Move all source files into 'src' folder.

src/GCM.js

@@ -0,0 +1,82 @@
+var Parse = require('parse/node').Parse;
+var gcm = require('node-gcm');
+var randomstring = require('randomstring');
+
+var GCMTimeToLiveMax = 4 * 7 * 24 * 60 * 60; // GCM allows a max of 4 weeks
+var GCMRegistrationTokensMax = 1000;
+
+function GCM(apiKey) {
+  this.sender = new gcm.Sender(apiKey);
+}
+
+/**
+ * Send gcm request.
+ * @param {Object} data The data we need to send, the format is the same with api request body
+ * @param {Array} registrationTokens A array of registration tokens
+ * @returns {Object} A promise which is resolved after we get results from gcm
+ */
+GCM.prototype.send = function (data, registrationTokens) {
+  if (registrationTokens.length >= GCMRegistrationTokensMax) {
+    throw new Parse.Error(Parse.Error.PUSH_MISCONFIGURED,
+                          'Too many registration tokens for a GCM request.');
+  }
+  var pushId = randomstring.generate({
+    length: 10,
+    charset: 'alphanumeric'
+  });
+  var timeStamp = Date.now();
+  var expirationTime;
+  // We handle the expiration_time convertion in push.js, so expiration_time is a valid date
+  // in Unix epoch time in milliseconds here
+  if (data['expiration_time']) {
+    expirationTime = data['expiration_time'];
+  }
+  // Generate gcm payload
+  var gcmPayload = generateGCMPayload(data.data, pushId, timeStamp, expirationTime);
+  // Make and send gcm request
+  var message = new gcm.Message(gcmPayload);
+  var promise = new Parse.Promise();
+  this.sender.send(message, { registrationTokens: registrationTokens }, 5, function (error, response) {
+    // TODO: Use the response from gcm to generate and save push report
+    // TODO: If gcm returns some deviceTokens are invalid, set tombstone for the installation
+    promise.resolve();
+  });
+  return promise;
+}
+
+/**
+ * Generate the gcm payload from the data we get from api request.
+ * @param {Object} coreData The data field under api request body
+ * @param {String} pushId A random string
+ * @param {Number} timeStamp A number whose format is the Unix Epoch
+ * @param {Number|undefined} expirationTime A number whose format is the Unix Epoch or undefined
+ * @returns {Object} A promise which is resolved after we get results from gcm
+ */
+var generateGCMPayload = function(coreData, pushId, timeStamp, expirationTime) {
+  var payloadData =  {
+    'time': new Date(timeStamp).toISOString(),
+    'push_id': pushId,
+    'data': JSON.stringify(coreData)
+  }
+  var payload = {
+    priority: 'normal',
+    data: payloadData
+  };
+  if (expirationTime) {
+   // The timeStamp and expiration is in milliseconds but gcm requires second
+    var timeToLive = Math.floor((expirationTime - timeStamp) / 1000);
+    if (timeToLive < 0) {
+      timeToLive = 0;
+    }
+    if (timeToLive >= GCMTimeToLiveMax) {
+      timeToLive = GCMTimeToLiveMax;
+    }
+    payload.timeToLive = timeToLive;
+  }
+  return payload;
+}
+
+if (typeof process !== 'undefined' && process.env.NODE_ENV === 'test') {
+  GCM.generateGCMPayload = generateGCMPayload;
+}
+module.exports = GCM;