iOS Check for Token - ios

Question

I'm making an app that requires you to login in. I"m using JSON. So far I've been able send a POST request with the Username and Password and I get a token back (it shows up in the console). When I don't enter in the correct username/password combination, I don't get a token back. What I would like to happen is to proceed to the next view controller if I get a token back. I think that I need to use an if statement (I'll put the code for switching view controllers into it) but I don't know what parameters I need in order to check if I get a token back.
Here is the code I'm using in the implementation file. It is in a method that runs when a button is pressed:
#try {
if([[usernameTextField text] isEqualToString:#""] || [[passTextField text] isEqualToString:#""] ) {
[self alertStatus:#"Please enter both Username and Password" :#"Login Failed!"];
} else {
NSString *post =[[NSString alloc] initWithFormat:#"username=%#&password=%#",[usernameTextField text],[passTextField text]];
NSLog(#"PostData: %#",post);
NSURL *url=[NSURL URLWithString:#"https://beta.network360.com/tokens"];
NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
NSString *postLength = [NSString stringWithFormat:#"%d", [postData length]];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
[request setURL:url];
[request setHTTPMethod:#"POST"];
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
[request setValue:#"application/json" forHTTPHeaderField:#"Accept"];
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Content-Type"];
[request setHTTPBody:postData];
NSError *error = [[NSError alloc] init];
NSHTTPURLResponse *response = nil;
NSData *urlData=[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
NSLog(#"Response code: %d", [response statusCode]);
if ([response statusCode] >=200 && [response statusCode] <300)
{
NSString *responseData = [[NSString alloc]initWithData:urlData encoding:NSUTF8StringEncoding];
NSLog(#"Response ==> %#", responseData);
SBJsonParser *jsonParser = [SBJsonParser new];
NSDictionary *jsonData = (NSDictionary *) [jsonParser objectWithString:responseData error:nil];
NSLog(#"%#",jsonData);
NSInteger success = [(NSNumber *) [jsonData objectForKey:#"success"] integerValue];
NSLog(#"%d",success);
if(success == 1)
{
NSLog(#"Login SUCCESS");
[self alertStatus:#"Logged in Successfully." :#""];
} else {
NSString *error_msg = (NSString *) [jsonData objectForKey:#"error_message"];
[self alertStatus:error_msg :#"Login Failed!"];
}
} else {
if (error) NSLog(#"Error: %#", error);
[self alertStatus:#"Connection Failed" :#""];
}
}
}
#catch (NSException * e)
{
NSLog(#"Exception: %#", e);
[self alertStatus:#"Login Failed." :#""];
//[[PSearchViewController new] performSegueWithIdentifier:#"loginCancel" sender:self];
}
Also, here is what I get in the console output when I put in the correct username/password combination (BTW I tried to change all the stuff that showed up in the console that was confidential, so if some stuff doesn't quite match, it should be fine. I just wanted to show that I get a token back):
2013-07-28 13:23:21.607 Empyrean[28283:c07] PostData: username=username#gmail.com&password=password
2013-07-28 13:23:22.300 Empyrean[28283:c07] Response code: 200
2013-07-28 13:23:22.301 Empyrean[28283:c07] Response ==> {"token":"scFDzxSAVk2sxQBShEGS","user":{"id":300230,"username":"username#gmail.com","display_name":"FirstName LastName","unconfirmed_email":null,"email":"username#gmail.com","confirmation_email":"username#gmail.com","client_identifier":null,"client_id":138,"is_admin":false,"support_email":"support#supportemail.com","application_name":"AppName","show_project_vintage_date":false,"is_anonymous":false,"is_active":true,"is_confirmed":true,"pending_reconfirmation":false,"can_resend_confirmation":false,"client_name":"Broker","show_advertisements":true,"header_logo":"/foo/headerlogo.gif","report_footer_logo":"/stuff/foo/footerlogo.png","authorized_features":["find_stuff","do_stuff","stuff_stuff","settings","menu","manage_stuff","measure_stuff","export_stuff"],"url":"https://www.website.com/stuff/numbersdsjkflds"}}
2013-07-28 13:23:22.304 Empyrean[28283:c07] {
token = dlsfkasdfDfdsklfdDsa;
user = {
"application_name" = "Application Name";
"authorized_features" = (
"find_stuff",
"do_stuff",
"stuff_stuff",
settings,
menu,
"manage_stuff",
"measure_stuff",
"export_stuff"
);
"can_resend_confirmation" = 0;
"client_id" = 138;
"client_identifier" = "<null>";
"client_name" = Broker;
"confirmation_email" = "username#gmail.com";
"display_name" = "FirstName LastName";
email = "username#gmail.com";
"url" = "https://www.website.com/stuff/numbersdsjkflds";
"header_logo" = "/foo/headerlogo.gif";
id = 300230;
"is_active" = 1;
"is_admin" = 0;
"is_anonymous" = 0;
"is_confirmed" = 1;
"pending_reconfirmation" = 0;
"report_footer_logo" = "/stuff/foo/footerlogo.png";
"show_advertisements" = 1;
"show_project_vintage_date" = 0;
"support_email" = "support#supportemail.com";
"unconfirmed_email" = "<null>";
username = "username#gmail.com";
};
}

Answer 1

NSDictionary *jsonData is a dictionary. Therefore, you can see if the token key exists.
if (jsonData[#"token"])
{
// Token exists, so move on.
[self.navigationController pushViewController:nextController animated:YES];
}
else
{
// Tell the user they messed it up.
}