iOS 5 Programming Cookbook

8.6. Sending HTTP POST Requests with NSURLConnection

Problem

You want to call a web service using 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

I have set up a dummy web service at the following address: http://pixolity.com/post.php. If you open this URL in your browser, you will see something similar to the screen shown in Figure 8-3.

Figure 8-3. The POST web service opened in a web browser

This web service expects POST requests and is able to print out parameters that are sent as part of the query string and as part of the HTTP body. You can send both, if you want to. 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 the aforementioned URL:

NSString *urlAsString = @"http://pixolity.com/post.php"; 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"; ...