proof-html

proof-html is a GitHub Action to validate HTML and CSS using the Nu HTML Validator and check links, images, and more using HTMLProofer.

Usage

- uses: anishathalye/proof-html@v2
  with:
    directory: ./site

See below for a full example.

Options

Name	Description	Default
directory	The directory to scan	(required)
check_external_hash	Check whether external anchors exist	true
check_favicon	Check whether favicons are valid	true
check_html	Validate HTML	true
check_css	Validate CSS	true
check_opengraph	Check images and URLs in Open Graph metadata	true
ignore_empty_alt	Allow images with empty alt tags	false
ignore_missing_alt	Allow images with missing alt tags	false
allow_missing_href	Allow anchors with missing href tags	false
enforce_https	Require that links use HTTPS	true
swap_urls	JSON-encoded map of URL rewrite rules	(empty)
ignore_url	Newline-separated list of URLs to ignore	(empty)
ignore_url_re	Newline-separated list of URL regexes to ignore	(empty)
connect_timeout	HTTP connection timeout	30
tokens	JSON-encoded map of domains to authorization tokens	(empty)
max_concurrency	Maximum number of concurrent requests	50
timeout	HTTP request timeout	120
retries	Number of times to retry checking links	3

Most of the options correspond directly to configuration options for HTMLProofer.

tokens

tokens is a JSON-encoded map of domains to authorization tokens. So it's "doubly encoded": the workflow file is written in YAML and tokens is a string (not a map!), a JSON encoding of the data. This option can be used to provide bearer tokens to use in certain scenarios, which is useful for e.g. avoiding rate limiting. Tokens are only sent to the specified websites. Note that domains must not have a trailing slash. Here is an example of an encoding of tokens:

tokens: |
  {"https://github.com": "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
   "https://twitter.com": "yyyyyyyyyyyyyyyyyyyyyyy"}

You can also see the full example below for how to pass on the GITHUB_TOKEN supplied by the workflow runner.

swap_urls

swap_urls is a JSON-encoded map, mapping regexes to strings. This can be useful to strip a base path for an internal domain. For example:

swap_urls: |
  {"^https://example.com/": "/"}

You can also use capture groups and back-references here. For example, to ignore checking hashes for GitHub URLs (like https://github.com/anishathalye/proof-html#options), you can use:

swap_urls: |
  {"^(https://github.com/.*)#.*$": "\\1"}

Full Example

This is the entire .github/workflows/build.yml file for a GitHub Pages / Jekyll site.

name: CI
on:
  push:
  schedule:
    - cron: '0 8 * * 6'
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - uses: actions/setup-ruby@v1
        with:
          ruby-version: 2.7.x
      - uses: actions/cache@v2
        with:
          path: vendor/bundle
          key: ${{ runner.os }}-gems-${{ hashFiles('**/Gemfile.lock') }}
          restore-keys: |
            ${{ runner.os }}-gems-
      - run: |
          bundle config path vendor/bundle
          bundle install --jobs 4 --retry 3
      - run: bundle exec jekyll build
      - uses: anishathalye/proof-html@v2
        with:
          directory: ./_site
          enforce_https: false
          tokens: |
            {"https://github.com": "${{ secrets.GITHUB_TOKEN }}"}
          ignore_url: |
            http://www.example.com/
            https://en.wikipedia.org/wiki/Main_Page
          ignore_url_re: |
            ^https://twitter.com/
          swap_urls: |
            {"^https://www.anishathalye.com/": "/"}

Real-world examples

• missing-semester/.../links.yml
• dotfiles.github.com/.../build.yml

Running locally

You can build the Docker container locally with docker build . -t proof-html.

The GitHub Action is set up to pass arguments as strings through environment variables, where an argument like ignore_url is passed as INPUT_IGNORE_URL (capitalize and prepend INPUT_) to the Docker container, so you will need to do this translation yourself if you're running the Docker container locally. You can mount a local directory in the Docker container with the -v argument and pass the directory name as the INPUT_DIRECTORY argument. For example, if you compiled a site into the build directory, you can run:

docker run --rm \
    -e INPUT_DIRECTORY=build \
    -v "${PWD}/build:/build" \
    proof-html:latest

You can pass additional arguments as additional environment variables, e.g. -e INPUT_FORCE_HTTPS=0 or -e INPUT_TOKENS='{"https://github.com": "your-token-here"}'.

License

Copyright (c) Anish Athalye. Released under the MIT License. See LICENSE.md for details.