Invoking a http post URL from iphone using .net web service

I need to call a url from my iphone when i tap on a button.

The url is taking a value from the UITextField as argument, also it is using a POST method to invoke the webservice. how do i use the URL in my iphone. I had done the same with GET method. but for that i created a url string with the value from the textfield. it cant be use for the POST one. so what shoud i do for that. is there any sample code for this.. Also the web service is a ".asmx" type. This is what i had done.....

-(IBAction)loginButtonPressed:(id)sender{
NSString *post =[NSString stringWithFormat:@"name=myUserName&pass=myPassword"];
NSLog(post);        

NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];

NSString *postLength = [NSString stringWithF开发者_运维百科ormat:@"%d", [postData length]];

NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];

[request setURL:[NSURL URLWithString:@"http://192.168.50.194:9989/webservice1.asmx?op=LoginAuthentication"]];
[request setHTTPMethod:@"POST"];
[request setValue:postLength forHTTPHeaderField:@"Content-Length"];
[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
[request setHTTPBody:postData];


NSError *error;
NSURLResponse *response;
NSData *urlData=[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
NSString *data=[[NSString alloc]initWithData:urlData encoding:NSUTF8StringEncoding];
NSLog(data);

}

The error i am getting is

<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><soap:Body><soap:Fault><soap:Code><soap:Value>soap:Receiver</soap:Value></soap:Code><soap:Reason><soap:Text xml:lang="en">Server was unable to process request. ---&gt; Data at the root level is invalid. Line 1, position 1.</soap:Text></soap:Reason><soap:Detail /></soap:Fault></soap:Body></soap:Envelope>

Please Help me.!!!

Thanks, Shibin

i got it working thanks for your support.. here is the working code...

-(IBAction)loginButtonPressed:(id)sender{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSLog(loginID.text);
NSLog(loginPassword.text);
NSString *soapMsg = [[NSString alloc] initWithFormat:@"<?xml version=\"1.0\" encoding=\"utf-8\"?><soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\"><soap:Body><IphoneAuthenticateduser xmlns=\"http://tempuri.org/\"><UserName>%@</UserName><Passwordtext>%@</Passwordtext></IphoneAuthenticateduser></soap:Body></soap:Envelope>",loginID.text,loginPassword.text];
NSLog(soapMsg);
NSURL *url = [NSURL URLWithString:@"http://192.168.50.194:9989/Iphoneauthentication.asmx"];
NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url];
NSString *msgLength = [NSString stringWithFormat:@"%d", [soapMsg length]];

[req addValue:@"text/xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"];
[req addValue:@"http://tempuri.org/IphoneAuthenticateduser" forHTTPHeaderField:@"SOAPAction"];
[req addValue:msgLength forHTTPHeaderField:@"Content-Length"];
[req setHTTPMethod:@"POST"];
[req setHTTPBody: [soapMsg dataUsingEncoding:NSUTF8StringEncoding]];

NSError *error;
NSURLResponse *response;
NSData *urlData=[NSURLConnection sendSynchronousRequest:req returningResponse:&response error:&error];

if(!response){
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Connection Error"
                                                    message:@"Failed to Connect to the Internet"
                                                   delegate:self
                                          cancelButtonTitle:@"OK"
                                          otherButtonTitles:nil];
    [alert show];
    [alert release];
}
else{
    xmlResult=[[NSString alloc]initWithData:urlData encoding:NSUTF8StringEncoding];

    NSXMLParser *xmlParser = [[NSXMLParser alloc] initWithData:urlData];
    XMLParser *parser = [[XMLParser alloc] initXMLParser];
    [xmlParser setDelegate:parser];
    sucess = [xmlParser parse];

    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;

    if(sucess){
        NSLog(appDelegate.message);
        if(appDelegate.message != NULL){
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Login Failed"
                                                            message:appDelegate.message
                                                           delegate:self
                                                  cancelButtonTitle:@"OK"
                                                  otherButtonTitles:nil];
            [alert show];
            [alert release];
            appDelegate.message = NULL;
        }
        else{
            UserViewController *userController = [[UserViewController alloc] initWithNibName:@"UserViewController"
                                                                                  bundle:nil];
            [self presentModalViewController:userController animated:YES];
            [userController release];
        }
    }
    else{
        NSLog(@"Parsing Failed");
    }
}
[pool release];

}

You can set the HTTP method to use POST instead of the default GET using something like this:

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:myURL];
[request setHTTPMethod:@"POST"];