parsedown README

The project's README from github.com/erusev/parsedown. As one markdown file: README.md.

Parsedown

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Better Markdown Parser in PHP — demo

Features

Installation

Install the composer package:

composer require erusev/parsedown

Or download the latest release and include Parsedown.php

Example

$Parsedown = new Parsedown();

echo $Parsedown->text('Hello _Parsedown_!'); # prints: <p>Hello <em>Parsedown</em>!</p>

You can also parse inline markdown only:

echo $Parsedown->line('Hello _Parsedown_!'); # prints: Hello <em>Parsedown</em>!

More examples in the wiki and in this video tutorial.

Security

Parsedown is capable of escaping user-input within the HTML that it generates. Additionally Parsedown will apply sanitisation to additional scripting vectors (such as scripting link destinations) that are introduced by the markdown syntax itself.

To tell Parsedown that it is processing untrusted user-input, use the following:

$Parsedown->setSafeMode(true);

If instead, you wish to allow HTML within untrusted user-input, but still want output to be free from XSS it is recommended that you make use of a HTML sanitiser that allows HTML tags to be whitelisted, like HTML Purifier.

In both cases you should strongly consider employing defence-in-depth measures, like deploying a Content-Security-Policy (a browser security feature) so that your page is likely to be safe even if an attacker finds a vulnerability in one of the first lines of defence above.

Safe mode does not necessarily yield safe results when using extensions to Parsedown. Extensions should be evaluated on their own to determine their specific safety against XSS.

Escaping HTML

WARNING: This method is not safe from XSS!

If you wish to escape HTML in trusted input, you can use the following:

$Parsedown->setMarkupEscaped(true);

Beware that this still allows users to insert unsafe scripting vectors, ex: [xss](javascript:alert%281%29).

Questions

How does Parsedown work?

It tries to read Markdown like a human. First, it looks at the lines. It’s interested in how the lines start. This helps it recognise blocks. It knows, for example, that if a line starts with a - then perhaps it belongs to a list. Once it recognises the blocks, it continues to the content. As it reads, it watches out for special characters. This helps it recognise inline elements (or inlines).

We call this approach "line based". We believe that Parsedown is the first Markdown parser to use it. Since the release of Parsedown, other developers have used the same approach to develop other Markdown parsers in PHP and in other languages.

Is it compliant with CommonMark?

It passes most of the CommonMark tests. Most of the tests that don't pass deal with cases that are quite uncommon. Still, as CommonMark matures, compliance should improve.

Who uses it?

Laravel Framework, Bolt CMS, Grav CMS, Herbie CMS, Kirby CMS, October CMS, Pico CMS, Statamic CMS, phpDocumentor, RaspberryPi.org, Symfony Demo and more.

How can I help?

Use it, star it, share it and if you feel generous, sponsor me.

What else should I know?

I also make Nota — a notes app designed for local Markdown files.

parsedown (erusev/parsedown)

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15.1K ·GitHub
What is this?Parsedown is a Markdown parser library for PHP: you feed it Markdown text and it converts it into HTML.
Is it a library I call from my PHP code, or an app I run?It is a library: you include it in a PHP project and call it wherever your code needs Markdown turned into HTML — there is no interface or app to run.
How do I use it in my code?You create a Parsedown instance and call its text() method with a Markdown string; it returns the rendered HTML. That is the basic usage shown in the README.
Can I safely render Markdown submitted by my site's visitors?Not out of the box — the README warns outright that its default method is not safe from XSS. A safe mode escapes HTML, but the README cautions it still allows unsafe scripting vectors.
Who uses it in real projects?It is widely adopted: Laravel Framework, Bolt CMS, Grav CMS, Kirby CMS, October CMS, Pico CMS, Statamic CMS, phpDocumentor, RaspberryPi.org and the Symfony Demo all use it.
Does it pass the CommonMark test suite?Mostly: Parsedown passes most of the CommonMark tests, and the ones it fail deal with uncommon cases. The author expects compliance to improve as the spec matures.
How does Parsedown parse Markdown differently from other parsers?It reads Markdown like a human: how lines start reveals blocks (a line beginning with a - may belong to a list), then it watches for special characters to spot inline elements. The author calls this the 'line based' approach and says it was the first parser to use it, with others following in PHP and beyond.
What else has the author built?The author also makes Nota, a notes app designed for local Markdown files.
What are similar projects?marked, markdown-it, nom, lexer, liteparse, PHP-Parser, turndown, go
Creator
erusev
Size
1.5 MB
Stars
15.1K
Age
13y
Commits · 90 Days