Requesting data from Web Server on iPhone creates too much of a delay

In my iPhone app, I need to access the webserver to login into my system. The client requires that the database be on server only. So I have made an admin panel in ASP.NET and MySQL database where in I store the login information.

Now when I use the method given below in the code to fetch the data from server then it takes too much of time (i.e. More than a minute.) to respond.

In the case where I have fetched a particular data from server before, then that value is fetched fast when I try to fetch it the next time. But for new data it again takes lots of time or rather times out.

Sometimes the request even times out.

What should I do to decrease the delay and speed up the whole login process?

Is there a better way to do this?

Info regarding Code below:

firstname.text is my Username.

lastname.text is my Password.

label.text is a temporary label that I use to store the password obtained from server.

allUsers is the array where the response obtained from server is stored.

Also I am using JSON to parse the data between webserver and iPhone.

I use a plist to store my url. Plist name is url.plist.

Code is as Below:

    SBJSON *json = [SBJSON new];
    json.humanReadable = YES;
    NSString *service = @"/getUserInfo";
    //NSString *requestString = [NSString stringWithFormat:@"{\"method\":\"%@\"}",  service];
    NSString *requestString = [NSString stringWithFormat:@"{\"firstname\":\"%@\"}",firstName.text,nil];
    NSLog(@"Request String: %@", requestString);

    NSData *requestData = [NSData dataWithBytes: [requestString UTF8String] length: [requestString length]];

    NSString *fileLoc = [[NSBundle mainBundle] pathForResource:@"url" ofType:@"plist" ];
    NSDictionary *fileContents = [[NSDictionary alloc] initWithContentsOfFile:fileLoc];
    NSString *urlLoc = [fileContents objectForKey:@"baseURL"];
    urlLoc = [urlLoc stringByAppendingString:service];
    NSLog(@"URL is %@",urlLoc);
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL: 
                                    [NSURL URLWithString: urlLoc]];  

    NSString *postLength = [NSString stringWithFormat:@"%d", [requestData length]];
    [request setHTTPMethod: @"POST"];
    [request setValue:postLength forHTTPHeaderField:@"Content-Length"];
    [request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];
    [request setHTTPBody: requestData];

    //Data returned by WebService
    NSError *respError = nil; 
    NSData *returnData = [NSURLConnection sendSynchronousRequest: request returningResponse: nil error: &respError ];

    if (respError) {
        NSString *msg = [NSString stringWithFormat:@"Connection failed! Error - %@ %@",
                         [respError localizedDescription],
                         [[respError userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]];   

        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Check your network connection" 
                                                            message:msg delegate:self cancelButtonTitle:@"OK" 
                                                  otherButtonTitles:nil];
        [alertView show];


        NSArray *keys = [NSArray arrayWithObjects:@"firstname", @"lastname", nil];
        NSArray *objects = [NSArray arrayWithObjects:@"failed to", @"refresh data...", nil];
        NSDictionary *dictionary = [NSDictionary dictionaryWithObjects:objects forKeys:keys];

        allUsers = [[NSArray alloc] initWithObjects:dictionary, nil];
        //[self setUserData:allUsers];
        //[tblView reloadData];

        //[allUsers release];

    } 
    else
    {

        NSString *responseString = [[NSString alloc] initWithData:returnData encoding: NSUTF8StringEncoding];

        NSDictionary *results = [responseString JSONValue];
        // Additional steps as the webservice is adding an additional "{d:" so stripping of that
        NSString *extractUsers = [results objectForKey:@"d"];

        // The actual string that Web services returned, so re-scan the same and convert it as object
        NSDictionary *finalResult = [extractUsers JSONValue];
        allUsers = [finalResult objectForKey:@"users"];
        NSLog(@"Data is : %@",allUsers);
    开发者_运维知识库    NSLog(@"Final Value is : %@",[[allUsers objectAtIndex:0] valueForKey:@"lastname"]);
        if([allUsers count]>0)
        {
            label.text = [[allUsers objectAtIndex:0] valueForKey:@"lastname"];
        }
        else 
        {
            label.text = @"";
        }
        [responseString release];
        [request release];

    }




    [inProgressIndicator stopAnimating];
    [fileContents release];

    //Release all the allocated data
    [json release];

}

At first, you should check on which side delay is taking place - is it server's lag (maybe, not optimized DB usage or so on), internet-connection issue or another problem. Just trace and check, which line of code is executed for that minute at first.