How do i get the modhash and cookie from logging into reddit with the api? - objective-c

Question

NSString *username = #"username";
NSString *password = #"password";
NSURL *loginurl = [NSURL URLWithString:[NSString stringWithFormat:#"http://www.reddit.com/api/login/%#",username]];
NSMutableURLRequest *loginrequest = [NSMutableURLRequest requestWithURL:loginurl];
[loginrequest setHTTPMethod:#"POST"];
NSData *loginRequestBody = [[NSString stringWithFormat:#"api_type=json&user=%#&passwd=%#",username,password] dataUsingEncoding:NSUTF8StringEncoding];
[loginrequest setHTTPBody:loginRequestBody];
NSURLResponse *loginResponse = NULL;
NSError *loginRequestError = NULL;
NSData *loginResponseData = [NSURLConnection sendSynchronousRequest:loginrequest returningResponse:&loginResponse error:&loginRequestError];
NSString *loginResponseString = [[NSString alloc]initWithData:loginResponseData encoding:NSUTF8StringEncoding];
NSLog(#"%#",loginResponseString);
the NSLog prints this: (with some letters replaced)
{"json": {"errors": [], "data": {"modhash":
"j5hq16ukw2f17a9c153xxxxxxxxxa72ad989c96c904d49a97e", "cookie":
"13986184,2012-07-14T12:41:05,349f968b3089af75978xxxxxxxxxxxx761397ba0"}}}
How do i access the modhash and the cookie? I tried
[loginResponseData valueForKey:#"json"];
but it says that the class is not key value coding-compliant for the key json

Answer 1

loginResponseString is an NSString -- it doesn't know if it has JSON inside. You have to parse this JSON to an NSDictionary then you can use its methods to retrieve response data. Try my JSON parser: http://github.com/H2CO3/CarbonateJSON
Example using my CarbonateJSON library:
NSDictionary *parsedResponse = [loginResponseString parseJson];
NSString *modhash = [[[parsedResponse objectForKey:#"json"] objectForKey:#"data"] objectForKey:#"modhash"];

Answer 2

For anyone looking at this after me, you can check out H2CO3's solution, but I found that the easiest solution was using NSJSONSerialization to do it in a supported fashion.
NSError *error;
NSData *jsonData = [loginResponseString dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *loginResults = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error];
NSString *modhash = [[[loginResults valueForKey:#"json"] valueForKey:#"data"]valueForKey:#"modhash"];
worked for me.