Soundcloud OAuth request returns always invalid client - objective-c

Question

Here is my objective-c code to obtain access token from SoundCloud:
- (void) authoriseSoundcloud {
NSString *apiUrl = #"https://api.soundcloud.com/oauth2/token";
NSMutableURLRequest * urlRequest = [NSMutableURLRequest requestWithURL:[ NSURL URLWithString:apiUrl]];
NSString * params = [NSString stringWithFormat:#"client_id=%#&client_secret=%#grant_type=password&username=%#&password=%#",client,secretKey,fldUsername.text,fldPassword.text ];
[urlRequest setHTTPMethod:#"POST"];
[urlRequest setHTTPBody:[params dataUsingEncoding:NSUTF8StringEncoding]];
NSURLSession *defaultSession = [NSURLSession sharedSession];
NSURLSessionDataTask * dataTask =[defaultSession dataTaskWithRequest:urlRequest
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
NSLog(#"Response:%# %#\n", response, error);
if(error == nil)
{
NSString * text = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding];
NSLog(#"Data = %#",text);
}
}];
[dataTask resume];
}
However, I always get the result 401- {"error":"invalid_client"}.
However, that client ID works perfectly with those requests, that does not need authorization and I have checked multiple times, that my client ID and secret are correct.
As there is not much samples for iOS to use those parameters in HTTP post body, I assume that maybe my parameters list is incorrect. Any ideas from Soundcloud engineers?

Answer 1

Just a typo mistake, simply add "&" between "client_secret=%#" and "grant_type", like this :
NSString * params = [NSString stringWithFormat:#"client_id=%#&client_secret=%#&grant_type=password&username=%#&password=%#",client,secretKey,fldUsername.text,fldPassword.text ];
Work like a charm :)