Migrating from NSURLConnection to NSURLSession - ios

Question

I am trying to migrate to NSURLSession so I can send multiple images to my server and stop when I get the needed response. But my completion block never gets called. Would appreciate if you could tell me if I am doing the migration correctly.
Here is my old code that works fine-
-(void) sendImgWithText:(UIImage*)img
{
NSURL *requestURL = [NSURL URLWithString:#"Some URL"];
// create request
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
[request setCachePolicy:NSURLRequestReloadIgnoringLocalCacheData];
[request setHTTPShouldHandleCookies:NO];
[request setTimeoutInterval:30];
[request setHTTPMethod:#"POST"];
NSString *boundary = #"*****";
NSString *lineEnd = #"\r\n";
NSString *twoHyphens = #"--";
// set Content-Type in HTTP header
NSString *contentType = [NSString stringWithFormat:#"multipart/form-data; boundary=%#", boundary];
[request setValue:contentType forHTTPHeaderField: #"Content-Type"];
// post body
NSMutableData *body = [NSMutableData data];
// add params (all params are strings)
// UIImage *imgColor = [UIImage imageNamed:#"9.jpg"];
UIImage * imageToPost = [[UIImage alloc] init];
UIImageWriteToSavedPhotosAlbum(imageToPost, nil, nil, nil);
NSData *imageData = UIImageJPEGRepresentation(imageToPost, 1.0);
if (imageData) {
[body appendData:[[NSString stringWithFormat:#"%#%#%#", twoHyphens,boundary, lineEnd] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:#"Content-Disposition: form-data; name=\"uploadedfile\"; filename=\"test.jpg\"%#",lineEnd] dataUsingEncoding:NSUTF8StringEncoding]];
// [body appendData:[#"Content-Type: image/jpeg\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:#"%#",lineEnd] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:imageData];
[body appendData:[[NSString stringWithFormat:#"%#",lineEnd] dataUsingEncoding:NSUTF8StringEncoding]];
}
[body appendData:[[NSString stringWithFormat:#"%#%#%#%#", twoHyphens,boundary, twoHyphens,lineEnd] dataUsingEncoding:NSUTF8StringEncoding]];
// setting the body of the post to the reqeust
[request setHTTPBody:body];
// set the content-length
NSString *postLength = [NSString stringWithFormat:#"%d", [body length]];
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
NSLog(#"%#",requestURL);
NSLog(#"%f,%f",imageToPost.size.height,imageToPost.size.height);
// set URL
[request setURL:requestURL];
NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
}
And here is the version(I got most of it from other stack overflow articles)
- (void) serverRequestWithImage:(UIImage *)img completion:(void (^)(id responseObject, NSError *error))completion
{
NSURL *requestURL = [NSURL URLWithString:#"Some URL"];
// create request
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
[request setCachePolicy:NSURLRequestReloadIgnoringLocalCacheData];
[request setHTTPShouldHandleCookies:NO];
[request setTimeoutInterval:30];
[request setHTTPMethod:#"POST"];
NSString *boundary = #"*****";
NSString *lineEnd = #"\r\n";
NSString *twoHyphens = #"--";
// set Content-Type in HTTP header
NSString *contentType = [NSString stringWithFormat:#"multipart/form-data; boundary=%#", boundary];
[request setValue:contentType forHTTPHeaderField: #"Content-Type"];
// post body
NSMutableData *body = [NSMutableData data];
UIImage * imageToPost = [[UIImage alloc] init];
imageToPost = img;
NSData *imageData = UIImageJPEGRepresentation(imageToPost, 1.0);
if (imageData) {
[body appendData:[[NSString stringWithFormat:#"%#%#%#", twoHyphens,boundary, lineEnd] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:#"Content-Disposition: form-data; name=\"uploadedfile\"; filename=\"test.jpg\"%#",lineEnd] dataUsingEncoding:NSUTF8StringEncoding]];
// [body appendData:[#"Content-Type: image/jpeg\r\n\r\n" dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:[[NSString stringWithFormat:#"%#",lineEnd] dataUsingEncoding:NSUTF8StringEncoding]];
[body appendData:imageData];
[body appendData:[[NSString stringWithFormat:#"%#",lineEnd] dataUsingEncoding:NSUTF8StringEncoding]];
}
[body appendData:[[NSString stringWithFormat:#"%#%#%#%#", twoHyphens,boundary, twoHyphens,lineEnd] dataUsingEncoding:NSUTF8StringEncoding]];
// setting the body of the post to the reqeust
[request setHTTPBody:body];
// set the content-length
NSString *postLength = [NSString stringWithFormat:#"%d", [body length]];
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
NSLog(#"%#",requestURL);
NSLog(#"%f,%f",imageToPost.size.height,imageToPost.size.height);
// set URL
[request setURL:requestURL];
NSURLSessionTask *task =
[session
dataTaskWithRequest:request
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error)
{
// report any network-related errors
NSLog(#"Got Response 1");
if (!data) {
if (completion) {
dispatch_async(dispatch_get_main_queue(), ^{
completion(nil, error);
});
}
return;
}
// report any errors parsing the JSON
NSError *parseError = nil;
_responseData = [NSMutableData dataWithData:data];
if (_responseData) {
if (completion) {
dispatch_async(dispatch_get_main_queue(), ^{
completion(nil, parseError);
});
}
return;
}
// if everything is ok, then just return the JSON object
if (completion) {
dispatch_async(dispatch_get_main_queue(), ^{
completion(_returnedData, nil);
});
}
}];
[task resume];
}
And here is my call method from the other class
- (IBAction)GetData:(id)sender
{
[_imageView setImage:[UIImage imageNamed:#"9.jpg"]];
msg = [[Message alloc] init];
[msg initData];
msg.delegate=self;
[msg serverRequestWithImage:_imageView.image completion:^(id responseObject, NSError *error)
{
if (responseObject) {
// do what you want with the response object here
NSLog(#"Got Data");
} else {
NSLog(#"%s: serverRequest error: %#", __FUNCTION__, error);
}
}];
}

Answer 1

Items:
I didn't see the initialization of NSURLSession. That's something you should show in your question. You could also check in your "send image" method that session is non-nil.
It looks like you are starting with a file (#"9.jpg"). If so, -[NSURLSession uploadTaskWithRequest:fromFile:completionHandler:] might save you a bunch of trouble.
Unrequested advice, with all that entails: :)
In my view, -serverRequestWithImage:completion: is a poor name for that method. It implies that it returns a request object, and does not tell you that it actually sends the request. Something active, like -uploadImage:completionHandler: might be better.
Idiomatically, all method names should start lowercase, i.e. -getData:.