AFNetworking 2.0 - how to pass response to another class on success from subclassed AFHTTPSessionManager

Question

Beginner ios AFNetworking 2.0 Qns: Having subclassed AFHTTPSessionManager to something like "MyAPIManager" and placed my all my API calls (GET/POST/PUT etc.) in this custom manager class, I'm having problems making use of the response on request success in another class (say class B).

I know I can refactor this and pluck out the POST call portion to class B, so that I can dump the relevant class B methods in the callback, but this would get messy, especially with multiple API calls.

I want to pass this response (e.g. the returned objectId) to another class and right now I'm just using a NSNotification which class B listens for, but this still feels a bit 'hackish' and am wondering if there is a better way to do this.

Currently in MyAPIManager : AFHTTPSessionManager:

- (void) POSTRecordJson:(NSDictionary *)json
{
[self POST:@"classes/Record/" parameters:json success:^(NSURLSessionDataTask *task, id responseObject) {
    NSLog(@"Posted JSON: %@", json.description);
    if ([responseObject isKindOfClass:[NSDictionary class]]) {
        NSLog(@"Response: %@", responseObject);
        //Notify objectId received
        [[NSNotificationCenter defaultCenter]
         postNotificationName:@"ReceivedObjectIdNotification"
         object:self
         userInfo:responseObject];
    }
} failure:^(NSURLSessionDataTask *task, NSError *error) {
    NSLog(@"Error: %@", error);
}];
}

And in Class B I've called:

MyApiManager *manager = [MyApiManager sharedInstance];
[manager POSTRecordJson:someJSONdict];

Answer 1

you could do 2 things.. by using a protocol/delegate or a block..

but i, personally, prefers block soo..

first make a block Datatype

typedef void(^SuccessBlock)(id success); example

and add the parameter with the block on it

- (void) POSTRecordJson:(NSDictionary *)json success:(SuccessBlock)success
{
[self POST:@"classes/Record/" parameters:json success:^(NSURLSessionDataTask *task, id responseObject) {
    NSLog(@"Posted JSON: %@", json.description);
    if ([responseObject isKindOfClass:[NSDictionary class]]) {
        NSLog(@"Response: %@", responseObject);
        //Notify objectId received
        success(responseObject);

    }
} failure:^(NSURLSessionDataTask *task, NSError *error) {
    NSLog(@"Error: %@", error);
}];
}

and to call the new function..

MyApiManager *manager = [MyApiManager sharedInstance];
[manager POSTRecordJson:someJSONdict success:^(id result){
    NSDictionary *dictionary = (NSDictionary *)result;
    NSLog(@"response: %@",dictionary)
}];

Answer 2

You would want to pass a completion block into your -POSTRecordJson: method.

For example, you would refactor your method to do the following:

- (void) POSTRecordJson:(NSDictionary *)json completion:(void(^)(BOOL success, id response, NSError *error))completion
{
    [self POST:@"classes/Record/" parameters:json success:^(NSURLSessionDataTask *task, id responseObject) {

        NSLog(@"Posted JSON: %@", json.description);
        if ([responseObject isKindOfClass:[NSDictionary class]])
        {
            NSLog(@"Response: %@", responseObject);

            if (completion) //if completion is NULL, calling it will crash your app so we always check that it is present.
            {
                completion(YES, responseObject, nil);
            }
        }
    } failure:^(NSURLSessionDataTask *task, NSError *error) {

        NSLog(@"Error: %@", error);

        if (completion)
        {
            completion(NO, nil, error);
        }

    }];
}

You could then handle this implementation like so:

//assuming `manager` and `dictionary` exist.

[manager POSTRecordJson:dictionary completion^(BOOL success, id response, NSError *error) {

    if (success)
    {
        //do something with `response`
    }
    else
    {
        //do something with `error`
    }

}];

However, if you are a beginner with AFNetworking and you want to adopt a great structure for handling web services, you should check out this excellent blog post.

Answer 3

You can use blocks to send the response back to the class after the response received from the server:

- (void) POSTRecordJson:(NSDictionary *)json response:(void (^)(id response, NSError *error))responseBlock
    {
    [self POST:@"classes/Record/" parameters:json success:^(NSURLSessionDataTask *task, id responseObject) {
        NSLog(@"Posted JSON: %@", json.description);
        if ([responseObject isKindOfClass:[NSDictionary class]]) {
            NSLog(@"Response: %@", responseObject);
           responseBlock(responseObject, nil);
        }
    } failure:^(NSURLSessionDataTask *task, NSError *error) {
        NSLog(@"Error: %@", error);
         responseBlock(nil, error);
    }];
    }