markdown-link-check

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.
• 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.

<!-- markdown-link-check-disable --> disables markdown link check. <!-- markdown-link-check-enable --> reenables markdown link check. <!-- markdown-link-check-disable-next-line --> disables markdown link check for the next line. <!-- markdown-link-check-disable-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 configuration file (JSON)
    -q, --quiet            display errors only
    -v, --verbose          displays detailed error information 
    -h, --help             output usage information

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.

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"
			}
		}
	]
}

Testing

npm test

License

See LICENSE.md

Changelog

Version 3.8.2

• update dependencies