Question

I’ve searched and can’t find this already on here:

I’m trying to send an NSData object to a web service. The NSData object is a JSON object using iOS 5’s built in JSON.

I need to do an async send, and then check the response back from the server.

I do NOT want to use any 3rd party libraries.

Here is what I’ve got already that doesn’t work:

NSDictionary * initialLogAsJSON = [NSDictionary dictionaryWithObjects:items forKeys:keys];

NSError * error;

NSData * jsonData = [NSJSONSerialization dataWithJSONObject:initialLogAsJSON options:NSJSONWritingPrettyPrinted error:&error];

NSMutableURLRequest * request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:kURLSendTestStartedDataToTenOneServer ]];

[request setHTTPMethod:@"POST"];
[request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
[request setValue:@"appliction/json" forHTTPHeaderField:@"Content-Type"];
[request setValue:[NSString stringWithFormat:@"%d", [jsonData length]] forHTTPHeaderField:@"Content-Length"];
[request setHTTPBody: jsonData];

[NSURLConnection sendAsynchronousRequest:request
                                   queue:self.queue
                       completionHandler:^( NSURLResponse * response, NSData * data, NSError * error )
                                        {
                                            NSLog( @"If finished with reponse = %@\nData: %@\nError %@", response, data, error );
                                            // do something useful
                                        }
];

Answer 1

Actually the problem was easier that than..

It was down to the URL being nil – because of some funny escape characters in the source strings.

Here’s my final (working) implementation:

NSDictionary * mainJSON = [NSDictionary dictionaryWithObjects:mainItems forKeys:mainKeys];

NSError * error;

NSData * jsonData = [NSJSONSerialization dataWithJSONObject:mainJSON options:NSJSONWritingPrettyPrinted error:&error];

NSString * jsonString = [[NSString alloc] initWithData:jsonData encoding:NSASCIIStringEncoding];

NSString * serverString = [NSString stringWithFormat:@"%@", kURLServer];

NSString * urlString = [NSString stringWithFormat:@"%@%@", serverString, jsonString];

NSString * webStringURL = [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

NSURL * url = [NSURL URLWithString:webStringURL];

NSAssert( url != nil, @"URL nil - Check string values for URL to Server!" );

dispatch_async( kBackgroundQueue, ^
                                   {
                                       NSData * data = [NSData dataWithContentsOfURL:url];
                                                   [self performSelectorOnMainThread:@selector( receivedResponseFromServer: )
                                                                          withObject:data
                                                                       waitUntilDone:YES];
                                   }
               );