Linkchecker for Markdown-based static generated sites

Blazing-fast (10000 Markdown files per second) Python asyncio / aiohttp based simple check of links in Markdown .md files only. This tool is very helpful for large Markdown-based Jekyll and Hugo sites as well as Markdown-based MkDocs documentation projects. It is very fast and simple--it's what we use to check https://www.scivision.dev

Install

for latest release:

python -m pip install linkcheckmd

or for latest development version.

git clone https://github.com/scivision/linkchecker-markdown

pip install -e linkchecker-markdown

Usage

The static site generator does NOT have to be running for these tests. This program looks at the Markdown .md files directly.

If any local or remote links are determined to be missing, the following happens:

• the file containing the bad link and the link is printed to "stdout"
• the program will exit with code 22 instead of 0 after all files are checked

The bad links are printed to stdout since the normal operation of this program is to check for errors. Due to the fast, concurrent checking and numerous pages checked, there may be diagnostics printed to stderr. That way library error messages can be kept separate from the missing page locations printed on stdout.

The examples assume webpage Markdown files have top-level directory ~/web. If using the linkchecker on an MkDocs documentation project, Markdown files are typically found in a ~/docs directory.

Python code

import linkcheckmd as lc

lc.check_links("~/web")

Command-line

This program may be invoked by either:

linkcheckMarkdown

or

python -m linkcheckmd

• Jekyll

  python -m linkcheckmd ~/web/_posts

• Hugo

  python -m linkcheckmd ~/web/content

• MkDocs Documentation

  python -m linkcheckmd ~/docs

The -v --verbose options prints the URLs as they are checked. Observe that URLs from different markdown files are interleaved, showing the asynchronous nature of this program.

Benchmark

For benchmarking and reference, we include a synchronous Requests-based method. For a website with 100+ pages, compare times of:

Git precommit

See ./examples/pre-commit script for a Git hook pre-commit Python script.

Tox and CI

This program can also be used as a check for bad links during continuous integration testing or when using tox.

Alternatives

Strict anti-leeching methods can cause false positives with this and other link checking programs.

Alternative solutions include:

• asyncio-based web browser interface like Arsenic
• Go-based htmltest.
• GitHub Action for checking links in Markdown files.
• Netlify link-check plugin
• LinkChecker.py: too many false positives/negatives, very slow and only works with HTML.