jsforce/lib/api/streaming.js

Salesforce API Library for JavaScript

/**
 * @file Manages Streaming APIs
 * @author Shinichi Tomita <shinichi.tomita@gmail.com>
 */

var events = require('events'),
    util   = require('util'),
    Faye   = require('faye');

/**
 * Streaming API topic class
 *
 * @class Streaming~Topic
 * @param {Streaming} steaming - Streaming API object
 * @param {String} name - Topic name
 */
var Topic = module.exports = function(streaming, name) {
  this._streaming = streaming;
  this.name = name;
};

/**
 * @typedef {Object} Streaming~StreamingMessage
 * @prop {Object} event
 * @prop {Object} event.type - Event type
 * @prop {Record} sobject - Record information
 */
/**
 * Subscribe listener to topic
 *
 * @method Streaming~Topic#subscribe
 * @param {Callback.<Streaming~StreamingMesasge>} listener - Streaming message listener
 * @returns {Streaming~Topic}
 */
Topic.prototype.subscribe = function(listener) {
  this._streaming.subscribe(this.name, listener);
  return this;
};

/**
 * Unsubscribe listener from topic
 *
 * @method Streaming~Topic#unsubscribe
 * @param {Callback.<Streaming~StreamingMesasge>} listener - Streaming message listener
 * @returns {Streaming~Topic}
 */
Topic.prototype.unsubscribe = function(listener) {
  this._streaming.unsubscribe(this.name, listener);
  return this;
};

/*--------------------------------------------*/

/**
 * Streaming API class
 *
 * @class
 * @extends events.EventEmitter
 * @param {Connection} conn - Connection object
 */
var Streaming = function(conn) {
  this._conn = conn;
};

util.inherits(Streaming, events.EventEmitter);

/** @private **/
Streaming.prototype._createClient = function() {
  var endpointUrl = [ this._conn.instanceUrl, "cometd", this._conn.version ].join('/');
  var fayeClient = new Faye.Client(endpointUrl, {});
  fayeClient.setHeader('Authorization', 'OAuth '+this._conn.accessToken);
  return fayeClient;
};

/**
 * Get named topic
 *
 * @param {String} name - Topic name
 * @returns {Streaming~Topic}
 */
Streaming.prototype.topic = function(name) {
  this._topics = this._topics || {};
  var topic = this._topics[name] = 
    this._topics[name] || new Topic(this, name);
  return topic;
};

/**
 * Subscribe topic
 *
 * @param {String} name - Topic name
 * @param {Callback.<Streaming~StreamingMessage>} listener - Streaming message listener
 * @returns {Streaming}
 */
Streaming.prototype.subscribe = function(name, listener) {
  if (!this._fayeClient) {
    if (Faye.Transport.NodeHttp) {
      Faye.Transport.NodeHttp.prototype.batching = false; // prevent streaming API server error
    }
    this._fayeClient = this._createClient();
  }
  this._fayeClient.subscribe("/topic/"+name, listener);
  return this;
};

/**
 * Unsubscribe topic
 *
 * @param {String} name - Topic name
 * @param {Callback.<Streaming~StreamingMessage>} listener - Streaming message listener
 * @returns {Streaming}
 */
Streaming.prototype.unsubscribe = function(name, listener) {
  if (this._fayeClient) {
    this._fayeClient.unsubscribe("/topic/"+name, listener);
  }
  return this;
};

module.exports = Streaming;