Use Retry-After if available

Author: benvinegar

src/raven.js

@@ -1326,6 +1326,36 @@ Raven.prototype = {
         return this._backoffDuration && now() - this._backoffStart < this._backoffDuration;
     },
 
+    _setBackoffState: function(request) {
+        // if we are already in a backoff state, don't change anything
+        if (this._shouldBackoff())
+            return;
+
+        var status = request.status;
+
+        // 400 - project_id doesn't exist or some other fatal
+        // 401 - nvalid/revoked dsn
+        // 429 - too many requests
+        if (!(status === 400 || status === 401 || status === 429))
+            return;
+
+        var retry;
+        try {
+            // If Retry-After is not in Access-Control-Allow-Headers, most
+            // browsers will throw an exception trying to access it
+            retry = request.getResponseHeader('Retry-After');
+            retry = parseInt(retry, 10);
+        } catch (e) {
+            /* eslint no-empty:0 */
+        }
+
+        this._backoffDuration = retry
+            ? retry
+            : this._backoffDuration * 2 || 1000;
+
+        this._backoffStart = now();
+    },
+
     _send: function(data) {
         if (this._shouldBackoff()) {
             return;
@@ -1453,10 +1483,8 @@ Raven.prototype = {
                 callback && callback();
             },
             onError: function failure(error) {
-                // too many requests
-                if (!self._shouldBackoff() && error.request && error.request.status === 429) {
-                    self._backoffDuration = self._backoffDuration * 2 || 1000;
-                    self._backoffStart = now();
+                if (error.request) {
+                    self._setBackoffState(error.request);
                 }
 
                 self._triggerEvent('failure', {

test/raven.test.js

@@ -1193,6 +1193,24 @@ describe('globals', function() {
             assert.equal(Raven._backoffDuration, 2000);
         });
 
+
+        it('should set backoffDuration to value of Retry-If header if present', function () {
+            this.sinon.stub(Raven, 'isSetup').returns(true);
+            this.sinon.stub(Raven, '_makeRequest');
+
+            Raven._send({message: 'bar'});
+            var opts = Raven._makeRequest.lastCall.args[0];
+            var mockError = new Error('401: Unauthorized');
+            mockError.request = {
+                status: 401,
+                getResponseHeader: sinon.stub().withArgs('Retry-After').returns('1337')
+            };
+            opts.onError(mockError);
+
+            assert.equal(Raven._backoffStart, 100); // clock is at 100ms
+            assert.equal(Raven._backoffDuration, 1337); // converted to int
+        });
+
         it('should reset backoffDuration and backoffStart if onSuccess is fired (200)', function () {
             this.sinon.stub(Raven, 'isSetup').returns(true);
             this.sinon.stub(Raven, '_makeRequest');