hetianzhuo / robotskirt

A node wrapper for the awesome C markdown parser, sundown.

Robotskirt

Robotskirt is a Node.JS wrapper for the Sundown library.

It was inspired by the Redcarpet gem released by GitHub (the bindings to Ruby).
With the arrival of version 2 after much work, Robotskirt now mirrors every feature of Redcarpet, see below.
It even has additional features!

Full documentation can be found under the doc folder.
Robotskirt is distributed under the MIT license, see LICENSE.

Performance

Thanks to Sundown, Robotskirt is able to render markdown many times faster than other Markdown libraries.
With v2, efforts have been put to make it even lighter.

Sundown is well known for its security, speed and flexibility.
Robotskirt benefits from these features and tries to make the wrapping layer as thin as possible.

Robotskirt includes a small script to benchmark it against other popular markdown libraries.
It runs the official Markdown test suite 1000 times with each item.

Results on a Thinkpad T400 running Ubuntu 12.04 and Node 0.8.8 (currently the latest stable version):

$ node benchmark --bench
[1] robotskirt (reuse all) completed in 1354ms.
[2] robotskirt (convenience, reuse all) completed in 1353ms.
[3] robotskirt (new renderer and parser) completed in 3816ms.
[4] robotskirt (convenience, new parser) completed in 1534ms.
[5] marked completed in 3842ms.
[6] discount completed in 6025ms.
6 targets benchmarked successfully.

Install

The best way to install Robotskirt is by using NPM.
If you want to install it globally, remember to use sudo and -g.

npm install robotskirt

Important: you don't need to have Sundown installed: Robotskirt comes bundled
with a specific Sundown version. Just install Robotskirt as any other module.

Starting with v2.7, Robotskirt uses the preferred Node-GYP to compile.

Getting started

Currently there are two ways of using Robotskirt: normal and convenience.
We recommend you to learn both (hey, it's just two classes!) and see the examples.

The Normal Way

To parse Markdown, we first need a renderer. It takes the parsed Markdown,
and produces the final output (can be HTML, XHTML, ANSI, plain text, ...).

On most cases you will use Sundown's (X)HTML renderer:

var rs = require('robotskirt');
var renderer = new rs.HtmlRenderer();

Then, you make a parser that uses your renderer:

var parser = new rs.Markdown(renderer);

That's it! You can now start rendering your markdown:

parser.render('Hey, *this* is `code` with ÚŦF châracters!')
// '<p>Hey, <em>this</em> is <code>code</code> with ÚŦF châracters!</p>\n'

Always reuse your parsers/renderers! As you can see in the benchmark,
making and using the same pair to render everything saves a lot of time.
If you can't reuse them (for example, because the flags are supplied by the user),
consider using the convenience way.

OK. Want to customize the output a bit? Keep reading.

Using markdown extensions

Just using new Markdown(renderer) will parse pure markdown. However, you can have it
understand special extensions such as fenced code blocks, strikethrough, tables and more!

For example, the following will enable tables and autolinking:

var parser = new rs.Markdown(renderer, [rs.EXT_TABLES, rs.EXT_AUTOLINK]);

You can see the full list of extensions in the docs.

HTML rendering flags

Just as with extensions, you can pass certain flags to the HTML renderer.

For example, the following will use strict XHTML and skip all the <image> tags:

var renderer = new rs.HtmlRenderer([rs.HTML_USE_XHTML, rs.HTML_SKIP_IMAGES]);

You can see the full list of HTML flags in the docs.

UTF handling

Sundown is fully UTF-8 aware, both when handling and rendering.
Robotskirt will take care of the encoding and decoding tasks for you.

For more info about how UTF characters are treated, see the corresponding section in Sundown's README.

Custom renderers!

A renderer is just a set of functions.
Each time the parser finds a piece of Markdown it'll call the appropiate function in the renderer.
If the function is not set (undefined), the Markdown will be skipped or copied untouched.

Keep in mind, however, that you can't do asynchronous work in these functions.
This is because of Sundown's design.

Some use cases of custom renderers:

Highlighting code blocks

var renderer = new rs.HtmlRenderer();
renderer.blockcode = function (code, language) {
  if (language === undefined) {
    //No language was provided, don't highlight
    return '<pre>' + escapeHtml(code) + '</pre>';
  }
  return amazinglib.highlight(code, {"lang": language, "indent": 2});
};

You can see the full list of renderer functions in the docs.

Renderer from scratch

If you don't feel comfortable extending the HtmlRenderer class,
you can build a renderer from scratch by extending the base class: Renderer.
All renderers inherit from this class. It contains all functions set to undefined.

The Convenience Way

When you don't need custom renderers at all, you can just write:

var rs = require('robotskirt');
var parser = rs.Markdown.std();
parser.render(...);

That'll build a renderer/parser pair for you.
It's faster than building them manually, because it happens natively.

You can pass extension and HTML flags to it, respectively:

var parser = rs.Markdown.std([rs.EXT_TABLES, rs.EXT_AUTOLINK],
                             [rs.HTML_USE_XHTML, rs.HTML_SKIP_IMAGES]);
parser.render('This becomes http://autolink.ed in XHTML!');
// '<p>This becomes <a href="http://autolink.ed">http://autolink.ed</a> in XHTML!</p>\n'

Keep in mind that no other types of renderer can be chosen,
and you don't have access to the HTML renderer used.

Examples

TODO

Other utilities

Sundown (and Robotskirt) include some useful utilities. Code speaks by itself:

SmartyPants

Often used in conjunction with Markdown.
It makes "smart" punctuation. See more on its homepage.

> rs.smartypantsHtml('And I said ---to him--- "no worries"...');
'And I said —to him— “no worries”…'

Sundown implements SmartyPants with the same speed and security as usual.

Houdini, the escapist

> var rs = require('robotskirt')
> rs.houdini.escapeHTML('<b>Some code to escape.</b> <a title="Click me!">Me & you.</a>')
'&lt;b&gt;Some code to escape.&lt;&#47;b&gt; &lt;a title=&quot;Click me!&quot;&gt;Me &amp; you.&lt;&#47;a&gt;'
> rs.houdini.unescapeURL('Include+5%25+me%2Bin+a-query%3F+W%C3%ADth%C3%99TF%21')
'Include 5% me in a-query? WíthÙTF!'

Sundown's Autolink-er

//COMING SOON!

Version stuff

> rs.versions.sundown
<Version 1.16.0>
> rs.versions.robotskirt.toString() //String formatted version
'2.7.1'
> console.log('Sundown is at %s. Robotskirt is at %s',
... rs.versions.sundown, rs.versions.robotskirt);
Sundown is at 1.16.0. Robotskirt is at 2.7.1.
> rs.versions.sundown.minor
16
> rs.versions.robotskirt instanceof rs.Version
true