iOS 7 Programming Cookbook

11.6. Sending HTTP POST Requests with NSURLConnection

Problem

You want to call a web service using the HTTP POST method, and perhaps pass parameters (as part of the HTTP body or in the query string) to the web service.

Solution

Just as with the GET method, we can use the POST method using NSURLConnection. We must explicitly set our URL’s method to POST.

Discussion

Let’s write a simple app that can create an asynchronous connection and send a few parameters as a query string and a few parameters in the HTTP body to a URL:

- (BOOL)            application:(UIApplication *)application
  didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{

    NSString *urlAsString = <# Place the URL of the web server here #>;
    urlAsString = [urlAsString stringByAppendingString:@"?param1=First"];
    urlAsString = [urlAsString stringByAppendingString:@"&param2=Second"];

    NSURL *url = [NSURL URLWithString:urlAsString];

    NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:url];
    [urlRequest setTimeoutInterval:30.0f];
    [urlRequest setHTTPMethod:@"POST"];

    NSString *body = @"bodyParam1=BodyValue1&bodyParam2=BodyValue2";
    [urlRequest setHTTPBody:[body dataUsingEncoding:NSUTF8StringEncoding]];

    NSOperationQueue *queue = [[NSOperationQueue alloc] init];

    [NSURLConnection
     sendAsynchronousRequest:urlRequest
     queue:queue
     completionHandler:^(NSURLResponse *response,
                         NSData *data,
                         NSError *error) {

         if ([data length] >0  && error == nil){
             NSString *html =
             [[NSString alloc] initWithData:data
                                   encoding:NSUTF8StringEncoding];