markdown-link-check

Extracts links from markdown texts and checks whether each link is alive (200 OK) or dead. mailto: links are validated with isemail.

Installation

To add the module to your project, run:

npm install --save-dev markdown-link-check

To install the command line tool globally, run:

npm install -g markdown-link-check

Run using Docker

Build a Docker image:

docker build --tag markdown-link-check .

Pipe your README.md file to docker run:

docker run --rm -i markdown-link-check < README.md

Run in a GitHub action

Please head on to github-action-markdown-link-check.

API

markdownLinkCheck(markdown, [opts,] callback)

Given a string containing markdown formatted text and a callback, extract all of the links and check if they're alive or dead. Call the callback with (err, results)

Parameters:

markdown string containing markdown formatted text.
opts optional options object containing any of the following optional fields:
- baseUrl the base URL for relative links.
- showProgressBar enable an ASCII progress bar.
- httpHeaders to apply URL specific headers, see example below.
- ignorePatterns an array of objects holding regular expressions which a link is checked against and skipped for checking in case of a match. Example: [{ pattern: /foo/ }]
- replacementPatterns an array of objects holding regular expressions which are replaced in a link with their corresponding replacement string. This behavior allows (for example) to adapt to certain platform conventions hosting the Markdown. Example: [{ pattern: /^.attachments/, replacement: "file://some/conventional/folder/.attachments" }]
- ignoreDisable if this is true then disable comments are ignored.
- retryOn429 if this is true then retry request when response is an HTTP code 429 after the duration indicated by retry-after header.
- aliveStatusCodes a list of HTTP codes to consider as alive. Example: [200,206]
callback function which accepts (err, results).
- err an Error object when the operation cannot be completed, otherwise null.
- results an array of objects with the following properties:
  - link the link provided as input
  - status a string set to either alive, ignored or dead.
  - statusCode the HTTP status code. Set to 0 if no HTTP status code was returned (e.g. when the server is down).
  - err any connection error that occurred, otherwise null.

Disable comments

You can write html comments to disable markdown-link-check for parts of the text.

 disables markdown link check.  reenables markdown link check.  disables markdown link check for the next line.  disables markdown link check for this line.

Examples

Module

Basic usage:

'use strict';

var markdownLinkCheck = require('markdown-link-check');

markdownLinkCheck('[example](http://example.com)', function (err, results) {
    if (err) {
        console.error('Error', err);
        return;
    }
    results.forEach(function (result) {
        console.log('%s is %s', result.link, result.status);
    });
});

With options, for example using URL specific headers:

'use strict';

var markdownLinkCheck = require('markdown-link-check');

markdownLinkCheck('[example](http://example.com)', { httpHeaders: [{ urls: ['http://example.com'], headers: { 'Authorization': 'Basic Zm9vOmJhcg==' }}] }, function (err, results) {
    if (err) {
        console.error('Error', err);
        return;
    }
    results.forEach(function (result) {
        console.log('%s is %s', result.link, result.status);
    });
});

Command Line Tool

The command line tool optionally takes 1 argument, the file name or http/https URL. If not supplied, the tool reads from standard input.

Check links from a markdown file hosted on the web

markdown-link-check https://github.com/tcort/markdown-link-check/blob/master/README.md

Check links from a local markdown file

markdown-link-check ./README.md

Check links from a local markdown folder (recursive)

find . -name \*.md -exec markdown-link-check {} \;

Check links from standard input

cat *.md | markdown-link-check

Usage

Usage: markdown-link-check [options] [filenameOrUrl]

Options:
  -p, --progress         show progress bar
  -c, --config [config]  apply a config file (JSON), holding e.g. url specific header configuration
  -q, --quiet            displays errors only
  -v, --verbose          displays detailed error information
  -a, --alive <code>     comma separated list of HTTP code to be considered as alive
  -r, --retry            retry after the duration indicated in 'retry-after' header when HTTP code is 429
  -h, --help             display help for command

Config file format

config.json:

ignorePatterns: An array of objects holding regular expressions which a link is checked against and skipped for checking in case of a match.
replacementPatterns: An array of objects holding regular expressions which are replaced in a link with their corresponding replacement string. This behavior allows (for example) to adapt to certain platform conventions hosting the Markdown.
httpHeaders: The headers are only applied to links where the link starts with one of the supplied URLs in the urls section.
retryOn429 if this is true then retry request when response is an HTTP code 429 after the duration indicated by retry-after header.
aliveStatusCodes a list of HTTP codes to consider as alive.

Example:

{
	"ignorePatterns": [
		{
			"pattern": "^http://example.net"
		}
	],
	"replacementPatterns": [
		{
			"pattern": "^.attachments",
			"replacement": "file://some/conventional/folder/.attachments"
		}
	],
	"httpHeaders": [
		{
			"urls": [
				"https://example.com"
			],
			"headers": {
				"Authorization": "Basic Zm9vOmJhcg==",
				"Foo": "Bar"
			}
		}
	],
  "retryOn429":true,
  "aliveStatusCodes":[200, 206]
}

Testing

npm test

License

See LICENSE.md

mneverov / markdown-link-check