Add test coverage and fix for "Stream XXX is sending an event before being opened" during multi-part file uploads. fixes #948

AFNetworking/AFHTTPClient.m

@@ -1067,11 +1067,22 @@ static const NSUInteger AFMultipartBodyStreamProviderDefaultBufferLength = 4096;
 
 #pragma mark - NSStreamDelegate
 
-- (void)stream:(NSStream __unused *)stream
-   handleEvent:(NSStreamEvent)eventCode
-{
+/**
+ This retry works around a nasty problem in which mutli-part uploads will fail due to the stream delegate being sent a `NSStreamEventHasSpaceAvailable` event before the input stream has finished opening. This workaround simply replays the event after allowing the run-loop to cycle, providing enough time for the input stream to finish opening. It appears that this bug is in the CFNetwork layer. (See https://github.com/AFNetworking/AFNetworking/issues/948)
+ */
+- (void)retryWrite:(NSStream *)stream {
+    [self stream:stream handleEvent:NSStreamEventHasSpaceAvailable];
+}
+
+- (void)stream:(NSStream *)stream
+   handleEvent:(NSStreamEvent)eventCode {
     if (eventCode & NSStreamEventHasSpaceAvailable) {
-        [self handleOutputStreamSpaceAvailable];
+        if (self.inputStream.streamStatus < NSStreamStatusOpen) {
+            // See comments in `retryWrite:` for details
+            [self performSelector:@selector(retryWrite:) withObject:stream afterDelay:0.1];
+        } else {
+            [self handleOutputStreamSpaceAvailable];
+        }
     }
 }
 

Tests/AFHTTPClientTests.m

@@ -199,4 +199,16 @@
     expect(responseDictionary[@"form"]).to.equal(@{ @"key": @"value" });
 }
 
+- (void)testMultipartUploadDoesNotFailDueToStreamSentAnEventBeforeBeingOpenedError {
+    NSString *pathToImage = [[NSBundle bundleForClass:[AFHTTPClient class]] pathForResource:@"abide" ofType:@"jpg"];
+    NSData *imageData = [NSData dataWithContentsOfFile:pathToImage];
+    NSMutableURLRequest *request = [self.client multipartFormRequestWithMethod:@"POST" path:@"/post" parameters:@{ @"this": @"that" } constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
+        [formData appendPartWithFileData:imageData name:@"item[photos_attributes][][photo]" fileName:@"item-image.png" mimeType:@"image/jpg"];
+    }];
+    AFHTTPRequestOperation *operation = [self.client HTTPRequestOperationWithRequest:request success:nil failure:nil];
+    [self.client enqueueHTTPRequestOperation:operation];
+    expect(operation.isFinished).will.beTruthy();
+    expect(operation.error).notTo.equal(NSURLErrorTimedOut);
+}
+
 @end