
-        )
-        .args_from_usage("-i, --no-images 'Removes images'")
-        .args_from_usage("-j, --no-js 'Excludes JavaScript'")
-        .args_from_usage("-k, --insecure 'Accept invalid X.509 (TLS) certificates'")
-        .args_from_usage("-s, --silent 'Suppress verbosity'")
-        .args_from_usage("-u, --user-agent=[Iceweasel] 'Custom User-Agent string'")
-        .get_matches();
-
-    // Process the command
-    let arg_target = command.value_of("url").unwrap();
-    let opt_no_images = command.is_present("no-images");
-    let opt_no_js = command.is_present("no-js");
-    let opt_insecure = command.is_present("insecure");
-    let opt_silent = command.is_present("silent");
-    let opt_user_agent = command.value_of("user-agent").unwrap_or(DEFAULT_USER_AGENT);
-
-    if is_valid_url(arg_target) {
-        let data = retrieve_asset(
-                &arg_target,
-                false,
-                "",
-                opt_user_agent,
-                opt_silent,
-                opt_insecure,
-            ).unwrap();
-        let dom = html_to_dom(&data);
-
-        walk_and_embed_assets(
-            &arg_target,
-            &dom.document,
-            opt_no_js,
-            opt_no_images,
-            opt_user_agent,
-            opt_silent,
-            opt_insecure,
-        );
-
-        print_dom(&dom.document);
-        println!(); // Ensure newline at end of output
+    fn writeln_str(&mut self, s: &str) -> Result<(), Error> {
+        match self {
+            Output::Stdout(stdout) => {
+                writeln!(stdout, "{}", s)?;
+                stdout.flush()
+            }
+            Output::File(f) => {
+                writeln!(f, "{}", s)?;
+                f.flush()
+            }
+        }
     }
 }
+
+fn main() {
+    let app_args = AppArgs::get();
+    let original_target: &str = &app_args.url_target;
+    let target_url: &str;
+    let base_url;
+    let dom;
+
+    // Pre-process the input
+    let cwd_normalized: String =
+        str!(env::current_dir().unwrap().to_str().unwrap()).replace("\\", "/");
+    let path = Path::new(original_target);
+    let mut target: String = str!(original_target.clone()).replace("\\", "/");
+    let path_is_relative: bool = path.is_relative();
+
+    if target.clone().len() == 0 {
+        eprintln!("No target specified");
+        process::exit(1);
+    } else if is_http_url(target.clone()) || is_data_url(target.clone()) {
+        target_url = target.as_str();
+    } else if is_file_url(target.clone()) {
+        target_url = target.as_str();
+    } else if path.exists() {
+        if !path.is_file() {
+            eprintln!("Local target is not a file: {}", original_target);
+            process::exit(1);
+        }
+        target.insert_str(0, if cfg!(windows) { "file:///" } else { "file://" });
+        if path_is_relative {
+            target.insert_str(if cfg!(windows) { 8 } else { 7 }, &cwd_normalized);
+            target.insert_str(
+                if cfg!(windows) { 8 } else { 7 } + &cwd_normalized.len(),
+                "/",
+            );
+        }
+        target_url = target.as_str();
+    } else {
+        target.insert_str(0, "http://");
+        target_url = target.as_str();
+    }
+
+    let mut output = Output::new(&app_args.output).expect("Could not prepare output");
+
+    // Initialize client
+    let mut cache = HashMap::new();
+    let mut header_map = HeaderMap::new();
+    header_map.insert(
+        USER_AGENT,
+        HeaderValue::from_str(&app_args.user_agent).expect("Invalid User-Agent header specified"),
+    );
+
+    let timeout: u64 = if app_args.timeout > 0 {
+        app_args.timeout
+    } else {
+        std::u64::MAX / 4
+    };
+    let client = Client::builder()
+        .timeout(Duration::from_secs(timeout))
+        .danger_accept_invalid_certs(app_args.insecure)
+        .default_headers(header_map)
+        .build()
+        .expect("Failed to initialize HTTP client");
+
+    // Retrieve root document
+    if is_file_url(target_url) || is_http_url(target_url) {
+        let (data, final_url) = retrieve_asset(
+            &mut cache,
+            &client,
+            target_url,
+            target_url,
+            false,
+            "",
+            app_args.silent,
+        )
+        .expect("Could not retrieve target document");
+        base_url = final_url;
+        dom = html_to_dom(&data);
+    } else if is_data_url(target_url) {
+        let text: String = data_url_to_text(target_url);
+        if text.len() == 0 {
+            eprintln!("Unsupported data URL input");
+            process::exit(1);
+        }
+        base_url = str!(target_url);
+        dom = html_to_dom(&text);
+    } else {
+        process::exit(1);
+    }
+
+    walk_and_embed_assets(
+        &mut cache,
+        &client,
+        &base_url,
+        &dom.document,
+        app_args.no_css,
+        app_args.no_js,
+        app_args.no_images,
+        app_args.silent,
+        app_args.no_frames,
+    );
+
+    let html: String = stringify_document(
+        &dom.document,
+        app_args.no_css,
+        app_args.no_frames,
+        app_args.no_js,
+        app_args.no_images,
+        app_args.isolate,
+    );
+
+    output
+        .writeln_str(&html)
+        .expect("Could not write HTML output");
+}

src/tests/cli.rs

@@ -0,0 +1,501 @@
+use assert_cmd::prelude::*;
+use std::env;
+use std::io::Write;
+use std::process::Command;
+use tempfile::NamedTempFile;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_print_version() -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let out = cmd.arg("-V").output().unwrap();
+
+    // STDOUT should contain program name and version
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        format!("{} {}\n", env!("CARGO_PKG_NAME"), env!("CARGO_PKG_VERSION"))
+    );
+
+    // STDERR should be empty
+    assert_eq!(std::str::from_utf8(&out.stderr).unwrap(), "");
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}
+
+#[test]
+fn passing_bad_input_empty_target() -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let out = cmd.arg("").output().unwrap();
+
+    // STDOUT should be empty
+    assert_eq!(std::str::from_utf8(&out.stdout).unwrap(), "");
+
+    // STDERR should contain error description
+    assert_eq!(
+        std::str::from_utf8(&out.stderr).unwrap(),
+        "No target specified\n"
+    );
+
+    // The exit code should be 1
+    out.assert().code(1);
+
+    Ok(())
+}
+
+#[test]
+fn passing_bad_input_data_url() -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let out = cmd.arg("data:,Hello%2C%20World!").output().unwrap();
+
+    // STDOUT should contain HTML
+    assert_eq!(std::str::from_utf8(&out.stdout).unwrap(), "");
+
+    // STDERR should contain error description
+    assert_eq!(
+        std::str::from_utf8(&out.stderr).unwrap(),
+        "Unsupported data URL input\n"
+    );
+
+    // The exit code should be 1
+    out.assert().code(1);
+
+    Ok(())
+}
+
+#[test]
+fn passing_isolate_data_url() -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let out = cmd
+        .arg("-I")
+        .arg("data:text/html,Hello%2C%20World!")
+        .output()
+        .unwrap();
+
+    // STDOUT should contain isolated HTML
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        "<html><head>\
+<meta http-equiv=\"Content-Security-Policy\" content=\"default-src 'unsafe-inline' data:;\"></meta>\
+</head><body>Hello, World!</body></html>\n"
+    );
+
+    // STDERR should be empty
+    assert_eq!(std::str::from_utf8(&out.stderr).unwrap(), "");
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}
+
+#[test]
+fn passing_remove_css_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let out = cmd
+        .arg("-c")
+        .arg("data:text/html,<style>body{background-color:pink}</style>Hello")
+        .output()
+        .unwrap();
+
+    // STDOUT should contain HTML with no CSS
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        "<html><head>\
+<meta http-equiv=\"Content-Security-Policy\" content=\"style-src 'none';\"></meta>\
+<style></style>\
+</head><body>Hello</body></html>\n"
+    );
+
+    // STDERR should be empty
+    assert_eq!(std::str::from_utf8(&out.stderr).unwrap(), "");
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}
+
+#[test]
+fn passing_remove_frames_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let out = cmd
+        .arg("-f")
+        .arg("data:text/html,<iframe src=\"https://google.com\"></iframe>Hi")
+        .output()
+        .unwrap();
+
+    // STDOUT should contain HTML with no iframes
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        "<html><head>\
+<meta http-equiv=\"Content-Security-Policy\" content=\"frame-src 'none';child-src 'none';\"></meta>\
+</head><body><iframe src=\"\"></iframe>Hi</body></html>\n"
+    );
+
+    // STDERR should be empty
+    assert_eq!(std::str::from_utf8(&out.stderr).unwrap(), "");
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}
+
+#[test]
+fn passing_remove_images_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let out = cmd
+        .arg("-i")
+        .arg("data:text/html,<img src=\"https://google.com\"/>Hi")
+        .output()
+        .unwrap();
+
+    // STDOUT should contain HTML with no images
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        "<html>\
+<head>\
+<meta http-equiv=\"Content-Security-Policy\" content=\"img-src data:;\"></meta>\
+</head>\
+<body>\
+<img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=\">\
+Hi\
+</body>\
+</html>\n"
+    );
+
+    // STDERR should be empty
+    assert_eq!(std::str::from_utf8(&out.stderr).unwrap(), "");
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}
+
+#[test]
+fn passing_remove_js_from_data_url() -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let out = cmd
+        .arg("-j")
+        .arg("data:text/html,<script>alert(2)</script>Hi")
+        .output()
+        .unwrap();
+
+    // STDOUT should contain HTML with no JS
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        "<html>\
+<head>\
+<meta http-equiv=\"Content-Security-Policy\" content=\"script-src 'none';\"></meta>\
+<script></script></head>\
+<body>Hi</body>\
+</html>\n"
+    );
+
+    // STDERR should be empty
+    assert_eq!(std::str::from_utf8(&out.stderr).unwrap(), "");
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}
+
+#[test]
+fn passing_local_file_target_input() -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let cwd_normalized: String =
+        str!(env::current_dir().unwrap().to_str().unwrap()).replace("\\", "/");
+    let out = cmd
+        .arg(if cfg!(windows) {
+            "src\\tests\\data\\local-file.html"
+        } else {
+            "src/tests/data/local-file.html"
+        })
+        .output()
+        .unwrap();
+    let file_url_protocol: &str = if cfg!(windows) { "file:///" } else { "file://" };
+
+    // STDOUT should contain HTML from the local file
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        "<!DOCTYPE html><html lang=\"en\"><head>\n  \
+<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">\n  \
+<title>Local HTML file</title>\n  \
+<link href=\"data:text/css;base64,Ym9keSB7CiAgICBiYWNrZ3JvdW5kLWNvbG9yOiAjMDAwOwogICAgY29sb3I6ICNmZmY7Cn0K\" rel=\"stylesheet\" type=\"text/css\">\n  \
+<link href=\"data:text/css;base64,\" rel=\"stylesheet\" type=\"text/css\">\n</head>\n\n<body>\n  \
+<img alt=\"\" src=\"\">\n  \
+<a href=\"file://local-file.html/\">Tricky href</a>\n  \
+<a href=\"https://github.com/Y2Z/monolith\">Remote URL</a>\n  \
+<script src=\"data:application/javascript;base64,ZG9jdW1lbnQuYm9keS5zdHlsZS5iYWNrZ3JvdW5kQ29sb3IgPSAiZ3JlZW4iOwpkb2N1bWVudC5ib2R5LnN0eWxlLmNvbG9yID0gInJlZCI7Cg==\"></script>\n\n\n\n\
+</body></html>\n"
+    );
+
+    // STDERR should contain list of retrieved file URLs
+    assert_eq!(
+        std::str::from_utf8(&out.stderr).unwrap(),
+        format!(
+            "{file}{cwd}/src/tests/data/local-file.html\n\
+{file}{cwd}/src/tests/data/local-style.css\n\
+{file}{cwd}/src/tests/data/local-script.js\n",
+            file = file_url_protocol,
+            cwd = cwd_normalized
+        )
+    );
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}
+
+#[test]
+fn passing_local_file_target_input_absolute_target_path() -> Result<(), Box<dyn std::error::Error>>
+{
+    let cwd = env::current_dir().unwrap();
+    let cwd_normalized: String =
+        str!(env::current_dir().unwrap().to_str().unwrap()).replace("\\", "/");
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let out = cmd
+        .arg("-jciI")
+        .arg(if cfg!(windows) {
+            format!(
+                "{cwd}\\src\\tests\\data\\local-file.html",
+                cwd = cwd.to_str().unwrap()
+            )
+        } else {
+            format!(
+                "{cwd}/src/tests/data/local-file.html",
+                cwd = cwd.to_str().unwrap()
+            )
+        })
+        .output()
+        .unwrap();
+    let file_url_protocol: &str = if cfg!(windows) { "file:///" } else { "file://" };
+
+    // STDOUT should contain HTML from the local file
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        "<!DOCTYPE html><html lang=\"en\"><head>\
+<meta http-equiv=\"Content-Security-Policy\" content=\"default-src 'unsafe-inline' data:; style-src 'none'; script-src 'none'; img-src data:;\"></meta>\n  \
+<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">\n  \
+<title>Local HTML file</title>\n  \
+<link href=\"\" rel=\"stylesheet\" type=\"text/css\">\n  \
+<link href=\"\" rel=\"stylesheet\" type=\"text/css\">\n</head>\n\n<body>\n  \
+<img alt=\"\" src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=\">\n  \
+<a href=\"file://local-file.html/\">Tricky href</a>\n  \
+<a href=\"https://github.com/Y2Z/monolith\">Remote URL</a>\n  \
+<script src=\"\"></script>\n\n\n\n\
+</body></html>\n"
+    );
+
+    // STDERR should contain only the target file
+    assert_eq!(
+        std::str::from_utf8(&out.stderr).unwrap(),
+        format!(
+            "{file}{cwd}/src/tests/data/local-file.html\n",
+            file = file_url_protocol,
+            cwd = cwd_normalized,
+        )
+    );
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}
+
+#[test]
+fn passing_local_file_url_target_input() -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let cwd_normalized: String =
+        str!(env::current_dir().unwrap().to_str().unwrap()).replace("\\", "/");
+    let file_url_protocol: &str = if cfg!(windows) { "file:///" } else { "file://" };
+    let out = cmd
+        .arg("-cji")
+        .arg(if cfg!(windows) {
+            format!(
+                "{file}{cwd}/src/tests/data/local-file.html",
+                file = file_url_protocol,
+                cwd = cwd_normalized,
+            )
+        } else {
+            format!(
+                "{file}{cwd}/src/tests/data/local-file.html",
+                file = file_url_protocol,
+                cwd = cwd_normalized,
+            )
+        })
+        .output()
+        .unwrap();
+
+    // STDOUT should contain HTML from the local file
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        "<!DOCTYPE html><html lang=\"en\"><head>\
+<meta http-equiv=\"Content-Security-Policy\" content=\"style-src 'none'; script-src 'none'; img-src data:;\"></meta>\n  \
+<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">\n  \
+<title>Local HTML file</title>\n  \
+<link href=\"\" rel=\"stylesheet\" type=\"text/css\">\n  \
+<link href=\"\" rel=\"stylesheet\" type=\"text/css\">\n</head>\n\n<body>\n  \
+<img alt=\"\" src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=\">\n  \
+<a href=\"file://local-file.html/\">Tricky href</a>\n  \
+<a href=\"https://github.com/Y2Z/monolith\">Remote URL</a>\n  \
+<script src=\"\"></script>\n\n\n\n\
+</body></html>\n"
+    );
+
+    // STDERR should contain list of retrieved file URLs
+    assert_eq!(
+        std::str::from_utf8(&out.stderr).unwrap(),
+        if cfg!(windows) {
+            format!(
+                "{file}{cwd}/src/tests/data/local-file.html\n",
+                file = file_url_protocol,
+                cwd = cwd_normalized,
+            )
+        } else {
+            format!(
+                "{file}{cwd}/src/tests/data/local-file.html\n",
+                file = file_url_protocol,
+                cwd = cwd_normalized,
+            )
+        }
+    );
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}
+
+#[test]
+fn passing_security_disallow_local_assets_within_data_url_targets(
+) -> Result<(), Box<dyn std::error::Error>> {
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let out = cmd
+        .arg("data:text/html,%3Cscript%20src=\"src/tests/data/local-script.js\"%3E%3C/script%3E")
+        .output()
+        .unwrap();
+
+    // STDOUT should contain HTML with no JS in it
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        "<html><head><script src=\"\"></script></head><body></body></html>\n"
+    );
+
+    // STDERR should be empty
+    assert_eq!(std::str::from_utf8(&out.stderr).unwrap(), "");
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}
+
+#[test]
+fn passing_embed_file_url_local_asset_within_style_attribute(
+) -> Result<(), Box<dyn std::error::Error>> {
+    let file_url_prefix: &str = if cfg!(windows) { "file:///" } else { "file://" };
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let mut file_svg = NamedTempFile::new()?;
+    writeln!(file_svg, "<svg version=\"1.1\" baseProfile=\"full\" width=\"300\" height=\"200\" xmlns=\"http://www.w3.org/2000/svg\">\
+<rect width=\"100%\" height=\"100%\" fill=\"red\" />\
+<circle cx=\"150\" cy=\"100\" r=\"80\" fill=\"green\" />\
+<text x=\"150\" y=\"125\" font-size=\"60\" text-anchor=\"middle\" fill=\"white\">SVG</text>\
+</svg>\n")?;
+    let mut file_html = NamedTempFile::new()?;
+    writeln!(
+        file_html,
+        "<div style='background-image: url(\"{file}{path}\")'></div>\n",
+        file = file_url_prefix,
+        path = str!(file_svg.path().to_str().unwrap()).replace("\\", "/"),
+    )?;
+    let out = cmd.arg(file_html.path()).output().unwrap();
+
+    // STDOUT should contain HTML with date URL for background-image in it
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        "<html><head></head><body><div style=\"background-image: url('data:image/svg+xml;base64,PHN2ZyB2ZXJzaW9uPSIxLjEiIGJhc2VQcm9maWxlPSJmdWxsIiB3aWR0aD0iMzAwIiBoZWlnaHQ9IjIwMCIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48cmVjdCB3aWR0aD0iMTAwJSIgaGVpZ2h0PSIxMDAlIiBmaWxsPSJyZWQiIC8+PGNpcmNsZSBjeD0iMTUwIiBjeT0iMTAwIiByPSI4MCIgZmlsbD0iZ3JlZW4iIC8+PHRleHQgeD0iMTUwIiB5PSIxMjUiIGZvbnQtc2l6ZT0iNjAiIHRleHQtYW5jaG9yPSJtaWRkbGUiIGZpbGw9IndoaXRlIj5TVkc8L3RleHQ+PC9zdmc+Cgo=')\"></div>\n\n</body></html>\n"
+    );
+
+    // STDERR should list temporary files that got retrieved
+    assert_eq!(
+        std::str::from_utf8(&out.stderr).unwrap(),
+        format!(
+            "\
+{file}{html_path}\n\
+{file}{svg_path}\n\
+",
+            file = file_url_prefix,
+            html_path = str!(file_html.path().to_str().unwrap()).replace("\\", "/"),
+            svg_path = str!(file_svg.path().to_str().unwrap()).replace("\\", "/"),
+        )
+    );
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}
+
+#[test]
+fn passing_css_import_string() -> Result<(), Box<dyn std::error::Error>> {
+    let file_url_prefix: &str = if cfg!(windows) { "file:///" } else { "file://" };
+    let mut cmd = Command::cargo_bin(env!("CARGO_PKG_NAME"))?;
+    let mut file_css = NamedTempFile::new()?;
+    writeln!(file_css, "body{{background-color:#000;color:#fff}}")?;
+    let mut file_html = NamedTempFile::new()?;
+    writeln!(
+        file_html,
+        "<style>\n\
+@charset 'UTF-8';\n\
+\n\
+@import '{file}{css_path}';\n\
+\n\
+@import url({file}{css_path});\n\
+\n\
+@import url('{file}{css_path}')\n\
+</style>\n",
+        file = file_url_prefix,
+        css_path = str!(file_css.path().to_str().unwrap()).replace("\\", "/"),
+    )?;
+    let out = cmd.arg(file_html.path()).output().unwrap();
+
+    // STDOUT should contain embedded CSS url()'s
+    assert_eq!(
+        std::str::from_utf8(&out.stdout).unwrap(),
+        "<html><head><style>\n@charset 'UTF-8';\n\n@import 'data:text/css;base64,Ym9keXtiYWNrZ3JvdW5kLWNvbG9yOiMwMDA7Y29sb3I6I2ZmZn0K';\n\n@import url('data:text/css;base64,Ym9keXtiYWNrZ3JvdW5kLWNvbG9yOiMwMDA7Y29sb3I6I2ZmZn0K');\n\n@import url('data:text/css;base64,Ym9keXtiYWNrZ3JvdW5kLWNvbG9yOiMwMDA7Y29sb3I6I2ZmZn0K')\n</style>\n\n</head><body></body></html>\n"
+    );
+
+    // STDERR should list temporary files that got retrieved
+    assert_eq!(
+        std::str::from_utf8(&out.stderr).unwrap(),
+        format!(
+            "\
+{file}{html_path}\n\
+{file}{css_path}\n\
+{file}{css_path}\n\
+{file}{css_path}\n\
+",
+            file = file_url_prefix,
+            html_path = str!(file_html.path().to_str().unwrap()).replace("\\", "/"),
+            css_path = str!(file_css.path().to_str().unwrap()).replace("\\", "/"),
+        )
+    );
+
+    // The exit code should be 0
+    out.assert().code(0);
+
+    Ok(())
+}

src/tests/css/embed_css.rs

@@ -0,0 +1,200 @@
+use reqwest::blocking::Client;
+use std::collections::HashMap;
+
+use crate::css;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_empty_input() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    assert_eq!(css::embed_css(cache, &client, "", "", false, false,), "");
+}
+
+#[test]
+fn passing_style_exclude_unquoted_images() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    const STYLE: &str = "/* border: none;*/\
+background-image: url(https://somewhere.com/bg.png); \
+list-style: url(/assets/images/bullet.svg);\
+width:99.998%; \
+margin-top: -20px; \
+line-height: -1; \
+height: calc(100vh - 10pt)";
+
+    assert_eq!(
+        css::embed_css(
+            cache,
+            &client,
+            "https://doesntmatter.local/",
+            &STYLE,
+            true,
+            true,
+        ),
+        "/* border: none;*/\
+background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII='); \
+list-style: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=');\
+width:99.998%; \
+margin-top: -20px; \
+line-height: -1; \
+height: calc(100vh - 10pt)"
+    );
+}
+
+#[test]
+fn passing_style_exclude_single_quoted_images() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    const STYLE: &str = "/* border: none;*/\
+background-image: url('https://somewhere.com/bg.png'); \
+list-style: url('/assets/images/bullet.svg');\
+width:99.998%; \
+margin-top: -20px; \
+line-height: -1; \
+height: calc(100vh - 10pt)";
+
+    assert_eq!(
+        css::embed_css(
+            cache,
+            &client,
+            "",
+            &STYLE,
+            true,
+            true,
+        ),
+        "/* border: none;*/\
+background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII='); \
+list-style: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=');\
+width:99.998%; \
+margin-top: -20px; \
+line-height: -1; \
+height: calc(100vh - 10pt)"
+    );
+}
+
+#[test]
+fn passing_style_block() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    const CSS: &str = "\
+#id.class-name:not(:nth-child(3n+0)) {\n  \
+  // border: none;\n  \
+  background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=');\n\
+}\n\
+\n\
+html > body {}";
+
+    assert_eq!(
+        css::embed_css(cache, &client, "file:///", &CSS, false, true,),
+        CSS
+    );
+}
+
+#[test]
+fn passing_attribute_selectors() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    const CSS: &str = "\
+[data-value] {
+    /* Attribute exists */
+}
+
+[data-value='foo'] {
+    /* Attribute has this exact value */
+}
+
+[data-value*='foo'] {
+    /* Attribute value contains this value somewhere in it */
+}
+
+[data-value~='foo'] {
+    /* Attribute has this value in a space-separated list somewhere */
+}
+
+[data-value^='foo'] {
+    /* Attribute value starts with this */
+}
+
+[data-value|='foo'] {
+    /* Attribute value starts with this in a dash-separated list */
+}
+
+[data-value$='foo'] {
+    /* Attribute value ends with this */
+}
+";
+
+    assert_eq!(css::embed_css(cache, &client, "", &CSS, false, false,), CSS);
+}
+
+#[test]
+fn passing_import_string() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    const CSS: &str = "\
+@charset 'UTF-8';\n\
+\n\
+@import 'data:text/css,html{background-color:%23000}';\n\
+\n\
+@import url('data:text/css,html{color:%23fff}')\n\
+";
+
+    assert_eq!(
+        css::embed_css(
+            cache,
+            &client,
+            "https://doesntmatter.local/",
+            &CSS,
+            false,
+            true,
+        ),
+        "\
+@charset 'UTF-8';\n\
+\n\
+@import 'data:text/css;base64,ZGF0YTp0ZXh0L2NzcyxodG1se2JhY2tncm91bmQtY29sb3I6IzAwMH0=';\n\
+\n\
+@import url('data:text/css;base64,ZGF0YTp0ZXh0L2NzcyxodG1se2NvbG9yOiNmZmZ9')\n\
+"
+    );
+}
+
+#[test]
+fn passing_hash_urls() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    const CSS: &str = "\
+body {\n    \
+    behavior: url(#default#something);\n\
+}\n\
+\n\
+.scissorHalf {\n    \
+    offset-path: url(#somePath);\n\
+}\n\
+";
+
+    assert_eq!(
+        css::embed_css(
+            cache,
+            &client,
+            "https://doesntmatter.local/",
+            &CSS,
+            false,
+            true,
+        ),
+        CSS
+    );
+}

src/tests/css/enquote.rs

@@ -0,0 +1,50 @@
+use crate::css;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_empty_input_single_quotes() {
+    assert_eq!(css::enquote(str!(""), false), "''");
+}
+
+#[test]
+fn passing_empty_input_double_quotes() {
+    assert_eq!(css::enquote(str!(""), true), "\"\"");
+}
+
+#[test]
+fn passing_apostrophes_single_quotes() {
+    assert_eq!(
+        css::enquote(str!("It's a lovely day, don't you think?"), false),
+        "'It\\'s a lovely day, don\\'t you think?'"
+    );
+}
+
+#[test]
+fn passing_apostrophes_double_quotes() {
+    assert_eq!(
+        css::enquote(str!("It's a lovely day, don't you think?"), true),
+        "\"It's a lovely day, don't you think?\""
+    );
+}
+
+#[test]
+fn passing_feet_and_inches_single_quotes() {
+    assert_eq!(
+        css::enquote(str!("5'2\", 6'5\""), false),
+        "'5\\'2\", 6\\'5\"'"
+    );
+}
+
+#[test]
+fn passing_feet_and_inches_double_quotes() {
+    assert_eq!(
+        css::enquote(str!("5'2\", 6'5\""), true),
+        "\"5'2\\\", 6'5\\\"\""
+    );
+}

src/tests/css/is_image_url_prop.rs

@@ -0,0 +1,88 @@
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[cfg(test)]
+mod passing {
+    use crate::css;
+
+    #[test]
+    fn backrgound() {
+        assert!(css::is_image_url_prop("background"));
+    }
+
+    #[test]
+    fn backrgound_image() {
+        assert!(css::is_image_url_prop("background-image"));
+    }
+
+    #[test]
+    fn backrgound_image_uppercase() {
+        assert!(css::is_image_url_prop("BACKGROUND-IMAGE"));
+    }
+
+    #[test]
+    fn border_image() {
+        assert!(css::is_image_url_prop("border-image"));
+    }
+
+    #[test]
+    fn content() {
+        assert!(css::is_image_url_prop("content"));
+    }
+
+    #[test]
+    fn cursor() {
+        assert!(css::is_image_url_prop("cursor"));
+    }
+
+    #[test]
+    fn list_style() {
+        assert!(css::is_image_url_prop("list-style"));
+    }
+
+    #[test]
+    fn list_style_image() {
+        assert!(css::is_image_url_prop("list-style-image"));
+    }
+
+    #[test]
+    fn mask_image() {
+        assert!(css::is_image_url_prop("mask-image"));
+    }
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[cfg(test)]
+mod failing {
+    use crate::css;
+
+    #[test]
+    fn empty() {
+        assert!(!css::is_image_url_prop(""));
+    }
+
+    #[test]
+    fn width() {
+        assert!(!css::is_image_url_prop("width"));
+    }
+
+    #[test]
+    fn color() {
+        assert!(!css::is_image_url_prop("color"));
+    }
+
+    #[test]
+    fn z_index() {
+        assert!(!css::is_image_url_prop("z-index"));
+    }
+}

src/tests/css/mod.rs

@@ -0,0 +1,3 @@
+mod embed_css;
+mod enquote;
+mod is_image_url_prop;

src/tests/data/local-file.html

@@ -0,0 +1,19 @@
+<!doctype html>
+
+<html lang="en">
+
+<head>
+  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+  <title>Local HTML file</title>
+  <link href="local-style.css" rel="stylesheet" type="text/css" />
+  <link href="local-style-does-not-exist.css" rel="stylesheet" type="text/css" />
+</head>
+
+<body>
+  <img src="monolith.png" alt="" />
+  <a href="//local-file.html">Tricky href</a>
+  <a href="https://github.com/Y2Z/monolith">Remote URL</a>
+  <script src="local-script.js"></script>
+</body>
+
+</html>

src/tests/data/local-script.js

@@ -0,0 +1,2 @@
+document.body.style.backgroundColor = "green";
+document.body.style.color = "red";

src/tests/data/local-style.css

@@ -0,0 +1,4 @@
+body {
+    background-color: #000;
+    color: #fff;
+}

src/tests/html/get_node_name.rs

@@ -0,0 +1,49 @@
+use crate::html;
+use html5ever::rcdom::{Handle, NodeData};
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn get_node_name() {
+    let html = "<!doctype html><html><HEAD></HEAD><body><div><P></P></div></body></html>";
+    let dom = html::html_to_dom(&html);
+    let mut count = 0;
+
+    fn test_walk(node: &Handle, i: &mut i8) {
+        *i += 1;
+
+        match &node.data {
+            NodeData::Document => {
+                for child in node.children.borrow().iter() {
+                    test_walk(child, &mut *i);
+                }
+            }
+            NodeData::Element { ref name, .. } => {
+                let node_name = name.local.as_ref().to_string();
+                let parent = html::get_parent_node(node);
+                let parent_node_name = html::get_node_name(&parent);
+                if node_name == "head" || node_name == "body" {
+                    assert_eq!(parent_node_name, "html");
+                } else if node_name == "div" {
+                    assert_eq!(parent_node_name, "body");
+                } else if node_name == "p" {
+                    assert_eq!(parent_node_name, "div");
+                }
+
+                for child in node.children.borrow().iter() {
+                    test_walk(child, &mut *i);
+                }
+            }
+            _ => (),
+        };
+    }
+
+    test_walk(&dom.document, &mut count);
+
+    assert_eq!(count, 7);
+}

src/tests/html/is_icon.rs

@@ -0,0 +1,50 @@
+use crate::html;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_icon() {
+    assert!(html::is_icon("icon"));
+}
+
+#[test]
+fn passing_shortcut_icon_capitalized() {
+    assert!(html::is_icon("Shortcut Icon"));
+}
+
+#[test]
+fn passing_icon_uppercase() {
+    assert!(html::is_icon("ICON"));
+}
+
+#[test]
+fn passing_mask_icon() {
+    assert!(html::is_icon("mask-icon"));
+}
+
+#[test]
+fn passing_fluid_icon() {
+    assert!(html::is_icon("fluid-icon"));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_stylesheet() {
+    assert!(!html::is_icon("stylesheet"));
+}
+
+#[test]
+fn failing_empty_string() {
+    assert!(!html::is_icon(""));
+}

src/tests/html/mod.rs

@@ -0,0 +1,4 @@
+mod get_node_name;
+mod is_icon;
+mod stringify_document;
+mod walk_and_embed_assets;

src/tests/html/stringify_document.rs

@@ -0,0 +1,188 @@
+use crate::html;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_div_as_root_element() {
+    let html = "<div><script src=\"some.js\"></script></div>";
+    let dom = html::html_to_dom(&html);
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_isolate: bool = false;
+
+    assert_eq!(
+        html::stringify_document(
+            &dom.document,
+            opt_no_css,
+            opt_no_frames,
+            opt_no_js,
+            opt_no_images,
+            opt_isolate,
+        ),
+        "<html><head></head><body><div><script src=\"some.js\"></script></div></body></html>"
+    );
+}
+
+#[test]
+fn passing_full_page_with_no_html_head_or_body() {
+    let html = "<title>Isolated document</title>\
+                <link rel=\"something\" href=\"some.css\" />\
+                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
+                <div><script src=\"some.js\"></script></div>";
+    let dom = html::html_to_dom(&html);
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_isolate: bool = true;
+
+    assert_eq!(
+        html::stringify_document(
+            &dom.document,
+            opt_no_css,
+            opt_no_frames,
+            opt_no_js,
+            opt_no_images,
+            opt_isolate,
+        ),
+        "<html>\
+            <head>\
+                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src 'unsafe-inline' data:;\"></meta>\
+                <title>Isolated document</title>\
+                <link rel=\"something\" href=\"some.css\">\
+                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
+            </head>\
+            <body>\
+                <div>\
+                    <script src=\"some.js\"></script>\
+                </div>\
+            </body>\
+         </html>"
+    );
+}
+
+#[test]
+fn passing_doctype_and_the_rest_no_html_head_or_body() {
+    let html = "<!doctype html>\
+                <title>Unstyled document</title>\
+                <link rel=\"stylesheet\" href=\"main.css\"/>\
+                <div style=\"display: none;\"></div>";
+    let dom = html::html_to_dom(&html);
+
+    let opt_no_css: bool = true;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_isolate: bool = false;
+
+    assert_eq!(
+        html::stringify_document(
+            &dom.document,
+            opt_no_css,
+            opt_no_frames,
+            opt_no_js,
+            opt_no_images,
+            opt_isolate,
+        ),
+        "<!DOCTYPE html>\
+         <html>\
+         <head>\
+         <meta http-equiv=\"Content-Security-Policy\" content=\"style-src 'none';\"></meta>\
+         <title>Unstyled document</title>\
+         <link rel=\"stylesheet\" href=\"main.css\">\
+         </head>\
+         <body><div style=\"display: none;\"></div></body>\
+         </html>"
+    );
+}
+
+#[test]
+fn passing_doctype_and_the_rest_no_html_head_or_body_forbid_frames() {
+    let html = "<!doctype html>\
+                <title>Frameless document</title>\
+                <link rel=\"something\"/>\
+                <div><script src=\"some.js\"></script></div>";
+    let dom = html::html_to_dom(&html);
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = true;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_isolate: bool = false;
+
+    assert_eq!(
+        html::stringify_document(
+            &dom.document,
+            opt_no_css,
+            opt_no_frames,
+            opt_no_js,
+            opt_no_images,
+            opt_isolate,
+        ),
+        "<!DOCTYPE html>\
+            <html>\
+            <head>\
+            <meta http-equiv=\"Content-Security-Policy\" content=\"frame-src 'none';child-src 'none';\"></meta>\
+            <title>Frameless document</title>\
+            <link rel=\"something\">\
+            </head>\
+            <body><div><script src=\"some.js\"></script></div></body>\
+            </html>"
+    );
+}
+
+#[test]
+fn passing_doctype_and_the_rest_all_forbidden() {
+    let html = "<!doctype html>\
+                <title>no-frame no-css no-js no-image isolated document</title>\
+                <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
+                <link rel=\"stylesheet\" href=\"some.css\">\
+                <div>\
+                <script src=\"some.js\"></script>\
+                <img style=\"width: 100%;\" src=\"some.png\" />\
+                <iframe src=\"some.html\"></iframe>\
+                </div>";
+    let dom = html::html_to_dom(&html);
+
+    let opt_isolate: bool = true;
+    let opt_no_css: bool = true;
+    let opt_no_frames: bool = true;
+    let opt_no_js: bool = true;
+    let opt_no_images: bool = true;
+
+    assert_eq!(
+        html::stringify_document(
+            &dom.document,
+            opt_no_css,
+            opt_no_frames,
+            opt_no_js,
+            opt_no_images,
+            opt_isolate,
+        ),
+        "<!DOCTYPE html>\
+            <html>\
+                <head>\
+                    <meta http-equiv=\"Content-Security-Policy\" content=\"default-src 'unsafe-inline' data:; style-src 'none'; frame-src 'none';child-src 'none'; script-src 'none'; img-src data:;\"></meta>\
+                    <title>no-frame no-css no-js no-image isolated document</title>\
+                    <meta http-equiv=\"Content-Security-Policy\" content=\"default-src https:\">\
+                    <link rel=\"stylesheet\" href=\"some.css\">\
+                </head>\
+                <body>\
+                    <div>\
+                        <script src=\"some.js\"></script>\
+                        <img style=\"width: 100%;\" src=\"some.png\">\
+                        <iframe src=\"some.html\"></iframe>\
+                    </div>\
+                </body>\
+            </html>"
+    );
+}

src/tests/html/walk_and_embed_assets.rs

@@ -0,0 +1,398 @@
+use crate::html;
+use html5ever::serialize::{serialize, SerializeOpts};
+use reqwest::blocking::Client;
+use std::collections::HashMap;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_basic() {
+    let cache = &mut HashMap::new();
+
+    let html = "<div><P></P></div>";
+    let dom = html::html_to_dom(&html);
+    let url = "http://localhost";
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_silent = true;
+
+    let client = Client::new();
+
+    html::walk_and_embed_assets(
+        cache,
+        &client,
+        &url,
+        &dom.document,
+        opt_no_css,
+        opt_no_js,
+        opt_no_images,
+        opt_silent,
+        opt_no_frames,
+    );
+
+    let mut buf: Vec<u8> = Vec::new();
+    serialize(&mut buf, &dom.document, SerializeOpts::default()).unwrap();
+
+    assert_eq!(
+        buf.iter().map(|&c| c as char).collect::<String>(),
+        "<html><head></head><body><div><p></p></div></body></html>"
+    );
+}
+
+#[test]
+fn passing_ensure_no_recursive_iframe() {
+    let html = "<div><P></P><iframe src=\"\"></iframe></div>";
+    let dom = html::html_to_dom(&html);
+    let url = "http://localhost";
+    let cache = &mut HashMap::new();
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_silent = true;
+
+    let client = Client::new();
+
+    html::walk_and_embed_assets(
+        cache,
+        &client,
+        &url,
+        &dom.document,
+        opt_no_css,
+        opt_no_js,
+        opt_no_images,
+        opt_silent,
+        opt_no_frames,
+    );
+
+    let mut buf: Vec<u8> = Vec::new();
+    serialize(&mut buf, &dom.document, SerializeOpts::default()).unwrap();
+
+    assert_eq!(
+        buf.iter().map(|&c| c as char).collect::<String>(),
+        "<html><head></head><body><div><p></p><iframe src=\"\"></iframe></div></body></html>"
+    );
+}
+
+#[test]
+fn passing_ensure_no_recursive_frame() {
+    let html = "<frameset><frame src=\"\"></frameset>";
+    let dom = html::html_to_dom(&html);
+    let url = "http://localhost";
+    let cache = &mut HashMap::new();
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_silent = true;
+
+    let client = Client::new();
+
+    html::walk_and_embed_assets(
+        cache,
+        &client,
+        &url,
+        &dom.document,
+        opt_no_css,
+        opt_no_js,
+        opt_no_images,
+        opt_silent,
+        opt_no_frames,
+    );
+
+    let mut buf: Vec<u8> = Vec::new();
+    serialize(&mut buf, &dom.document, SerializeOpts::default()).unwrap();
+
+    assert_eq!(
+        buf.iter().map(|&c| c as char).collect::<String>(),
+        "<html><head></head><frameset><frame src=\"\"></frameset></html>"
+    );
+}
+
+#[test]
+fn passing_no_css() {
+    let html = "<link rel=\"stylesheet\" href=\"main.css\">\
+                <style>html{background-color: #000;}</style>\
+                <div style=\"display: none;\"></div>";
+    let dom = html::html_to_dom(&html);
+    let url = "http://localhost";
+    let cache = &mut HashMap::new();
+
+    let opt_no_css: bool = true;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_silent = true;
+    let client = Client::new();
+
+    html::walk_and_embed_assets(
+        cache,
+        &client,
+        &url,
+        &dom.document,
+        opt_no_css,
+        opt_no_js,
+        opt_no_images,
+        opt_silent,
+        opt_no_frames,
+    );
+
+    let mut buf: Vec<u8> = Vec::new();
+    serialize(&mut buf, &dom.document, SerializeOpts::default()).unwrap();
+
+    assert_eq!(
+        buf.iter().map(|&c| c as char).collect::<String>(),
+        "<html>\
+         <head>\
+         <link rel=\"stylesheet\" href=\"\">\
+         <style></style>\
+         </head>\
+         <body>\
+         <div></div>\
+         </body>\
+         </html>"
+    );
+}
+
+#[test]
+fn passing_no_images() {
+    let html = "<link rel=\"icon\" href=\"favicon.ico\">\
+                <div><img src=\"http://localhost/assets/mono_lisa.png\" /></div>";
+    let dom = html::html_to_dom(&html);
+    let url = "http://localhost";
+    let cache = &mut HashMap::new();
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = true;
+    let opt_silent = true;
+
+    let client = Client::new();
+
+    html::walk_and_embed_assets(
+        cache,
+        &client,
+        &url,
+        &dom.document,
+        opt_no_css,
+        opt_no_js,
+        opt_no_images,
+        opt_silent,
+        opt_no_frames,
+    );
+
+    let mut buf: Vec<u8> = Vec::new();
+    serialize(&mut buf, &dom.document, SerializeOpts::default()).unwrap();
+
+    assert_eq!(
+        buf.iter().map(|&c| c as char).collect::<String>(),
+        "<html>\
+         <head>\
+         <link rel=\"icon\" href=\"\">\
+         </head>\
+         <body>\
+         <div>\
+         <img src=\"data:image/png;base64,\
+         iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0\
+         lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=\">\
+         </div>\
+         </body>\
+         </html>"
+    );
+}
+
+#[test]
+fn passing_no_body_background_images() {
+    let html = "<body background=\"no/such/image.png\" background=\"no/such/image2.png\"></body>";
+    let dom = html::html_to_dom(&html);
+    let url = "http://localhost";
+    let cache = &mut HashMap::new();
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = true;
+    let opt_silent = true;
+
+    let client = Client::new();
+
+    html::walk_and_embed_assets(
+        cache,
+        &client,
+        &url,
+        &dom.document,
+        opt_no_css,
+        opt_no_js,
+        opt_no_images,
+        opt_silent,
+        opt_no_frames,
+    );
+
+    let mut buf: Vec<u8> = Vec::new();
+    serialize(&mut buf, &dom.document, SerializeOpts::default()).unwrap();
+
+    assert_eq!(
+        buf.iter().map(|&c| c as char).collect::<String>(),
+        "<html><head></head><body></body></html>"
+    );
+}
+
+#[test]
+fn passing_no_frames() {
+    let html = "<frameset><frame src=\"http://trackbook.com\"></frameset>";
+    let dom = html::html_to_dom(&html);
+    let url = "http://localhost";
+    let cache = &mut HashMap::new();
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = true;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_silent = true;
+    let client = Client::new();
+
+    html::walk_and_embed_assets(
+        cache,
+        &client,
+        &url,
+        &dom.document,
+        opt_no_css,
+        opt_no_js,
+        opt_no_images,
+        opt_silent,
+        opt_no_frames,
+    );
+
+    let mut buf: Vec<u8> = Vec::new();
+    serialize(&mut buf, &dom.document, SerializeOpts::default()).unwrap();
+
+    assert_eq!(
+        buf.iter().map(|&c| c as char).collect::<String>(),
+        "<html><head></head><frameset><frame src=\"\"></frameset></html>"
+    );
+}
+
+#[test]
+fn passing_no_iframes() {
+    let html = "<iframe src=\"http://trackbook.com\"></iframe>";
+    let dom = html::html_to_dom(&html);
+    let url = "http://localhost";
+    let cache = &mut HashMap::new();
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = true;
+    let opt_no_js: bool = false;
+    let opt_no_images: bool = false;
+    let opt_silent = true;
+    let client = Client::new();
+
+    html::walk_and_embed_assets(
+        cache,
+        &client,
+        &url,
+        &dom.document,
+        opt_no_css,
+        opt_no_js,
+        opt_no_images,
+        opt_silent,
+        opt_no_frames,
+    );
+
+    let mut buf: Vec<u8> = Vec::new();
+    serialize(&mut buf, &dom.document, SerializeOpts::default()).unwrap();
+
+    assert_eq!(
+        buf.iter().map(|&c| c as char).collect::<String>(),
+        "<html><head></head><body><iframe src=\"\"></iframe></body></html>"
+    );
+}
+
+#[test]
+fn passing_no_js() {
+    let html = "<div onClick=\"void(0)\">\
+                <script src=\"http://localhost/assets/some.js\"></script>\
+                <script>alert(1)</script>\
+                </div>";
+    let dom = html::html_to_dom(&html);
+    let url = "http://localhost";
+    let cache = &mut HashMap::new();
+
+    let opt_no_css: bool = false;
+    let opt_no_frames: bool = false;
+    let opt_no_js: bool = true;
+    let opt_no_images: bool = false;
+    let opt_silent = true;
+
+    let client = Client::new();
+
+    html::walk_and_embed_assets(
+        cache,
+        &client,
+        &url,
+        &dom.document,
+        opt_no_css,
+        opt_no_js,
+        opt_no_images,
+        opt_silent,
+        opt_no_frames,
+    );
+
+    let mut buf: Vec<u8> = Vec::new();
+    serialize(&mut buf, &dom.document, SerializeOpts::default()).unwrap();
+
+    assert_eq!(
+        buf.iter().map(|&c| c as char).collect::<String>(),
+        "<html><head></head><body><div><script src=\"\"></script>\
+         <script></script></div></body></html>"
+    );
+}
+
+#[test]
+fn passing_with_no_integrity() {
+    let html = "<title>No integrity</title>\
+                <link integrity=\"sha384-...\" rel=\"something\"/>\
+                <script integrity=\"sha384-...\" src=\"some.js\"></script>";
+    let dom = html::html_to_dom(&html);
+    let url = "http://localhost";
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+    let opt_no_css: bool = true;
+    let opt_no_frames: bool = true;
+    let opt_no_js: bool = true;
+    let opt_no_images: bool = true;
+    let opt_silent = true;
+
+    html::walk_and_embed_assets(
+        cache,
+        &client,
+        &url,
+        &dom.document,
+        opt_no_css,
+        opt_no_js,
+        opt_no_images,
+        opt_silent,
+        opt_no_frames,
+    );
+
+    let mut buf: Vec<u8> = Vec::new();
+    serialize(&mut buf, &dom.document, SerializeOpts::default()).unwrap();
+
+    assert_eq!(
+        buf.iter().map(|&c| c as char).collect::<String>(),
+        "<html>\
+         <head><title>No integrity</title><link rel=\"something\"><script src=\"\"></script></head>\
+         <body></body>\
+         </html>"
+    );
+}

src/tests/js/attr_is_event_handler.rs

@@ -0,0 +1,45 @@
+use crate::js;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_onblur_camelcase() {
+    assert!(js::attr_is_event_handler("onBlur"));
+}
+
+#[test]
+fn passing_onclick_lowercase() {
+    assert!(js::attr_is_event_handler("onclick"));
+}
+
+#[test]
+fn passing_onclick_camelcase() {
+    assert!(js::attr_is_event_handler("onClick"));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_href() {
+    assert!(!js::attr_is_event_handler("href"));
+}
+
+#[test]
+fn failing_empty_string() {
+    assert!(!js::attr_is_event_handler(""));
+}
+
+#[test]
+fn failing_class() {
+    assert!(!js::attr_is_event_handler("class"));
+}

src/tests/js/mod.rs

@@ -0,0 +1 @@
+mod attr_is_event_handler;

src/tests/mod.rs

@@ -0,0 +1,5 @@
+mod cli;
+mod css;
+mod html;
+mod js;
+mod utils;

src/tests/utils/clean_url.rs

@@ -0,0 +1,32 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_removes_fragment() {
+    assert_eq!(
+        utils::clean_url("https://somewhere.com/font.eot#iefix"),
+        "https://somewhere.com/font.eot"
+    );
+}
+
+#[test]
+fn passing_removes_empty_fragment() {
+    assert_eq!(
+        utils::clean_url("https://somewhere.com/font.eot#"),
+        "https://somewhere.com/font.eot"
+    );
+}
+
+#[test]
+fn passing_removes_empty_query_and_empty_fragment() {
+    assert_eq!(
+        utils::clean_url("https://somewhere.com/font.eot?#"),
+        "https://somewhere.com/font.eot"
+    );
+}

src/tests/utils/data_to_data_url.rs

@@ -0,0 +1,28 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_encode_string_with_specific_media_type() {
+    let mime = "application/javascript";
+    let data = "var word = 'hello';\nalert(word);\n";
+    let data_url = utils::data_to_data_url(mime, data.as_bytes(), "", "");
+
+    assert_eq!(
+        &data_url,
+        "data:application/javascript;base64,dmFyIHdvcmQgPSAnaGVsbG8nOwphbGVydCh3b3JkKTsK"
+    );
+}
+
+#[test]
+fn passing_encode_append_fragment() {
+    let data = "<svg></svg>\n";
+    let data_url = utils::data_to_data_url("text/css", data.as_bytes(), "", "fragment");
+
+    assert_eq!(&data_url, "data:text/css;base64,PHN2Zz48L3N2Zz4K#fragment");
+}

src/tests/utils/data_url_to_text.rs

@@ -0,0 +1,58 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_parse_text_html_base64() {
+    assert_eq!(
+        utils::data_url_to_text("data:text/html;base64,V29yayBleHBhbmRzIHNvIGFzIHRvIGZpbGwgdGhlIHRpbWUgYXZhaWxhYmxlIGZvciBpdHMgY29tcGxldGlvbg=="),
+        "Work expands so as to fill the time available for its completion"
+    );
+}
+
+#[test]
+fn passing_parse_text_html_utf8() {
+    assert_eq!(
+        utils::data_url_to_text(
+            "data:text/html;utf8,Work expands so as to fill the time available for its completion"
+        ),
+        "Work expands so as to fill the time available for its completion"
+    );
+}
+
+#[test]
+fn passing_parse_text_html_plaintext() {
+    assert_eq!(
+        utils::data_url_to_text(
+            "data:text/html,Work expands so as to fill the time available for its completion"
+        ),
+        "Work expands so as to fill the time available for its completion"
+    );
+}
+
+#[test]
+fn passing_parse_text_html_charset_utf_8_between_two_whitespaces() {
+    assert_eq!(
+        utils::data_url_to_text(
+            " data:text/html;charset=utf-8,Work expands so as to fill the time available for its completion "
+        ),
+        "Work expands so as to fill the time available for its completion"
+    );
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_just_word_data() {
+    assert_eq!(utils::data_url_to_text("data"), "");
+}

src/tests/utils/decode_url.rs

@@ -0,0 +1,26 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_decode_unicode_characters() {
+    assert_eq!(
+        utils::decode_url(str!(
+            "%E6%A4%9C%E3%83%92%E3%83%A0%E8%A7%A3%E5%A1%97%E3%82%83%E3%83%83%20%3D%20%E3%82%B5"
+        )),
+        "検ヒム解塗ゃッ = サ"
+    );
+}
+
+#[test]
+fn passing_decode_file_url() {
+    assert_eq!(
+        utils::decode_url(str!("file:///tmp/space%20here/test%231.html")),
+        "file:///tmp/space here/test#1.html"
+    );
+}

src/tests/utils/detect_media_type.rs

@@ -0,0 +1,147 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_image_gif87() {
+    assert_eq!(utils::detect_media_type(b"GIF87a", ""), "image/gif");
+}
+
+#[test]
+fn passing_image_gif89() {
+    assert_eq!(utils::detect_media_type(b"GIF89a", ""), "image/gif");
+}
+
+#[test]
+fn passing_image_jpeg() {
+    assert_eq!(utils::detect_media_type(b"\xFF\xD8\xFF", ""), "image/jpeg");
+}
+
+#[test]
+fn passing_image_png() {
+    assert_eq!(
+        utils::detect_media_type(b"\x89PNG\x0D\x0A\x1A\x0A", ""),
+        "image/png"
+    );
+}
+
+#[test]
+fn passing_image_svg() {
+    assert_eq!(utils::detect_media_type(b"<svg ", ""), "image/svg+xml");
+}
+
+#[test]
+fn passing_image_webp() {
+    assert_eq!(
+        utils::detect_media_type(b"RIFF....WEBPVP8 ", ""),
+        "image/webp"
+    );
+}
+
+#[test]
+fn passing_image_icon() {
+    assert_eq!(
+        utils::detect_media_type(b"\x00\x00\x01\x00", ""),
+        "image/x-icon"
+    );
+}
+
+#[test]
+fn passing_image_svg_filename() {
+    assert_eq!(
+        utils::detect_media_type(b"<?xml ", "local-file.svg"),
+        "image/svg+xml"
+    );
+}
+
+#[test]
+fn passing_image_svg_url_uppercase() {
+    assert_eq!(
+        utils::detect_media_type(b"", "https://some-site.com/images/local-file.SVG"),
+        "image/svg+xml"
+    );
+}
+
+#[test]
+fn passing_audio_mpeg() {
+    assert_eq!(utils::detect_media_type(b"ID3", ""), "audio/mpeg");
+}
+
+#[test]
+fn passing_audio_mpeg_2() {
+    assert_eq!(utils::detect_media_type(b"\xFF\x0E", ""), "audio/mpeg");
+}
+
+#[test]
+fn passing_audio_mpeg_3() {
+    assert_eq!(utils::detect_media_type(b"\xFF\x0F", ""), "audio/mpeg");
+}
+
+#[test]
+fn passing_audio_ogg() {
+    assert_eq!(utils::detect_media_type(b"OggS", ""), "audio/ogg");
+}
+
+#[test]
+fn passing_audio_wav() {
+    assert_eq!(
+        utils::detect_media_type(b"RIFF....WAVEfmt ", ""),
+        "audio/wav"
+    );
+}
+
+#[test]
+fn passing_audio_flac() {
+    assert_eq!(utils::detect_media_type(b"fLaC", ""), "audio/x-flac");
+}
+
+#[test]
+fn passing_video_avi() {
+    assert_eq!(
+        utils::detect_media_type(b"RIFF....AVI LIST", ""),
+        "video/avi"
+    );
+}
+
+#[test]
+fn passing_video_mp4() {
+    assert_eq!(utils::detect_media_type(b"....ftyp", ""), "video/mp4");
+}
+
+#[test]
+fn passing_video_mpeg() {
+    assert_eq!(
+        utils::detect_media_type(b"\x00\x00\x01\x0B", ""),
+        "video/mpeg"
+    );
+}
+
+#[test]
+fn passing_video_quicktime() {
+    assert_eq!(utils::detect_media_type(b"....moov", ""), "video/quicktime");
+}
+
+#[test]
+fn passing_video_webm() {
+    assert_eq!(
+        utils::detect_media_type(b"\x1A\x45\xDF\xA3", ""),
+        "video/webm"
+    );
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_unknown_media_type() {
+    assert_eq!(utils::detect_media_type(b"abcdef0123456789", ""), "");
+}

src/tests/utils/file_url_to_fs_path.rs

@@ -0,0 +1,23 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_remove_protocl_and_fragment() {
+    if cfg!(windows) {
+        assert_eq!(
+            utils::file_url_to_fs_path("file:///C:/documents/some-path/some-file.svg#fragment"),
+            "C:\\documents\\some-path\\some-file.svg"
+        );
+    } else {
+        assert_eq!(
+            utils::file_url_to_fs_path("file:///tmp/some-path/some-file.svg#fragment"),
+            "/tmp/some-path/some-file.svg"
+        );
+    }
+}

src/tests/utils/get_url_fragment.rs

@@ -0,0 +1,23 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_data_url() {
+    assert_eq!(
+        utils::get_url_fragment(
+            "data:image/svg+xml;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h#test"
+        ),
+        "test"
+    );
+}
+
+#[test]
+fn passing_https_empty() {
+    assert_eq!(utils::get_url_fragment("https://kernel.org#"), "");
+}

src/tests/utils/is_data_url.rs

@@ -0,0 +1,44 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_data_url_text_html() {
+    assert!(utils::is_data_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
+    ));
+}
+
+#[test]
+fn passing_data_url_no_media_type() {
+    assert!(utils::is_data_url(
+        "data:;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
+    ));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_https_url() {
+    assert!(!utils::is_data_url("https://kernel.org"));
+}
+
+#[test]
+fn failing_no_protocol_url() {
+    assert!(!utils::is_data_url("//kernel.org"));
+}
+
+#[test]
+fn failing_empty_string() {
+    assert!(!utils::is_data_url(""));
+}

src/tests/utils/is_file_url.rs

@@ -0,0 +1,75 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_unix_file_url() {
+    assert!(utils::is_file_url(
+        "file:///home/user/Websites/my-website/index.html"
+    ));
+}
+
+#[test]
+fn passing_windows_file_url() {
+    assert!(utils::is_file_url(
+        "file:///C:/Documents%20and%20Settings/user/Websites/my-website/assets/images/logo.png"
+    ));
+}
+
+#[test]
+fn passing_unix_url_with_backslashes() {
+    assert!(utils::is_file_url(
+        "file:\\\\\\home\\user\\Websites\\my-website\\index.html"
+    ));
+}
+
+#[test]
+fn passing_windows_file_url_with_backslashes() {
+    assert!(utils::is_file_url(
+        "file:\\\\\\C:\\Documents%20and%20Settings\\user\\Websites\\my-website\\assets\\images\\logo.png"
+    ));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_url_with_no_protocl() {
+    assert!(!utils::is_file_url("//kernel.org"));
+}
+
+#[test]
+fn failing_dot_slash_filename() {
+    assert!(!utils::is_file_url("./index.html"));
+}
+
+#[test]
+fn failing_just_filename() {
+    assert!(!utils::is_file_url("some-local-page.htm"));
+}
+
+#[test]
+fn failing_https_ip_port_url() {
+    assert!(!utils::is_file_url("https://1.2.3.4:80/www/index.html"));
+}
+
+#[test]
+fn failing_data_url() {
+    assert!(!utils::is_file_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
+    ));
+}
+
+#[test]
+fn failing_just_word_file() {
+    assert!(!utils::is_file_url("file"));
+}

src/tests/utils/is_http_url.rs

@@ -0,0 +1,57 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_http_url() {
+    assert!(utils::is_http_url("http://kernel.org"));
+}
+
+#[test]
+fn passing_https_url() {
+    assert!(utils::is_http_url("https://www.rust-lang.org/"));
+}
+
+#[test]
+fn passing_http_url_with_backslashes() {
+    assert!(utils::is_http_url("http:\\\\freebsd.org\\"));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_url_with_no_protocol() {
+    assert!(!utils::is_http_url("//kernel.org"));
+}
+
+#[test]
+fn failing_dot_slash_filename() {
+    assert!(!utils::is_http_url("./index.html"));
+}
+
+#[test]
+fn failing_just_filename() {
+    assert!(!utils::is_http_url("some-local-page.htm"));
+}
+
+#[test]
+fn failing_https_ip_port_url() {
+    assert!(!utils::is_http_url("ftp://1.2.3.4/www/index.html"));
+}
+
+#[test]
+fn failing_data_url() {
+    assert!(!utils::is_http_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h"
+    ));
+}

src/tests/utils/mod.rs

@@ -0,0 +1,13 @@
+mod clean_url;
+mod data_to_data_url;
+mod data_url_to_text;
+mod decode_url;
+mod detect_media_type;
+mod file_url_to_fs_path;
+mod get_url_fragment;
+mod is_data_url;
+mod is_file_url;
+mod is_http_url;
+mod resolve_url;
+mod retrieve_asset;
+mod url_has_protocol;

src/tests/utils/resolve_url.rs

@@ -0,0 +1,229 @@
+use url::ParseError;
+
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_from_https_to_level_up_relative() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url("https://www.kernel.org", "../category/signatures.html")?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.kernel.org/category/signatures.html"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_just_filename_to_full_https_url() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "saved_page.htm",
+        "https://www.kernel.org/category/signatures.html",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.kernel.org/category/signatures.html"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_https_url_to_url_with_no_protocol() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "https://www.kernel.org",
+        "//www.kernel.org/theme/images/logos/tux.png",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.kernel.org/theme/images/logos/tux.png"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_https_url_to_url_with_no_protocol_and_on_different_hostname(
+) -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "https://www.kernel.org",
+        "//another-host.org/theme/images/logos/tux.png",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://another-host.org/theme/images/logos/tux.png"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_https_url_to_relative_root_path() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "https://www.kernel.org/category/signatures.html",
+        "/theme/images/logos/tux.png",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.kernel.org/theme/images/logos/tux.png"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_https_to_just_filename() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "https://www.w3schools.com/html/html_iframe.asp",
+        "default.asp",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.w3schools.com/html/default.asp"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_data_url_to_https() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h",
+        "https://www.kernel.org/category/signatures.html",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "https://www.kernel.org/category/signatures.html"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_data_url_to_data_url() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h",
+        "data:text/html;base64,PGEgaHJlZj0iaW5kZXguaHRtbCI+SG9tZTwvYT4K",
+    )?;
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "data:text/html;base64,PGEgaHJlZj0iaW5kZXguaHRtbCI+SG9tZTwvYT4K"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_file_url_to_relative_path() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "file:///home/user/Websites/my-website/index.html",
+        "assets/images/logo.png",
+    )
+    .unwrap_or(str!());
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "file:///home/user/Websites/my-website/assets/images/logo.png"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_file_url_to_relative_path_with_backslashes() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "file:\\\\\\home\\user\\Websites\\my-website\\index.html",
+        "assets\\images\\logo.png",
+    )
+    .unwrap_or(str!());
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "file:///home/user/Websites/my-website/assets/images/logo.png"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_from_data_url_to_file_url() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h",
+        "file:///etc/passwd",
+    )
+    .unwrap_or(str!());
+
+    assert_eq!(resolved_url.as_str(), "file:///etc/passwd");
+
+    Ok(())
+}
+
+#[test]
+fn passing_preserve_fragment() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "http://doesnt-matter.local/",
+        "css/fonts/fontmarvelous.svg#fontmarvelous",
+    )
+    .unwrap_or(str!());
+
+    assert_eq!(
+        resolved_url.as_str(),
+        "http://doesnt-matter.local/css/fonts/fontmarvelous.svg#fontmarvelous"
+    );
+
+    Ok(())
+}
+
+#[test]
+fn passing_resolve_from_file_url_to_file_url() -> Result<(), ParseError> {
+    let resolved_url = if cfg!(windows) {
+        utils::resolve_url("file:///c:/index.html", "file:///c:/image.png").unwrap_or(str!())
+    } else {
+        utils::resolve_url("file:///tmp/index.html", "file:///tmp/image.png").unwrap_or(str!())
+    };
+
+    assert_eq!(
+        resolved_url.as_str(),
+        if cfg!(windows) {
+            "file:///c:/image.png"
+        } else {
+            "file:///tmp/image.png"
+        }
+    );
+
+    Ok(())
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_from_data_url_to_url_with_no_protocol() -> Result<(), ParseError> {
+    let resolved_url = utils::resolve_url(
+        "data:text/html;base64,V2VsY29tZSBUbyBUaGUgUGFydHksIDxiPlBhbDwvYj4h",
+        "//www.w3schools.com/html/html_iframe.asp",
+    )
+    .unwrap_or(str!());
+
+    assert_eq!(resolved_url.as_str(), "");
+
+    Ok(())
+}

src/tests/utils/retrieve_asset.rs

@@ -0,0 +1,137 @@
+use crate::utils;
+use reqwest::blocking::Client;
+use std::collections::HashMap;
+use std::env;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_read_data_url() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    // If both source and target are data URLs,
+    // ensure the result contains target data URL
+    let (retrieved_data, final_url) = utils::retrieve_asset(
+        cache,
+        &client,
+        "data:text/html;base64,SoUrCe",
+        "data:text/html;base64,TaRgEt",
+        true,
+        "",
+        false,
+    )
+    .unwrap();
+    assert_eq!(&retrieved_data, "data:text/html;base64,TaRgEt");
+    assert_eq!(&final_url, "data:text/html;base64,TaRgEt");
+}
+
+#[test]
+fn passing_read_data_url_ignore_suggested_media_type() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    // Media type parameter should not influence data URLs
+    let (data, final_url) = utils::retrieve_asset(
+        cache,
+        &client,
+        "data:text/html;base64,SoUrCe",
+        "data:text/html;base64,TaRgEt",
+        true,
+        "image/png",
+        false,
+    )
+    .unwrap();
+    assert_eq!(&data, "data:text/html;base64,TaRgEt");
+    assert_eq!(&final_url, "data:text/html;base64,TaRgEt");
+}
+
+#[test]
+fn passing_read_local_file_with_file_url_parent() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    let file_url_protocol: &str = if cfg!(windows) { "file:///" } else { "file://" };
+
+    // Inclusion of local assets from local sources should be allowed
+    let cwd = env::current_dir().unwrap();
+    let (data, final_url) = utils::retrieve_asset(
+        cache,
+        &client,
+        &format!(
+            "{file}{cwd}/src/tests/data/local-file.html",
+            file = file_url_protocol,
+            cwd = cwd.to_str().unwrap()
+        ),
+        &format!(
+            "{file}{cwd}/src/tests/data/local-script.js",
+            file = file_url_protocol,
+            cwd = cwd.to_str().unwrap()
+        ),
+        true,
+        "application/javascript",
+        false,
+    )
+    .unwrap();
+    assert_eq!(&data, "data:application/javascript;base64,ZG9jdW1lbnQuYm9keS5zdHlsZS5iYWNrZ3JvdW5kQ29sb3IgPSAiZ3JlZW4iOwpkb2N1bWVudC5ib2R5LnN0eWxlLmNvbG9yID0gInJlZCI7Cg==");
+    assert_eq!(
+        &final_url,
+        &format!(
+            "{file}{cwd}/src/tests/data/local-script.js",
+            file = file_url_protocol,
+            cwd = cwd.to_str().unwrap()
+        )
+    );
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_read_local_file_with_data_url_parent() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    // Inclusion of local assets from data URL sources should not be allowed
+    let (data, final_url) = utils::retrieve_asset(
+        cache,
+        &client,
+        "data:text/html;base64,SoUrCe",
+        "file:///etc/passwd",
+        true,
+        "",
+        false,
+    )
+    .unwrap();
+    assert_eq!(&data, "");
+    assert_eq!(&final_url, "");
+}
+
+#[test]
+fn failing_read_local_file_with_https_parent() {
+    let cache = &mut HashMap::new();
+    let client = Client::new();
+
+    // Inclusion of local assets from remote sources should not be allowed
+    let (data, final_url) = utils::retrieve_asset(
+        cache,
+        &client,
+        "https://kernel.org/",
+        "file:///etc/passwd",
+        true,
+        "",
+        false,
+    )
+    .unwrap();
+    assert_eq!(&data, "");
+    assert_eq!(&final_url, "");
+}

src/tests/utils/url_has_protocol.rs

@@ -0,0 +1,83 @@
+use crate::utils;
+
+//  ██████╗  █████╗ ███████╗███████╗██╗███╗   ██╗ ██████╗
+//  ██╔══██╗██╔══██╗██╔════╝██╔════╝██║████╗  ██║██╔════╝
+//  ██████╔╝███████║███████╗███████╗██║██╔██╗ ██║██║  ███╗
+//  ██╔═══╝ ██╔══██║╚════██║╚════██║██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║███████║███████║██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn passing_mailto() {
+    assert!(utils::url_has_protocol(
+        "mailto:somebody@somewhere.com?subject=hello"
+    ));
+}
+
+#[test]
+fn passing_tel() {
+    assert!(utils::url_has_protocol("tel:5551234567"));
+}
+
+#[test]
+fn passing_ftp_no_slashes() {
+    assert!(utils::url_has_protocol("ftp:some-ftp-server.com"));
+}
+
+#[test]
+fn passing_ftp_with_credentials() {
+    assert!(utils::url_has_protocol(
+        "ftp://user:password@some-ftp-server.com"
+    ));
+}
+
+#[test]
+fn passing_javascript() {
+    assert!(utils::url_has_protocol("javascript:void(0)"));
+}
+
+#[test]
+fn passing_http() {
+    assert!(utils::url_has_protocol("http://news.ycombinator.com"));
+}
+
+#[test]
+fn passing_https() {
+    assert!(utils::url_has_protocol("https://github.com"));
+}
+
+#[test]
+fn passing_mailto_uppercase() {
+    assert!(utils::url_has_protocol(
+        "MAILTO:somebody@somewhere.com?subject=hello"
+    ));
+}
+
+//  ███████╗ █████╗ ██╗██╗     ██╗███╗   ██╗ ██████╗
+//  ██╔════╝██╔══██╗██║██║     ██║████╗  ██║██╔════╝
+//  █████╗  ███████║██║██║     ██║██╔██╗ ██║██║  ███╗
+//  ██╔══╝  ██╔══██║██║██║     ██║██║╚██╗██║██║   ██║
+//  ██║     ██║  ██║██║███████╗██║██║ ╚████║╚██████╔╝
+//  ╚═╝     ╚═╝  ╚═╝╚═╝╚══════╝╚═╝╚═╝  ╚═══╝ ╚═════╝
+
+#[test]
+fn failing_url_with_no_protocol() {
+    assert!(!utils::url_has_protocol(
+        "//some-hostname.com/some-file.html"
+    ));
+}
+
+#[test]
+fn failing_relative_path() {
+    assert!(!utils::url_has_protocol("some-hostname.com/some-file.html"));
+}
+
+#[test]
+fn failing_relative_to_root_path() {
+    assert!(!utils::url_has_protocol("/some-file.html"));
+}
+
+#[test]
+fn failing_empty_string() {
+    assert!(!utils::url_has_protocol(""));
+}

src/utils.rs

@@ -1,14 +1,17 @@
-extern crate base64;
+use base64;
+use reqwest::blocking::Client;
+use reqwest::header::CONTENT_TYPE;
+use std::collections::HashMap;
+use std::fs;
+use std::path::Path;
+use url::{form_urlencoded, ParseError, Url};
 
-use self::base64::encode;
-
-static MAGIC: [[&[u8]; 2]; 19]  = [
+const MAGIC: [[&[u8]; 2]; 18] = [
     // Image
     [b"GIF87a", b"image/gif"],
     [b"GIF89a", b"image/gif"],
     [b"\xFF\xD8\xFF", b"image/jpeg"],
     [b"\x89PNG\x0D\x0A\x1A\x0A", b"image/png"],
-    [b"<?xml ", b"image/svg+xml"],
     [b"<svg ", b"image/svg+xml"],
     [b"RIFF....WEBPVP8 ", b"image/webp"],
     [b"\x00\x00\x01\x00", b"image/x-icon"],
@@ -27,66 +30,275 @@ static MAGIC: [[&[u8]; 2]; 19]  = [
     [b"\x1A\x45\xDF\xA3", b"video/webm"],
 ];
 
-pub fn data_to_dataurl(mime: &str, data: &[u8]) -> String {
-    let mimetype = if mime == "" {
-        detect_mimetype(data)
+pub fn data_to_data_url(media_type: &str, data: &[u8], url: &str, fragment: &str) -> String {
+    let media_type: String = if media_type.is_empty() {
+        detect_media_type(data, &url)
     } else {
-        mime.to_string()
+        media_type.to_string()
     };
-    format!("data:{};base64,{}", mimetype, encode(data))
+    let hash: String = if fragment != "" {
+        format!("#{}", fragment)
+    } else {
+        str!()
+    };
+
+    format!(
+        "data:{};base64,{}{}",
+        media_type,
+        base64::encode(data),
+        hash
+    )
 }
 
-fn detect_mimetype(data: &[u8]) -> String {
-    let mut re = String::new();
-
-    for item in MAGIC.iter()  {
+pub fn detect_media_type(data: &[u8], url: &str) -> String {
+    for item in MAGIC.iter() {
         if data.starts_with(item[0]) {
-            re = String::from_utf8(item[1].to_vec()).unwrap();
-            break;
+            return String::from_utf8(item[1].to_vec()).unwrap();
         }
     }
 
-    re
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_data_to_dataurl() {
-        let mime = "application/javascript";
-        let data = "var word = 'hello';\nalert(word);\n";
-        let datauri = data_to_dataurl(mime, data.as_bytes());
-        assert_eq!(
-            &datauri,
-            "data:application/javascript;base64,dmFyIHdvcmQgPSAnaGVsbG8nOwphbGVydCh3b3JkKTsK"
-        );
+    if url.to_lowercase().ends_with(".svg") {
+        return str!("image/svg+xml");
     }
 
-    #[test]
-    fn test_detect_mimetype() {
-        // Image
-        assert_eq!(detect_mimetype(b"GIF87a"), "image/gif");
-        assert_eq!(detect_mimetype(b"GIF89a"), "image/gif");
-        assert_eq!(detect_mimetype(b"\xFF\xD8\xFF"), "image/jpeg");
-        assert_eq!(detect_mimetype(b"\x89PNG\x0D\x0A\x1A\x0A"), "image/png");
-        assert_eq!(detect_mimetype(b"<?xml "), "image/svg+xml");
-        assert_eq!(detect_mimetype(b"<svg "), "image/svg+xml");
-        assert_eq!(detect_mimetype(b"RIFF....WEBPVP8 "), "image/webp");
-        assert_eq!(detect_mimetype(b"\x00\x00\x01\x00"), "image/x-icon");
-        // Audio
-        assert_eq!(detect_mimetype(b"ID3"), "audio/mpeg");
-        assert_eq!(detect_mimetype(b"\xFF\x0E"), "audio/mpeg");
-        assert_eq!(detect_mimetype(b"\xFF\x0F"), "audio/mpeg");
-        assert_eq!(detect_mimetype(b"OggS"), "audio/ogg");
-        assert_eq!(detect_mimetype(b"RIFF....WAVEfmt "), "audio/wav");
-        assert_eq!(detect_mimetype(b"fLaC"), "audio/x-flac");
-        // Video
-        assert_eq!(detect_mimetype(b"RIFF....AVI LIST"), "video/avi");
-        assert_eq!(detect_mimetype(b"....ftyp"), "video/mp4");
-        assert_eq!(detect_mimetype(b"\x00\x00\x01\x0B"), "video/mpeg");
-        assert_eq!(detect_mimetype(b"....moov"), "video/quicktime");
-        assert_eq!(detect_mimetype(b"\x1A\x45\xDF\xA3"), "video/webm");
+    str!()
+}
+
+pub fn url_has_protocol<T: AsRef<str>>(url: T) -> bool {
+    Url::parse(url.as_ref())
+        .and_then(|u| Ok(u.scheme().len() > 0))
+        .unwrap_or(false)
+}
+
+pub fn is_data_url<T: AsRef<str>>(url: T) -> bool {
+    Url::parse(url.as_ref())
+        .and_then(|u| Ok(u.scheme() == "data"))
+        .unwrap_or(false)
+}
+
+pub fn is_file_url<T: AsRef<str>>(url: T) -> bool {
+    Url::parse(url.as_ref())
+        .and_then(|u| Ok(u.scheme() == "file"))
+        .unwrap_or(false)
+}
+
+pub fn is_http_url<T: AsRef<str>>(url: T) -> bool {
+    Url::parse(url.as_ref())
+        .and_then(|u| Ok(u.scheme() == "http" || u.scheme() == "https"))
+        .unwrap_or(false)
+}
+
+pub fn resolve_url<T: AsRef<str>, U: AsRef<str>>(from: T, to: U) -> Result<String, ParseError> {
+    let result = if is_http_url(to.as_ref()) {
+        to.as_ref().to_string()
+    } else {
+        Url::parse(from.as_ref())?
+            .join(to.as_ref())?
+            .as_ref()
+            .to_string()
+    };
+    Ok(result)
+}
+
+pub fn get_url_fragment<T: AsRef<str>>(url: T) -> String {
+    if Url::parse(url.as_ref()).unwrap().fragment() == None {
+        str!()
+    } else {
+        str!(Url::parse(url.as_ref()).unwrap().fragment().unwrap())
+    }
+}
+
+pub fn clean_url<T: AsRef<str>>(url: T) -> String {
+    let mut result = Url::parse(url.as_ref()).unwrap();
+
+    // Clear fragment
+    result.set_fragment(None);
+
+    // Get rid of stray question mark
+    if result.query() == Some("") {
+        result.set_query(None);
+    }
+    result.to_string()
+}
+
+pub fn data_url_to_text<T: AsRef<str>>(url: T) -> String {
+    let parsed_url = Url::parse(url.as_ref()).unwrap_or(Url::parse("http://[::1]").unwrap());
+    let path: String = parsed_url.path().to_string();
+    let comma_loc: usize = path.find(',').unwrap_or(path.len());
+
+    if comma_loc == path.len() {
+        return str!();
+    }
+
+    let meta_data: String = path.chars().take(comma_loc).collect();
+    let raw_data: String = path.chars().skip(comma_loc + 1).collect();
+
+    let data: String = decode_url(raw_data);
+
+    let meta_data_items: Vec<&str> = meta_data.split(';').collect();
+    let mut media_type: &str = "";
+    let mut encoding: &str = "";
+
+    let mut i: i8 = 0;
+    for item in &meta_data_items {
+        if i == 0 {
+            if item.eq_ignore_ascii_case("text/html") {
+                media_type = item;
+                continue;
+            }
+        }
+
+        if item.eq_ignore_ascii_case("base64") || item.eq_ignore_ascii_case("utf8") {
+            encoding = item;
+        }
+
+        i = i + 1;
+    }
+
+    if media_type.eq_ignore_ascii_case("text/html") {
+        if encoding.eq_ignore_ascii_case("base64") {
+            String::from_utf8(base64::decode(&data).unwrap_or(vec![])).unwrap_or(str!())
+        } else {
+            data
+        }
+    } else {
+        str!()
+    }
+}
+
+pub fn decode_url(input: String) -> String {
+    form_urlencoded::parse(input.as_bytes())
+        .map(|(key, val)| {
+            [
+                key.to_string(),
+                if val.to_string().len() == 0 {
+                    str!()
+                } else {
+                    str!('=')
+                },
+                val.to_string(),
+            ]
+            .concat()
+        })
+        .collect()
+}
+
+pub fn file_url_to_fs_path(url: &str) -> String {
+    if !is_file_url(url) {
+        return str!();
+    }
+
+    let cutoff_l = if cfg!(windows) { 8 } else { 7 };
+    let mut fs_file_path: String = decode_url(url.to_string()[cutoff_l..].to_string());
+    let url_fragment = get_url_fragment(url);
+    if url_fragment != "" {
+        let max_len = fs_file_path.len() - 1 - url_fragment.len();
+        fs_file_path = fs_file_path[0..max_len].to_string();
+    }
+
+    if cfg!(windows) {
+        fs_file_path = fs_file_path.replace("/", "\\");
+    }
+
+    fs_file_path
+}
+
+pub fn retrieve_asset(
+    cache: &mut HashMap<String, String>,
+    client: &Client,
+    parent_url: &str,
+    url: &str,
+    as_data_url: bool,
+    media_type: &str,
+    opt_silent: bool,
+) -> Result<(String, String), reqwest::Error> {
+    if url.len() == 0 {
+        return Ok((str!(), str!()));
+    }
+
+    let cache_key = clean_url(&url);
+
+    if is_data_url(&url) {
+        Ok((url.to_string(), url.to_string()))
+    } else if is_file_url(&url) {
+        // Check if parent_url is also file:///
+        // (if not, then we don't embed the asset)
+        if !is_file_url(&parent_url) {
+            return Ok((str!(), str!()));
+        }
+
+        let fs_file_path: String = file_url_to_fs_path(url);
+        let path = Path::new(&fs_file_path);
+        let url_fragment = get_url_fragment(url);
+        if path.exists() {
+            if !opt_silent {
+                eprintln!("{}", &url);
+            }
+
+            if as_data_url {
+                let data_url: String = data_to_data_url(
+                    &media_type,
+                    &fs::read(&fs_file_path).unwrap(),
+                    &fs_file_path,
+                    &url_fragment,
+                );
+                Ok((data_url, url.to_string()))
+            } else {
+                let data: String = fs::read_to_string(&fs_file_path).expect(url);
+                Ok((data, url.to_string()))
+            }
+        } else {
+            Ok((str!(), url.to_string()))
+        }
+    } else {
+        if cache.contains_key(&cache_key) {
+            // URL is in cache
+            if !opt_silent {
+                eprintln!("{} (from cache)", &url);
+            }
+            let data = cache.get(&cache_key).unwrap();
+            Ok((data.to_string(), url.to_string()))
+        } else {
+            // URL not in cache, we request it
+            let mut response = client.get(url).send()?;
+            let res_url = response.url().to_string();
+
+            if !opt_silent {
+                if url == res_url {
+                    eprintln!("{}", &url);
+                } else {
+                    eprintln!("{} -> {}", &url, &res_url);
+                }
+            }
+
+            let new_cache_key = clean_url(&res_url);
+
+            if as_data_url {
+                // Convert response into a byte array
+                let mut data: Vec<u8> = vec![];
+                response.copy_to(&mut data)?;
+
+                // Attempt to obtain media type by reading the Content-Type header
+                let media_type = if media_type == "" {
+                    response
+                        .headers()
+                        .get(CONTENT_TYPE)
+                        .and_then(|header| header.to_str().ok())
+                        .unwrap_or(&media_type)
+                } else {
+                    media_type
+                };
+                let url_fragment = get_url_fragment(url);
+                let data_url = data_to_data_url(&media_type, &data, url, &url_fragment);
+                // Add to cache
+                cache.insert(new_cache_key, data_url.clone());
+                Ok((data_url, res_url))
+            } else {
+                let content = response.text().unwrap();
+                // Add to cache
+                cache.insert(new_cache_key, content.clone());
+                Ok((content, res_url))
+            }
+        }
     }
 }