Question

I’m parsing json for a user authentication system.

If login is successful the server sends following user object;

{

    "users": {
        "id": "1",
        "FB_first_name": null,
        "FB_last_name": null,
        "FB_gender": null,
        "FB_id": null,
        "FB_link": null,
        "FB_locale": null,
        "FB_name": null,
        "FB_username": null,
        "created_at": "2011-01-02 08:30:59 UTC",
        "updated_at": "2011-01-02 08:31:23 UTC",
        "email": "[e-mail]",
        "language_id": "1"
    }

}

which I parse using the following code;

    NSDictionary *userDic = (NSDictionary*)[(NSDictionary*)results objectForKey:@"users"];

    User *aUser = [[User alloc] initWithID:[userDic objectForKey:@"id"]
                              withUserName:[userDic objectForKey:@"FB_name"]
                             withUserEmail:[userDic objectForKey:@"email"]
                             withUserFName:[userDic objectForKey:@"FB_first_name"]];

But in case of invalid user, the server sends following response;

[

    "Invalid Email or Password."

]

What if() statement should I use to parse and display the response in both conditions?

Answer 1

//parse out the json data
NSError* error;
id json = [NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingMutableContainers error:&error];
if ([json isKindOfClass:[NSArray class]){
    //You have to be sure that on error it returns array not a dictionary
    NSArray *arr = (NSArray*)json;
    NSString *errorMsg = [arr objectAtIndex:0];
}
else {

}