Simple http post example in Objective-C?

Question

I have a php webpage that requires a login (userid & password). I have the user enter the information into the app just fine.. but I need an example on how to do a POST

Answer 1

I am a beginner in iPhone apps and I still have an issue although I followed the above advices. It looks like POST variables are not received by my server - not sure if it comes from php or objective-c code ...

the objective-c part (coded following Chris' protocol methodo)

// Create the request.
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://example.php"]];

// Specify that it will be a POST request
request.HTTPMethod = @"POST";

// This is how we set header fields
[request setValue:@"application/xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"];

// Convert your data and set your request's HTTPBody property
NSString *stringData = [NSString stringWithFormat:@"user_name=%@&password=%@", self.userNameField.text , self.passwordTextField.text];
NSData *requestBodyData = [stringData dataUsingEncoding:NSUTF8StringEncoding];
request.HTTPBody = requestBodyData;

// Create url connection and fire request
//NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
NSData *response = [NSURLConnection sendSynchronousRequest:request
                                         returningResponse:nil error:nil];

NSLog(@"Response: %@",[[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding]);

Below the php part :

if (isset($_POST['user_name'],$_POST['password'])) 

{

// Create connection
$con2=mysqli_connect($servername, $username, $password, $dbname);
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
else 
{
// retrieve POST vars
$username = $_POST['user_name'];
$password = $_POST['password'];

$sql = "INSERT INTO myTable (user_name, password) VALUES ('$username',   '$password')";
$retval = mysqli_query( $sql, $con2 );
if(! $retval )
{
die('Could not enter data: ' . mysql_error());
}
echo "Entered data successfully\n";

mysqli_close($con2);

}
}
else
{
echo "No data input in php";
}

I have been stuck the last days on this one.

Answer 2

This is what I recently used, and it worked fine for me:

NSString *post = @"key1=val1&key2=val2";
NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];

NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]];

NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
[request setURL:[NSURL URLWithString:@"http://www.nowhere.com/sendFormHere.php"]];
[request setHTTPMethod:@"POST"];
[request setValue:postLength forHTTPHeaderField:@"Content-Length"];
[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
[request setHTTPBody:postData];

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Originally taken from http://deusty.blogspot.com/2006/11/sending-http-get-and-post-from-cocoa.html, but that blog does not seem to exist anymore.