Google oauth 2.0 refreshing access token - iphone

Question

How to get a new access token in Google Oauth 2.0?
I tried this:
NSString * urlString1 = [NSString stringWithFormat:#"https://accounts.google.com/o/oauth2/token?client_id=my_client_id&client_secret=my_client_secret&refresh_token=%#&grant_type=refresh_token",auth.refreshToken];
NSURL * url = [NSURL URLWithString:urlString1];
NSMutableURLRequest * request = [[NSMutableURLRequest alloc] initWithURL:url];
[request addValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Content-Type"];
[request setHTTPMethod:#"POST"];
NSURLConnection * connection = [[NSURLConnection alloc]initWithRequest:request delegate:self];
[connection start];
But result is: Method Not Allowed (Error 405)
Maybe there is another way to get new access token?
Please help!
Thanks!

Answer 1

HTTP 405 means that you are trying to use a verb that is not allowed by the resource. For example using a POST on a read-only GET resource or PUT on a write resource that only accepts POSTs.
See abraham's answer : Google with oauth 2

Answer 2

please use following code to get access token in Google Plus
First Replase you - (NSString *)description method in GTMOAuth2Authentication.h file and you will surely get G+ Acccess token
- (NSString *)description
{
NSArray *props = [NSArray arrayWithObjects:#"accessToken",nil];//[NSArray arrayWithObjects:#"accessToken", #"refreshToken",#"code", #"assertion", #"expirationDate", #"errorString",nil];
NSMutableString *valuesStr = [NSMutableString string];
NSString *separator = #"";
for (NSString *prop in props) {
id result = [self valueForKey:prop];
if (result)
{
[valuesStr appendFormat:#"%#",result];
separator = #", ";
}
}
return [NSString stringWithFormat:#"%#",valuesStr];
}
in .h file
#class GPPSignInButton;
#interface GPlusView : UIViewController <GPPSignInDelegate>
{
IBOutlet GPPSignInButton *signInButton;
}
#property (retain, nonatomic) IBOutlet GPPSignInButton *signInButton;
in .m file
signInButton_.shouldFetchGoogleUserEmail = TRUE;
signInButton_.delegate = self;
signInButton_.clientID = [SamacharAppDelegate clientID];
signInButton_.scope = [NSArray arrayWithObjects:
#"https://www.googleapis.com/auth/plus.me",
nil];
-(void)finishedWithAuth:(GTMOAuth2Authentication *)auth error:(NSError *)error
{
if (error) {
NSLog(#"Error = %#",error.localizedDescription);
return;
}
NSLog("Auth Data = %#",auth);
/* Auth Data = {accessToken="ya29.AHES6ZQYLmSBc9n4pLj9U8OQrFoTDZnGLH8okPkxbda7B0Q", refreshToken="1/puItTB-sqHupfp9qPCKcb6_gWUjgcxwzc9TKJvUwMEI", expirationDate="2012-11-24 13:30:55 +0000"} */
}