Parse JSON object in iOS app - ios

Question

Hi I am very new for Ios in my project I am integrating web services ok that's fine.
Here when I send proper request to the server, the response is coming from server like below "my first Response".
And if we send the wrong request to the server then response is coming from server like below "my second Response."
So we don't know which type of Json object we get from server after send request.
Here my main requirement is If we get proper response(like below first response) from server then we can save all elements which we want.
And if we get wrong response (like below second response) then how can we find and how to print that message because some times we get proper response and some times we get wrong response from server so how can we find and how can we save that response.
Please help me.
If send proper request then Response:-
responseObject = {
{
Name = Broad;
DeptNo = A00;
BatchNo = 23;
DeptId = 120;
},
{
Name = James;
DeptNo = B00;
BatchNo = 23;
DeptId = 123;
},
}
If we send wrong request then Response:-
responseObject = {
error = 1;
message = "Invalid Code";
}
my code:-
- (void)viewDidLoad {
[super viewDidLoad];
NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys:
#"12345678" ,#"scacode",
nil];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:#"my url"]
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:15.0];
[MBProgressHUD showHUDAddedTo:self.view animated:YES];
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Content-Type"];
[request setHTTPMethod:#"POST"];
NSURLSessionTask *task = [[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
dispatch_async(dispatch_get_main_queue(), ^{
[MBProgressHUD hideHUDForView:self.view animated:YES];
});
if (error) {
NSLog(#"dataTaskWithRequest error: %#", error);
}
if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
NSInteger statusCode = [(NSHTTPURLResponse *)response statusCode];
if (statusCode != 200) {
NSLog(#"Expected responseCode == 200; received %ld", (long)statusCode);
}
}
NSError *parseError;
id responseObject = [NSJSONSerialization JSONObjectWithData:data options:0 error:&parseError];
if (!responseObject) {
NSLog(#"JSON parse error: %#", parseError);
} else {
NSLog(#"responseObject = %#", responseObject);
}
}];
[task resume];
}

Answer 1

In your case you can use as following:
NSDictionary *responseObject = [NSJSONSerialization JSONObjectWithData:data options:0 error:&parseError];
if([responseObject objectForKey:#"error"] == nil)
{
//You are getting correct response
}
else{
// You are getting response with error
}

Answer 2

You can check response has a key with error. Otherwise you can use new variable in server side for all responses like statusCode. So if you get error or success, your server side can be set it to statusCode. It's very clear way for doing this.

Answer 3

You can use UIAlertView to display the error messages
if([responseObject objectForKey:#"error"] == nil)
{
//You are getting correct response
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Alert" message:#"Your Message" delegate:self cancelButtonTitle:#"Ok" otherButtonTitles:nil];
[alert show];
}
else
{
// You are getting response with error
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Alert" message:#"Error Message" delegate:self cancelButtonTitle:#"Ok" otherButtonTitles:nil];
[alert show];
}

Answer 4

I'm guessing you haven't posted whole responseObject(when sending proper request). Assuming that you're getting error=0 key when response is proper, you can do this:
NSMutableDictionary *jsonDictionary= [NSMutableDictionary alloc]init]
jsonDictionary=responseObject;
if([jsonDictionary valueForKey:#"error"]==#"0"]
{
//do some stuff
}
else
{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Error" message:#"Invalid Request" delegate:self cancelButtonTitle:#"Ok" otherButtonTitles:nil];
[alert show];
}