Add oauth timestamp fixing (using twitter server offset) to streaming…

… api client

.gitignore

@@ -1,3 +1,4 @@
 node_modules
 config*.js
-test.js
+test.js
+.DS_Store

lib/streaming-api-connection.js

@@ -12,6 +12,7 @@ var STATUS_CODES_TO_ABORT_ON = require('./settings').STATUS_CODES_TO_ABORT_ON
 var StreamingAPIConnection = function (reqOpts, twitOptions) {
   this.reqOpts = reqOpts
   this.twitOptions = twitOptions
+  this._twitter_time_minus_local_time_ms = 0
   EventEmitter.call(this)
 }
 
@@ -64,9 +65,11 @@ StreamingAPIConnection.prototype._startPersistentConnection = function () {
   self._resetConnection();
   self._setupParser();
   self._resetStallAbortTimeout();
+  self._setOauthTimestamp();
   self.request = request.post(this.reqOpts);
   self.emit('connect', self.request);
   self.request.on('response', function (response) {
+    self._updateOauthTimestampOffsetFromResponse(response)
     // reset our reconnection attempt flag so next attempt goes through with 0 delay
     // if we get a transport-level error
     self._usedFirstReconnect = false;
@@ -322,4 +325,34 @@ StreamingAPIConnection.prototype._handleDisconnect = function (twitterMsg) {
   this.stop();
 }
 
+/**
+ * Call whenever an http request is about to be made to update
+ * our local timestamp (used for Oauth) to be Twitter's server time.
+ *
+ */
+StreamingAPIConnection.prototype._setOauthTimestamp = function () {
+  var self = this;
+  if (self.reqOpts.oauth) {
+    var oauth_ts = Date.now() + self._twitter_time_minus_local_time_ms;
+    self.reqOpts.oauth.timestamp = Math.floor(oauth_ts/1000).toString();
+  }
+}
+
+/**
+ * Call whenever an http response is received from Twitter,
+ * to set our local timestamp offset from Twitter's server time.
+ * This is used to set the Oauth timestamp for our next http request
+ * to Twitter (by calling _setOauthTimestamp).
+ *
+ * @param  {http.IncomingResponse} resp   http response received from Twitter.
+ */
+StreamingAPIConnection.prototype._updateOauthTimestampOffsetFromResponse = function (resp) {
+  if (resp && resp.headers && resp.headers.date &&
+      new Date(resp.headers.date).toString() !== 'Invalid Date'
+  ) {
+    var twitterTimeMs = new Date(resp.headers.date).getTime()
+    this._twitter_time_minus_local_time_ms = twitterTimeMs - Date.now();
+  }
+}
+
 module.exports = StreamingAPIConnection