Question

I would like to ask about the button and the url post method in iPhone application.

In my program, I want the user to click a button, and then a url will be called by POST method. For the url, it may need to redirect to somewhere (302 or 303) etc and final is 200.

I have complete the button and the success page, however, I don’t know how to use the objective-C library. I found lots of reference of this forum, but I don’t understand what the code means. Can anyone help me?

The following is a question which I believe related to the question.
Invoking a http post URL from iphone using .net web service

Thank you very much.

Answer 1

If you’re okay with blocking the thread you’re making the request on, this is just about as simple as it gets.

NSString *postBody = [NSString stringWithFormat:@"param1=%@&param2", param1value, param2value];
NSData *postData = [postBody dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:targetURL];
[request setHTTPMethod:@"POST"];
[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
[request setValue:postLength forHTTPHeaderField:@"Content-Length"];
[request setHTTPBody:postData];

NSURLResponse *response = nil;
NSError *error = nil;
NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

A few caveats:

• This will perform a synchronous (blocking) request, so either do it on a background thread or look into using the NSURLConnection delegate methods.
• POST data must be URL-encoded, so you may need to do some preprocessing of your parameter values.
• Redirects will occur automatically until a 200 OK or an error is encountered.