iOS - Authenticate with Google and send the token to server for syncing

Question

I'm working with iOS application which is used to authenticate with Google oAuth2 mechanism. After successfully authentication, i've to send code/token to the server for handling the sync of files, calendars, etc.
I'm able to successfully authenticate with google using their latest library/framework.
But after authentication, i got the token/code which I can send to server. But when server is using the code to authenticate with google, its failing.
Is there any other API to handle this?

Answer 1

It's very broad theme :) In some cases there's enough to add token data to URL, like LinkedIn, for example:

NSString *requestURLString = [@"https://api.linkedin.com/v1/people/~/shares?oauth2_access_token=" stringByAppendingString:@"LI_access_token"];

And in some cases adding corresponding fields to HTTP POST-request is necessary, like posting Facebook like for example:

postString = [NSString stringWithFormat:@"\r\n--%@\r\n", boundary];
postString = [postString stringByAppendingString:@"Content-Disposition: form-data; name=\"access_token\"\r\n\r\n"];
postString = [postString stringByAppendingString:FBSession.activeSession.accessTokenData.accessToken];

Or adding additional fields to HTTP-request header is needed, like SoundCloud, for example:

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:requestURL] cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData timeoutInterval:60.0f];
[request setHTTPMethod:@"GET"];
[request setValue:[@"OAuth " stringByAppendingString:self.accessToken] forHTTPHeaderField:@"Authorization"];

Try to clarify your case with documentation of used API.