Send NSDictionary as JSON via POST using NSURLSession

postJson.m

// 1. Populate an NSDictionary with the data you want to send
NSDictionary *exampleData = @{
  @"first": @"Javier",
  @"last": @"Rosas",
  @"address": @"742 Evergreen Terrace"
};

// 2. Serialize your data to JSON format and store it in an NSData object
NSErrpr *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:exampleData options:0 error:&error];

// 3. Set up the request
NSURL *myUrl = [NSURL URLWithString:@"https://mysite.com/v1/users"];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:myUrl];

// 4. Assign our data to the body of the request and set required headers
[request setHTTPBody:jsonData];
[request setHTTPMethod:@"POST"];
[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];

// 5. Initialize our NSURLSession object
NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];

// 6. Get the task and set what will happen at completion
NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
    if (error) {
      // 8. Handle the error
    }
    // 9. Do something with the response object
  }];
  
// 7. Execute request asynchronously
[task resume];