Handle Ajax Request timeouts issue #78

CONTRIBUTORS

@@ -30,3 +30,4 @@ Sanborn Hilland <[email protected]>
 Timothy Drews <[email protected]>
 Vasanth Polipelli <[email protected]>
 Vignesh Venkatasubramanian <[email protected]>
+Roi Lipman <[email protected]>

lib/util/ajax_request.js

@@ -196,6 +196,7 @@ shaka.util.AjaxRequest.prototype.cleanupRequest_ = function() {
     this.xhr_.onload = null;
     this.xhr_.onreadystatechange = null;
     this.xhr_.onerror = null;
+    this.xhr_.ontimeout = null;
   }
   this.xhr_ = null;
 };
@@ -254,6 +255,7 @@ shaka.util.AjaxRequest.prototype.sendInternal = function() {
     this.xhr_.onreadystatechange = this.onReadyStateChange_.bind(this);
   }
   this.xhr_.onerror = this.onError_.bind(this);
+  this.xhr_.ontimeout = this.onTimeout_.bind(this);
 
   for (var k in this.parameters.requestHeaders) {
     this.xhr_.setRequestHeader(k, this.parameters.requestHeaders[k]);
@@ -480,3 +482,34 @@ shaka.util.AjaxRequest.prototype.onError_ = function(event) {
   this.destroy_();
 };
 
+/**
+ * Handles a "timeout" event.
+ *
+ * @param {!ProgressEvent} event The ProgressEvent from this.xhr_.
+ *
+ * @private
+ */
+shaka.util.AjaxRequest.prototype.onTimeout_ = function(event) {
+  if (this.attempts_ < this.parameters.maxAttempts) {
+      this.cleanupRequest_();
+
+    var sendAgain = this.sendInternal.bind(this);
+
+    // Fuzz the delay to avoid tons of clients hitting the server at once
+    // after it recovers from whatever is causing it to fail.
+    var negToPosOne = (Math.random() * 2.0) - 1.0;
+    var negToPosFuzzFactor = negToPosOne * this.parameters.retryFuzzFactor;
+    var fuzzedDelay = this.retryDelayMs_ * (1.0 + negToPosFuzzFactor);
+    window.setTimeout(sendAgain, fuzzedDelay);
+
+    // Store the fuzzed delay to make testing retries feasible.
+    this.lastDelayMs_ = fuzzedDelay;
+
+    // Back off the next delay.
+    this.retryDelayMs_ *= this.parameters.retryBackoffFactor;
+  } else {
+    var error = this.createError_('Request timmedout.', 'net');
+    this.promise_.reject(error);
+    this.destroy_();
+  }
+}