Markdown Extension for PHP

yiipress/markdown is a native PHP extension for rendering Markdown to HTML with bundled MD4C.

Warning

This package is deprecated in favor of https://github.com/iliaal/mdparser/.

Requirements

• PHP 8.2 - 8.5.
• PIE to install the extension.
• On Linux and macOS: C compiler, and make.

Prebuilt Windows DLLs are attached to GitHub releases.

Install

Install the extension with PIE:

pie install yiipress/markdown

Then require the extension from applications that use it:

composer require ext-markdown:*

Usage

Create a renderer once, then call render() for each Markdown string:

use YiiPress\Markdown\MarkdownOptions;
use YiiPress\Markdown\MarkdownRenderer;

$renderer = new MarkdownRenderer(new MarkdownOptions(
    tables: true,
    tasklists: true,
    htmlBlocks: true,
    htmlSpans: true,
));

echo $renderer->render("# Hello");

MarkdownOptions is immutable. Pass options to the constructor to choose the Markdown features accepted by the parser and the HTML renderer flags used for output.

Defaults enable common extensions:

• tables
• strikethrough
• task lists
• URL, email, and WWW autolinks
• whitespace collapse
• hard soft breaks
• footnotes
• admonitions
• raw HTML blocks and spans

Disable raw HTML by turning off both HTML options:

$renderer = new MarkdownRenderer(new MarkdownOptions(
    htmlBlocks: false,
    htmlSpans: false,
));

Optional MD4C extensions can be enabled individually:

$renderer = new MarkdownRenderer(new MarkdownOptions(
    latexMath: true,
    wikilinks: true,
    spoilers: true,
    superscripts: true,
    subscripts: true,
    highlight: true,
));

MD4C Constants

Most applications should use MarkdownOptions. The extension also exposes MD4C's raw constants when you need to inspect the generated parser bitmask, store low-level settings, or pass HTML renderer flags directly.

• YiiPress\Markdown\Flag contains parser feature flags, such as Flag::TABLES, Flag::NO_HTML, and Flag::FOOTNOTES.
• YiiPress\Markdown\Dialect contains MD4C dialect presets, such as Dialect::COMMONMARK and Dialect::GITHUB.
• YiiPress\Markdown\HtmlFlag contains flags for MD4C's HTML renderer, such as HtmlFlag::XHTML and HtmlFlag::VERBATIM_ENTITIES.

Use HtmlFlag values with MarkdownOptions::$rendererFlags:

use YiiPress\Markdown\HtmlFlag;
use YiiPress\Markdown\MarkdownOptions;
use YiiPress\Markdown\MarkdownRenderer;

$renderer = new MarkdownRenderer(new MarkdownOptions(
    rendererFlags: HtmlFlag::XHTML | HtmlFlag::VERBATIM_ENTITIES,
));

Use Flag values when you need to inspect or compare parser settings:

use YiiPress\Markdown\Flag;
use YiiPress\Markdown\MarkdownOptions;

$options = new MarkdownOptions(htmlBlocks: false, htmlSpans: false);
$parserFlags = $options->toParserFlags();

if (($parserFlags & Flag::NO_HTML) === Flag::NO_HTML) {
    // Raw HTML blocks and spans are disabled.
}

Use Dialect values when interoperating with code that expects MD4C's dialect bitmasks:

use YiiPress\Markdown\Dialect;

$githubFlags = Dialect::GITHUB;

Scope

Version 1 is Markdown-to-HTML only. It intentionally does not expose a PHP callback or event wrapper around MD4C's lower-level md_parse() API.

Compared with mdparser, this package prioritizes MD4C feature coverage and medium/large input performance. It does not add mdparser-only features such as smart punctuation, heading anchors, source positions, nofollow links, or tag filtering.

Development

Run the PHPT suite in Docker:

make test

Show the currently bundled MD4C revision:

make md4c-version

Check whether the configured upstream MD4C ref has changed:

make md4c-check-upgrade

Update the vendored MD4C files:

make md4c-upgrade

By default, MD4C targets use upstream master. Pass MD4C_REF to check or upgrade to another branch, tag, or commit:

make md4c-upgrade MD4C_REF=release-0.5.3

Bundled MD4C

This package vendors MD4C source code under third_party/md4c/. MD4C is licensed under the MIT license; its license notice is included at third_party/md4c/LICENSE.md.

Credits

This extension was inspired by eklausme/php-md4c, an earlier PHP extension wrapper for MD4C.