Objective c 向服务器发送文件并接收反馈

我有以下代码，用于向我的服务器发送文件：

  NSData *data = [NSData dataWithContentsOfFile:path];
    NSMutableString *urlString = [[NSMutableString alloc] initWithFormat:@"name=thefile&&filename=recording"];
    [urlString appendFormat:@"%@", data];
    NSData *postData = [urlString dataUsingEncoding:NSASCIIStringEncoding
                               allowLossyConversion:YES];
    NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]];
    NSString *baseurl = @"http://websitetester.com/here.php";

    NSURL *url = [NSURL URLWithString:baseurl];
    NSMutableURLRequest *urlRequest = [NSMutableURLRequest requestWithURL:url];
    [urlRequest setHTTPMethod: @"POST"];
    [urlRequest setValue:postLength forHTTPHeaderField:@"Content-Length"];
    [urlRequest setValue:@"application/x-www-form-urlencoded"
      forHTTPHeaderField:@"Content-Type"];
    [urlRequest setHTTPBody:postData];

    NSURLConnection *connection = [NSURLConnection connectionWithRequest:urlRequest delegate:self];
    [connection start];

    NSLog(@"File Send to server!");

这段代码工作得非常完美，但我希望从服务器收到一个返回，在代码末尾显示的php文件：

<?php

if(...){

...

echo "Data Received";

}else{

...

echo "Error in server";
}

?>

嘿，我在Objective-c中找到一个接收返回数据的代码，代码是：

NSURLResponse* response;
    NSError* error;


    NSData* result = [NSURLConnection sendSynchronousRequest:urlRequest returningResponse:&response error:&error];

    NSString *returnString = [[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding];
    NSLog(@"return: %@",returnString);

现在代码按我预期的方式工作

NSURLResponse* response;
    NSError* error;


    NSData* result = [NSURLConnection sendSynchronousRequest:urlRequest returningResponse:&response error:&error];

    NSString *returnString = [[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding];
    NSLog(@"return: %@",returnString);