500 Pagelet

[![Version npm][version]](http://browsenpm.org/package/500-pagelet)[![Build Status][build]](https://travis-ci.org/bigpipe/500-pagelet)[![Dependencies][david]](https://david-dm.org/bigpipe/500-pagelet)[![Coverage Status][cover]](https://coveralls.io/r/bigpipe/500-pagelet?branch=master)

[version]: http://img.shields.io/npm/v/500-pagelet.svg?style=flat-square
[build]: http://img.shields.io/travis/bigpipe/500-pagelet/master.svg?style=flat-square
[david]: https://img.shields.io/david/bigpipe/500-pagelet.svg?style=flat-square
[cover]: http://img.shields.io/coveralls/bigpipe/500-pagelet/master.svg?style=flat-square

This Pagelet is responsible for displaying server errors. By
default the 500 Pagelet is provided with [BigPipe]. However, if you
need a custom 500 you can extend this Pagelet. For example to change
the default view.

Installation

The 500 Pagelet is distributed through the node package manager (npm).

``
npm install --save 500-pagelet
`

Support

Got stuck? Or can't wrap your head around a concept or just want some feedback,
we got a dedicated IRC channel for that on Freenode:

- IRC Server: irc.freenode.net
- IRC Room: #bigpipe

Still stuck? Create an issue. Every question you have is a bug in our
documentation and that should be corrected. So please, don't hesitate to create
issues, many of them.

$3

In this example the 500 Pagelet is extended with a custom view.
[BigPipe] will automatically discover this extended version
if it is provided to [BigPipe] alongside the other pagelets.
Note that the enviroment variable can be overruled to manage the
data that is displayed.

`js
'use strict';

//
// Extend the 500 Pagelet with a custom view.
//
var Fivehundred = require('500-pagelet').extend({
view: '/path/to/my/custom-view.html', // your custom layout
env: 'development' // defaults to process.env.NODE_ENV
});

//
// Initialise BigPipe server.
//
var pipe = require('bigpipe').createServer(2000, {
pagelets: [ Fivehundred, ... ]
});
`

$3

The following methods are available on the 500 Pagelet instance. Most are
only used internally. There is rarely a reason to call these methods.

#### new Fivehundred()

public, _returns Pagelet_.

The 500 constructor expects several options to be provided, these
include: req, res and pipe. The last option is a reference
to the [BigPipe] instance, mainly to ensure the same [Temper]
instance is re-used. All code examples assume your file is setup as:

`js
'use strict';

var Fivehundred = require('500-pagelet');
, fivehundred = new Fivehundred({ options }, new Error('failure'));
`

#### Bootstrap.get()

private, _returns Pagelet_.

Extracts the data from the provided Error to render the template.
If the environment is _production_ the Error.stack will not be
provided to the template.

`js
fivehundred.get(function render(error, data) {
// provide data to pagelet.render
});
`

Debugging

The library makes use the diagnostics module from Pagelet.
To display the 500 Pagelet specific debug messages, supply the
following before running the program or

`bash
DEBUG=pagelet:500 node ...
`

Testing

Tests are automatically run on [Travis CI] to ensure that everything is
functioning as intended. For local development we automatically install a
[pre-commit] hook that runs the npm test command every time you commit changes.
This ensures that we don't push any broken code in to this project.

To run tests locally, make sure the development dependencies are installed.

`bash
npm test
npm run coverage
``

License

500-pagelet is released under MIT.

[BigPipe]: http://bigpipe.io/
[Travis CI]: http://travisci.org
[Temper]: http://github.com/bigpipe/temper
[pre-commit]: http://github.com/observing/pre-commit