express-resource

Express Resource

express-resource provides resourceful routing to express.

Installation

npm:

$ npm install express-resource

Usage

To get started simply require('express-resource'), and this module will monkey-patch Express, enabling resourceful routing by providing the app.resource() method. A "resource" is simply an object, which defines one of more of the supported "actions" listed below:

exports.index = function(req, res){
  res.send('forum index');
};

exports.new = function(req, res){
  res.send('new forum');
};

exports.create = function(req, res){
  res.send('create forum');
};

exports.show = function(req, res){
  res.send('show forum ' + req.params.forum);
};

exports.edit = function(req, res){
  res.send('edit forum ' + req.params.forum);
};

exports.update = function(req, res){
  res.send('update forum ' + req.params.forum);
};

exports.destroy = function(req, res){
  res.send('destroy forum ' + req.params.forum);
};

The app.resource() method returns a new Resource object, which can be used to further map pathnames, nest resources, and more.

var express = require('express')
  , Resource = require('express-resource')
  , app = express.createServer();

app.resource('forums', require('./forum'));

Default Action Mapping

Actions are then mapped as follows (by default), providing req.params.forum which contains the substring where ":forum" is shown below:

GET     /forums              ->  index
GET     /forums/new          ->  new
POST    /forums              ->  create
GET     /forums/:forum       ->  show
GET     /forums/:forum/edit  ->  edit
PUT     /forums/:forum       ->  update
DELETE  /forums/:forum       ->  destroy

Top-Level Resource

Specify a top-level resource by omitting the resource name:

app.resource(require('./forum'));

Top-level actions are then mapped as follows (by default):

GET     /                 ->  index
GET     /new              ->  new
POST    /                 ->  create
GET     /:id              ->  show
GET     /:id/edit         ->  edit
PUT     /:id              ->  update
DELETE  /:id              ->  destroy

Auto-Loading

Resources have the concept of "auto-loading" associated data. For example we can pass a "load" property along with our actions, which should invoke the callback function with an error, or the object such as a User:

  User.load = function(id, fn) {
    fn(null, users[id]);
  };

  // or
  
  User.load = function(req, id, fn) {
    fn(null, users[id]);
  };

  app.resource('users', { show: ..., load: User.load });
  

With the auto-loader defined, the req.user object will be available now be available to the actions automatically. We may pass the "load" option as the third param as well, although this is equivalent to above, but allows you to either export ".load" along with your actions, or passing it explicitly:

 app.resource('users', require('./user'), { load: User.load });

Finally we can utilize the Resource#load(fn) method, which again is functionally equivalent:

 var user = app.resource('users', require('./user'));
 user.load(User.load);

This functionality works when nesting resources as well, for example suppose we have a forum, which contains threads, our setup may look something like below:

  var forums = app.resource('forums', require('resources/forums'), { load: Forum.get });
  var threads = app.resource('threads', require('resources/threads'), { load: Thread.get });

  forums.add(threads);

Now when we request GET /forums/5/threads/12 both the req.forum object, and req.thread will be available to thread's show action.

Content-Negotiation

Currently express-resource supports basic content-negotiation support utilizing extnames or "formats". This can currently be done two ways, first we may define actions as we normally would, and utilize the req.format property, and respond accordingly. The following would respond to GET /pets.xml, and GET /pets.json.

  var pets = ['tobi', 'jane', 'loki'];

  exports.index = function(req, res){
    switch (req.format) {
      case 'json':
        res.send(pets);
        break;
      case 'xml':
        res.send('<pets>' + pets.map(function(pet){
          return '<pet>' + pet + '</pet>';
        }).join('') + '</pets>');
        break;
      default:
        res.send(406);
    }
  };

The following is equivalent, however we separate the logic into several callbacks, each representing a format.

 exports.index = {
   json: function(req, res){
     res.send(pets);
   },

   xml: function(req, res){
     res.send('<pets>' + pets.map(function(pet){
       return '<pet>' + pet + '</pet>';
     }).join('') + '</pets>');
   }
 };

We may also provide a default format, invoked when either no extension is given, or one that does not match another method is given:

 exports.default = function(req, res){
   res.send('Unsupported format "' + req.format + '"', 406);
 };

To assign a default format to an existing method, we can provide the format option to the resource. With the following definition both GET /users/5 and GET /users/5.json will invoke the show.json action, or show with req.format = 'json'.

 app.resource('users', actions, { format: 'json' });

Running Tests

First make sure you have the submodules:

$ git submodule update --init

Then run the tests:

$ make test

License

The MIT License

Copyright (c) 2010-2011 TJ Holowaychuk <[e-mail]>
Copyright (c) 2011 Daniel Gasienica <[e-mail]>

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
'Software'), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.