Trivial case Login function for usergrid, using RestKit.

gistfile1.txt

- (void)login{
    NSURL *baseURL = [NSURL URLWithString:@"https://api.usergrid.com/[org]/[app]"];
    AFHTTPClient* client = [[AFHTTPClient alloc] initWithBaseURL:baseURL];
    [client setDefaultHeader:@"Accept" value:RKMIMETypeJSON];
    [client registerHTTPOperationClass:[AFJSONRequestOperation class]];
    NSDictionary *params = [[NSDictionary alloc] initWithObjectsAndKeys:
                            @"password",@"grant_type",
                            @"john.doe",@"username",
                            @"password",@"password",
                            nil];
    
    [client getPath:@"token"
         parameters:params
            success:^(AFHTTPRequestOperation *operation, id responseObject) {
                NSString *access_token = [responseObject objectForKey:@"access_token"];
                [[[RKObjectManager sharedManager] HTTPClient] setDefaultHeader:@"Authorization" value:[NSString stringWithFormat:@"Bearer %@", access_token]];

                [self postActivity];
                [self getFeed];
            }
            failure:^(AFHTTPRequestOperation *operation, NSError *error) {
                NSLog(@"%@",error);
            }];
}