Using AFNetworking for asynchronous POST json requests

Question

I've been trying to use POST json using AFNetworking. After some research I finally got this to work

- (IBAction)go:(id)sender {
    //Some POST
    AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:@"https://www.test.com/"]];
    [httpClient setParameterEncoding:AFJSONParameterEncoding];
    NSMutableURLRequest *request = [httpClient requestWithMethod:@"POST"
                                                            path:@"https://www.test.com/user/login/"
                                                      parameters:@{@"username":self.username.text, @"password":self.password.text}];
    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    [httpClient registerHTTPOperationClass:[AFHTTPRequestOperation class]];
    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        // Print the response body in text
        NSDictionary *jsonDict = (NSDictionary *) responseObject;
        BOOL *success = [[jsonDict objectForKey:@"success"] boolValue];
        NSLog(@"Response: %@", [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding]);
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);
    }];
    [operation start];
}

This is fine for demonstation purposes, but now I want to finally use NSDirectory to split out my json objects, so I tried doing something like this, but my app crashes whenever I enter click on the button

- (IBAction)go:(id)sender {
    //Some POST
    AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:@"https://www.test.com/"]];
    [httpClient setParameterEncoding:AFJSONParameterEncoding];
    NSMutableURLRequest *request = [httpClient requestWithMethod:@"POST"
                                                            path:@"https://www.test.com/user/login/"
                                                      parameters:@{@"username":self.username.text, @"password":self.password.text}];
    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    [httpClient registerHTTPOperationClass:[AFHTTPRequestOperation class]];
    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        // Print the response body in text
        NSDictionary *jsonDict = (NSDictionary *) responseObject;
        BOOL success = [[jsonDict objectForKey:@"success"] boolValue];
        if (success) {
            NSLog(@"yes!!!");
        }else{
            NSString *reason = [jsonDict objectForKey:@"reason"];
            NSLog(@"reason: %@",reason);
        }
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);
    }];
    [operation start];
}

error

2013-03-08 03:27:34.648 test[18253:c07] -[__NSCFData objectForKey:]: unrecognized selector sent to instance 0x888a6b0
2013-03-08 03:27:34.648 test[18253:c07] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFData objectForKey:]: unrecognized selector sent to instance 0x888a6b0'
*** First throw call stack:
(0x1ce0012 0x111de7e 0x1d6b4bd 0x1ccfbbc 0x1ccf94e 0x24608 0x12e71 0x4a4453f 0x4a56014 0x4a467d5 0x1c86af5 0x1c85f44 0x1c85e1b 0x1c3a7e3 0x1c3a668 0x61ffc 0x21ad 0x20d5)
libc++abi.dylib: terminate called throwing an exception

Solution

You are using AFHTTPRequestOperation and not AFJSONRequestOperation.

Also you can use the AFHttpClient directly:

NSDictionary *parameter = @{@"username":self.username.text, @"password":self.password.text};
[httpClient setParameterEncoding:AFJSONParameterEncoding];
[httpClient registerHTTPOperationClass:[AFJSONRequestOperation class]];

[httpClient postPath:@"api/v1/user/login/" parameters:parameter success:^(AFHTTPRequestOperation *operation, id responseObject) {
    // Print the response body in text
    BOOL *success = [[responseObject objectForKey:@"success"] boolValue];
    NSLog(@"Response: %@",responseObject);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    [self handleConnectionError:error];
}];

I would also suggest creating a creating only one instance of the AFHTTPClient using clientWithBaseURL: method.

Comments

[Jonathan]

rckoenes, thats because that is the only post example I could find. can you please elaborate it for me if you dont mind? what changes should be made to the existing code?

[rckoenes]

Also read the documentation on github.com/AFNetworking/AFNetworking it does explain how to correctly use the AFHTTPClient. Have a look at the AFAppDotNetAPIClient this will give you a good example on how to use the AFHTTPClient.

[Jonathan]

Thank you so much rckoenes. but what is handleConnectionError? also, do I not need [operation start]; anymore? and is this method asynchronous as well?

[rckoenes]

The handleConnectionError: is a method that I made my self, such a methods will handle the NSError and present the user with a message. Yes the methods is asynchronous.

[Jonathan]

okay, that makes sense. But I just tested this code. it gives me the same error as my code from above

[rckoenes]

Are you sure that you [httpClient registerHTTPOperationClass:[AFJSONRequestOperation class]]; add this line. This tells AFHTTPClient to use JSON. And add this as well: [httpClient setDefaultHeader:@"Accept" value:@"application/json"]; By the way this is all in the AFNetworking example apps.

[rckoenes]

If you are still using your old code dit you also replace the AFHTTPRequestOperation *operation with AFJSONRequestOperation *operation

[Sheharyar]

I'm literally crying. Thankyou. Thankyou!

[Ben]

Please edit your answer, and explain how this solves the problem.