ℹ️ Fork of tcort repository (version 3.8.3), with several improvements:

• completely rewritten in typescript
• see CHANGELOG.md since v3.8.3 to get full list of improvements (multiple inputs support, cache, concurrency, statistics, debug traces,...)

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 @boillodmanuel/markdown-link-check

To install the command line tool globally, run:

npm install -g @boillodmanuel/markdown-link-check

Usage

Using from Command line tool (CLI)

The command line tool checks markdown links from 1 or several files or URLs or from standard input.

Note: You can either use this library from a javascript/typescript project (as a node dependency) or from command line. To run the command line, type:

• markdown-link-check README.md if you installed it globally
• npx markdown-link-check README.md if you installed it as a project dependency.

Documentation

Usage: markdown-link-check [options] [filenameOrUrls...]

Argument:

• [filenameOrUrls...]: one or several files or URLs. If absent, process stdin

Options:

Options specific to command line:

• -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
• --print-summary: print total number of inputs and links process with details about link status (alive, ignored, dead, error)
• --print-cache-stats prints cache usage (hits and misses).
• --print-long-checks prints links that took more than given delay to verify. Default delay is 5000, configure it with --long-checks-max-duration option.
• --long-checks-max-duration configure delay for long check. Default is 5000.
• -h, --help display help for command

Options that override configuration file:

• -a, --alive <codes> comma separated list of HTTP code to be considered as alive
• --retry-on-error retry after the an error
• --retry-on-429 retry after the duration indicated in 'retry-after' header when HTTP code is 429
• --timeout <duration> timeout in zeit/ms format. (e.g. 2000ms, 20s, 1m). Default is 10s.
• -e, --fileEncoding <encoding> set file enconding. Default is utf-8.
• -d, --debug displays debug traces (very verbose)

Examples

Simple examples:

# 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 multiples markdown file
markdown-link-check ./README.md ./CHANGELOG.md

# Check links from stdin
curl -s https://github.com/tcort/markdown-link-check/blob/master/README.md | markdown-link-check

Advanced examples:

Check links for each files

# Check links from a local markdown folder (recursive)
find . -name \*.md -exec markdown-link-check {} \;

Check links for all files (run a single process which can leverage cache)

# Add files in a bash array (using -print0 to support file names with space or special characters)
FILES=()
while IFS=  read -r -d 

\0' FILE; do
    FILES+=("$FILE")
done < <(find . -name '*.md' ! -path './node_modules/*' -print0)
markdown-link-check --print-summary "${FILES[@]}"

Using from a node project

This part is not documented. The best way to kwow how to use this library from code is to look at run function in /src/bin/markdown-link-check.ts` which is the entry point of the command line utility.

Configuration

You can configure the processing with using a configuration file described below.

Configuration file format

File config.json attributes per category:

Input content:

• fileEncoding: set file enconding. Default is utf-8.

Link management:

• 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.
• resolveAbsolutePathWithBaseUrl: if true links with absolute path (e.g. /section/page1.md) are resolved from baseUrl (see below) where as links with with relative path (e.g. ./page2.md) are resolved from current url/path. This option reflects some wiki behavior. Default is false.
• baseUrl: base url/path used to resolved links with absolute path if resolveAbsolutePathWithBaseUrl is true. The value should starts with file://, http:// or https://.

Error management:

• timeout timeout in zeit/ms format. (e.g. "2000ms", 20s, 1m). Default 10s.
• retryOnError if this is true then retry after an error.
• retryOn429 if this is true then retry request when response is an HTTP code 429 after the duration indicated by the retry-after response header or by the fallbackRetryDelay option.
• retryCount the number of retries to be made on a 429 response. Default 2.
• fallbackRetryDelay the delay in zeit/ms format. (e.g. "2000ms", 20s, 1m) for retries on a 429 response when no retry-after header is returned or when it has an invalid value. Default is 5s.
• aliveStatusCodes a list of HTTP codes to consider as alive.

Concurrency:

• concurrentFileCheck: Number of file or url processed concurrently. Default is 2.
• concurrentCheck: Number of links processed concurrently for a single file or url. Default is 2.

Debug:

• debug displays debug traces
• debugToStdErr redirect debug trace to sterr instead of stdout

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"
      }
    }
  ],
  "timeout": "20s",
  "retryOn429": true,
  "retryCount": 5,
  "fallbackRetryDelay": "30s",
  "aliveStatusCodes": [200, 206],
  "concurrentFileCheck": 5,
  "concurrentCheck": 2,
  "fileEncoding": "utf-8",
  "resolveAbsolutePathWithBaseUrl": true,
  "baseUrl": "/var/wiki",
  "debug": false,
  "debugToStdErr": false,
}

Ignore some links from markdown

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.

Documentation from original repository

Note: The documentation in this section comes from original repository and is not maintained in this fork but kept for information. this library

Run using Docker

Docker images are built with each release. Use the stable tag for the current stable release.

Add current directory with your README.md file as read only volume to docker run:

docker run -v ${PWD}:/tmp:ro --rm -i ghcr.io/tcort/markdown-link-check:stable /tmp/README.md

Alternatively, if you wish to target a specific release, images are tagged with semantic versions (i.e. 3, 3.8, 3.8.3)

Run in a GitHub action

Note: Github action is not maintained in this fork.

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

Run in other tools

• Mega-Linter: Linters aggregator including 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.
  • timeout timeout in zeit/ms format. (e.g. "2000ms", 20s, 1m). Default 10s.
  • 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.
  • retryCount the number of retries to be made on a 429 response. Default 2.
  • fallbackRetryDelay the delay in zeit/ms format. (e.g. "2000ms", 20s, 1m) for retries on a 429 response when no retry-after header is returned or when it has an invalid value. Default is 60s.
  • 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.

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);
    });
});

Test command line

npx markdown-link-check test/file1.md
npx markdown-link-check --inputs test/file1.md test/file2.md

License

See LICENSE.md