AFNetworking Post Request

It’s first worth adding (as this answer is still popular 6 years after I initially wrote it…) that the first thing you should consider is whether you should even use AFNetworking. NSURLSession was added in iOS 7 and means you don’t need to use AFNetworking in many cases – and one less third party library is always a good thing.

For AFNetworking 3.0:

AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
NSDictionary *params = @{@"user[height]": height,
                         @"user[weight]": weight};
[manager POST:@"https://example.com/myobject" parameters:params progress:nil success:^(NSURLSessionTask *task, id responseObject) {
    NSLog(@"JSON: %@", responseObject);
} failure:^(NSURLSessionTask *operation, NSError *error) {
    NSLog(@"Error: %@", error);
}];

For AFNetworking 2.0 (and also using the new NSDictionary syntax):

AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
NSDictionary *params = @{@"user[height]": height,
                         @"user[weight]": weight};
[manager POST:@"https://example.com/myobject" parameters:params success:^(AFHTTPRequestOperation *operation, id responseObject) {
    NSLog(@"JSON: %@", responseObject);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    NSLog(@"Error: %@", error);
}];

If you are stuck using AFNetworking 1.0, you need to do it this way:

NSURL *url = [NSURL URLWithString:@"https://example.com/"];
AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:url];

NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys:
                        height, @"user[height]",
                        weight, @"user[weight]",
                        nil];
[httpClient postPath:@"/myobject" parameters:params success:^(AFHTTPRequestOperation *operation, id responseObject) {
    NSString *responseStr = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];
    NSLog(@"Request Successful, response '%@'", responseStr);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    NSLog(@"[HTTPClient Error]: %@", error.localizedDescription);
}];