league/commonmark is a PHP-based Markdown parser created by Colin O'Dell which supports the full CommonMark spec. It is based on the CommonMark JS reference implementation by John MacFarlane (@jgm).

• Fully support the CommonMark spec (100% compliance)
• Match the C and JavaScript implementations of CommonMark to make a logical and similar API
• Continuously improve performance without sacrificing quality or compliance
• Provide an extensible parser/renderer which users may customize as needed

This project can be installed via Composer:

$ composer require league/commonmark

Note: See Versioning for important information on which version constraints you should use.

The CommonMarkConverter class provides a simple wrapper for converting CommonMark to HTML:

use League\CommonMark\CommonMarkConverter;

$converter = new CommonMarkConverter();
echo $converter->convertToHtml('# Hello World!');

// <h1>Hello World!</h1>

⚠️ Security warning: If you will be parsing untrusted input from users, please consider setting the html_input and allow_unsafe_links options. See https://commonmark.thephpleague.com/security/ for more details.

The actual conversion process requires two steps:

1. Parsing the Markdown input into an AST
2. Rendering the AST document as HTML

Although the CommonMarkConverter wrapper simplifies this process for you, advanced users will likely want to do this themselves:

use League\CommonMark\CommonMarkConverter;
use League\CommonMark\Environment;

// Obtain a pre-configured Environment with all the CommonMark parsers/renderers ready-to-go
$environment = Environment::createCommonMarkEnvironment();

// Optional: Add your own parsers, renderers, extensions, etc. (if desired)
// For example:  $environment->addInlineParser(new TwitterHandleParser());

// Define your configuration:
$config = [
  'html_input' => 'escape',
  'renderer' => [
    // To configure GitHub style newlines to create line breaks:
    'soft_break' => "<br />\n",
  ],
];

// Create the converter
$converter = new CommonMarkConverter($config, $environment);

// Here's our sample input
$markdown = '# Hello World!';

// Let's render it!
echo $converter->convertToHtml($markdown);

// The output should be:
// <h1>Hello World!</h1>

This approach allows you to access/modify the AST before rendering it.

You can also add custom parsers/renderers by registering them with the Environment class. The documentation provides several customization examples such as:

• Parsing Twitter handles into profile links
• Converting smilies into emoticon images

You can also reference the core CommonMark parsers/renderers as they use the same functionality available to you.

Documentation can be found at commonmark.thephpleague.com.

• CakePHP 3
• Drupal 7 & 8
• Laravel 4 & 5
• Sculpin
• Symfony 2 & 3
• Symfony 4
• Twig Markdown extension
• Twig-based renderer
• Twig filter and tag

The PHP League offers useful extensions that add extra syntax and features:

• league/commonmark-extras - Bundles the extensions below into a single dependency for convenience
  • league/commonmark-ext-autolink - Extension for league/commonmark which autolinks URLs, emails, and (optionally) @-mentions
  • league/commonmark-ext-smartpunct - Intelligently converts ASCII quotes, dashes, and ellipses to their Unicode equivalents
• league/commonmark-ext-inlines-only - Renders inline text without paragraph tags or other block-level elements

You can add them to your project or use them as examples to develop your own custom features.

Custom parsers/renderers can be bundled into extensions which extend CommonMark. Here are some that you may find interesting:

• CommonMark Table Extension - Adds the ability to create tables in CommonMark documents.
• CommonMark Attributes Extension - Adds a syntax to define attributes on the various HTML elements.
• Alt Three Emoji An emoji parser for CommonMark.
• uafrica/commonmark-ext - Adds strikethrough support.
• Sup Sub extensions - Adds support of superscript and subscript (<sup> and <sub> HTML tags)

If you build your own, feel free to submit a PR to add it to this list!

Check out the other cool things people are doing with league/commonmark: https://packagist.org/packages/league/commonmark/dependents

This project aims to fully support the entire CommonMark spec. Other flavors of Markdown may work but are not supported. Any/all changes made to the spec or JS reference implementation should eventually find their way back into this codebase.

league/commonmark 0.15.5 and higher supports version 0.28 of the CommonMark spec.

(This package is not part of CommonMark, but rather a compatible derivative.)

$ ./vendor/bin/phpunit

This will also test league/commonmark against the latest supported spec.

You can compare the performance of league/commonmark to other popular parsers by running the included benchmark tool:

$ ./tests/benchmark/benchmark.php

SemVer will be followed closely. 0.x.0 versions will introduce breaking changes to the codebase, so be careful which version constraints you use. It's highly recommended that you use Composer's caret operator to ensure compatibility; for example: ^0.18. This is equivalent to >=0.18.0 <0.19.0.

0.x.y releases should not introduce breaking changes to the codebase; however, they might change the resulting AST or HTML output of parsed Markdown (due to bug fixes, minor spec changes, etc.) As a result, you might get slightly different HTML, but any custom code built onto this library will still function correctly.

If you're only using the CommonMarkConverter class or ConverterInterface to convert Markdown (no other class references, custom parsers, etc.), then it should be safe to use a broader constraint like ~0.18, >0.18, etc. I personally promise to never break this specific class in any future 0.x release.

While this package does work well, the underlying code should not be considered "stable" yet. The original spec and JS parser may undergo changes in the near future which will result in corresponding changes to this code. Any methods tagged with @api are not expected to change, but other methods/classes might.

Major release 1.0.0 will be reserved for when either the CommonMark spec or this project are considered stable (see outstanding CommonMark spec issues). 0.x.y will be used until that happens.

If you encounter a bug in the spec, please report it to the CommonMark project. Any resulting fix will eventually be implemented in this project as well.

For now, I'd like to maintain similar logic as the JS reference implementation until everything is stable. I'll gladly accept any contributions which:

• Mirror fixes made to the reference implementation
• Optimize existing methods or regular expressions
• Fix issues with adhering to the spec examples

Major refactoring should be avoided for now so that we can easily follow updates made to the reference implementation. This restriction will likely be lifted once the CommonMark specs and implementations are considered stable.

Please see CONTRIBUTING for additional details.

If you discover any security related issues, please email your report privately to [email protected] instead of using the issue tracker.

• Colin O'Dell
• John MacFarlane
• All Contributors

This code is a port of the CommonMark JS reference implementation which is written, maintained and copyrighted by John MacFarlane. This project simply wouldn't exist without his work.

Also a huge thank you to JetBrains for supporting the development of this project with complimentary PhpStorm licenses.

league/commonmark is licensed under the BSD-3 license. See the LICENSE file for more details.

This project is primarily maintained by Colin O'Dell. Members of the PHP League Leadership Team may occasionally assist with some of these duties.