Accessing Collections - Building a Custom Client #

In this guide, we will build an HTTP client from scratch to perform CRUD as well as listen for events from a Collection.


Most REST clients should work with Deployd Collections right away, though Deployd does not strictly follow REST. For example, Backbone.js and AngularJS's HTTP utilities work with Deployd without modification.

WebSockets #

To fully implement the Collection API, a client must be compatible with WebSockets and Socket.IO specifically. Clients are responsible for sending heartbeat information as well as reconnecting in the case of unexpected disconnects.

Building a Node.js Client #

The following is implemented in Node.js, but the basic idea can be applied to any language or platform.

Basics #

All we need to create a collection client is a constructor and a single method for making requests.

var request = require('request');

function Collection(url) {
  this.url = url

Collection.prototype.request = function (options, fn) {
  var url = this.url;
  options.url = url + (options.url || '');  
  request(options, function (err, res, body) {
    if(res.statusCode >= 400) {
      err = body || {message: 'an unknown error occurred'};
      return fn(err);

    fn(null, body);

Now we can construct new collections by passing the URL as the only argument to our constructor.

var c = new Collection('');

c.request({url: '?done=false'}, function(err, todos) {
  console.log(todos); // [...]

We can add an object to our collection by passing an object as the json body and setting the method to "POST".

var todo = {
  title: 'wash the car'

c.request({json: todo, method: 'POST'}, function(err, todo) {
  console.log(todo); // {id: '...', ...}

To update an object we just need to set the method to "PUT".

var todo = {
  id: '06a5254f11ff7853',
  done: true

c.request({json: todo, method: 'PUT'}, function(err, todo) {
  console.log(todo); // {id: '...', ...}

Deleting an object requires an ID and the method must be set to "DELETE".

var id = '06a5254f11ff7853';

c.request({url: '/' + id, method: 'DELETE'}, function(err, todo) {
  console.log(err); // null - if no error occurred

Listening to Events #

The simplest way to listen events is to use a Socket.IO client. You can find a list of clients here.

Using the node.js Socket.IO client, we can create a socket by connecting to our deployed app. Then calling the socket's on() method to listen to a custom event emitted by a collection.

var io = require('');
var socket = io.connect('');

socket.on('my event', function (data) {
  console.log(data); // emit()ed from the server