hyperlink-0.1.8 is not a library.

hyperlink

Very fast link checker for static sites.

Supports traversing file-system paths only, no arbitrary URLs.
- No support for the <base> tag.
- No support for external links. It does not know how to speak HTTP.
Does not honor robots.txt. A broken link is still broken for users even if not indexed by Google.
Does not parse CSS files, as broken links in CSS have not been a practical concern for us. We are concerned about broken link in the page content, not the chrome around it.
Only supports UTF-8 encoded HTML files.
Fast. docs.sentry.io produces 1.1 GB of HTML files. All alternatives we tried were slower than hyperlink on this site.

hyperlink handles this amount of data in 4 seconds on a MacBook Pro 2018.
Pay for what you need. By default, hyperlink checks for hard 404s in internal links only. Anything beyond that is opt-in. See Options for a list of features to enable.

Installation and Usage

# Check a folder of HTML
./hyperlink public/

# Also validate anchors
./hyperlink public/ --check-anchors

# src/ is a folder of Markdown. Show original Markdown file paths in errors
./hyperlink public/ --sources src/

Or as GitHub action:

- uses: untitaker/hyperlink@0.1.8
  with:
    args: public/ --sources src/

Or build from source by installing Rust and running cargo build --release.

Options

When invoked without options, hyperlink only checks for 404s of internal links. However, it can do more.

-j/--jobs: How many threads to spawn for parsing HTML. By default hyperlink will attempt to saturate your CPU.
--check-anchors: Opt-in, check for validity of anchors on pages. Broken anchors are considered warnings, meaning that hyperlink will exit 2 if there are only broken anchors but no hard 404s.
--sources: A folder of markdown files that were the input for the HTML hyperlink has to check. This is used to provide better error messages that point at the actual file to edit. hyperlink does very simple content-based matching to figure out which markdown files may have been involved in the creation of a HTML file.

Why not just crawl and validate links in Markdown at this point? Answer:
- There are countless of proprietary extensions to markdown out there for creating intra-page links that are generally not supported by link checking tools.
- The structure of your markdown content does not necessarily match the structure of your HTML (i.e. what the user actually sees). With this setup, hyperlink does not have to assume anything about your build pipeline.
--github-actions: Emit GitHub actions errors, i.e. add error messages in-line to PR diffs. This is only useful with --sources set.

Exit codes

exit 1: There have been errors (hard 404s)
exit 2: There have been only warnings (broken anchors)

Alternatives

wummel/linkchecker seems to be the most feature rich out of all, but was a non-starter due to performance. This applies to other countless link checkers we tried that are not mentioned here.
linkcheck is faster than linkchecker but still quite slow on large sites.

We tried linkcheck together with http-server on localhost, although that does not seem to be the bottleneck at all.
htmltest is one of the fastest linkcheckers we've tried (after disabling most checks to ensure feature parity with hyperlink), however is still slower than hyperlink in single-threaded mode (-j 1)
muffet seems to have similar performance as htmltest. We tested muffet with http-server and webfsd without noticing a change in timings.
liche seems to be closest in performance to hyperlink. hyperlink is generally faster, except on folders with many small files.

License