Can I make POST or GET requests from an iphone application?

Question

Assume your class has a responseData instance variable, then:

responseData = [[NSMutableData data] retain];

NSURLRequest *request =
    [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.domain.com/path"]];
[[NSURLConnection alloc] initWithRequest:request delegate:self];

And then add the following methods to your class:

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    [responseData setLength:0];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    [responseData appendData:data];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    // Show error
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    // Once this method is invoked, "responseData" contains the complete result
}

This will send a GET. By the time the final method is called, responseData will contain the entire HTTP response (convert to string with [[NSString alloc] initWithData:encoding:].

Alternately, for POST, replace the first block of code with:

NSMutableURLRequest *request =
        [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://www.domain.com/path"]];
[request setHTTPMethod:@"POST"];

NSString *postString = @"Some post string";
[request setHTTPBody:[postString dataUsingEncoding:NSUTF8StringEncoding]];

If you're using Objective C, you'll need to use the NSURL, NSURLRequest, and NURLConnection classes. Apple's NSURLRequest doc. HttpRequest is for JavaScript.