Referencing IETF sources

links to RFCs with a simple syntax -- [RFC-9110] and [RFC-2045-section-5.1]
links to HTTP headers regardless of current RFC that defines it -- [HTTP-Accept]

I wrote this simple extension when I was converting my ietfparse project from sphinx to mkdocs. It's documentation suite contains a lot of references to RFCs and HTTP headers. Sphinx supports referencing RFCs using :rfc: natively. The sphinxcontrib-httpdomain package adds support for HTTP headers and status codes using :http:. I wanted to bring this to mkdocs so that I didn't need to continuously add local references to RFCs.

Usage

This is the simple part. This extension recognizes two reference style link patterns and converts them to hyperlinks.

I haven't created a syntax that lets you control the link text yet. I may in the future but this met my immediate need.

Configuration

Simply add the library to your environment using your chosen package management mechanism. I use [hatch], so my pyproject.toml contains:

[tool.hatch.envs.default]
dependencies = [ "ietflinks", "mkdocs" ]

Then add ietflinks as a Markdown extension in your mkdocs.yml.

markdown_extensions:
  - ietflinks

That's it! A surprising bonus is that you don't have to think about the finer points of referencing IETF documents like which URL template to use for RFCs -- if you know what I am talking about, then you will appreciate this feature. It also takes care of knowing which RFC currently defines which HTTP header.

Customization

Since the Internet is always changing, you can add support for new HTTP headers or even override what I chose by default directly in your configuration file.

markdown_extension:
  - ietflinks:
    http_headers:
      overrides:
        content-md5: "https://www.rfc-editor.org/rfc/rfc2616.html#section-14.15"

You can also change the URL template if you find a reason to. It defaults to https://www.rfc-editor.org/rfc/rfc{rfc}. The {rfc} parameter is replaced by the RFC number.

markdown_extensions:
  - ietflinks:
    link_template: "https://tools.ietf.org/html/rfc{rfc}"

You can also disable processing of either syntax by setting the process property to false.

markdown_extensions:
  - ietflinks:
    rfc:
      process: false

When a reference style is disabled, the reference is replaced by its text without the brackets. So [RFC-9110] would be replaced by <span>RFC-9110</span>. You can enable pure passthrough functionality by setting process to null.

A json schema for the configuration is available at the root of the repository.

https://raw.githubusercontent.com/dave-shawley/pymdown-ietf/refs/heads/main/config-schema.json