Xmpp gtalk authentication with google access token - iphone

Question

I am using xmpp framework to integrate gtalk in my application. I have successfully authenticated user using OAuth 2.0. Now i want to use the access token and user email to authenticate xmpp stream. I know that the authentication call get sent xmppStreamDidConnect method using this method authenticateWithPassword. This requires a password, i want to get it done using the google access token. Any help?

Answer 1

Yes you can do it please follow the steps:
Register your app on google developer console.
Generate access token with following scope:
https://www.googleapis.com/auth/googletalk
start authentication as following:
(BOOL)start:(NSError **)errPtr
{
XMPPLogTrace();
// From RFC 4616 - PLAIN SASL Mechanism:
// [authzid] UTF8NUL authcid UTF8NUL passwd
//
// authzid: authorization identity
// authcid: authentication identity (username)
// passwd : password for authcid
NSString *accessToken = #"ACCESS-TOKEN-STRING-FROM Google";//TODO: assign your generated access token
NSLog(#"stream supports: %#",xmppStream.supportedAuthenticationMechanisms);
NSString *payload = [NSString stringWithFormat:#"\0%#\0%#", xmppStream.hostName, accessToken];
NSLog(#"payload = %#",payload);
NSString *base64 = [[payload dataUsingEncoding:NSUTF8StringEncoding] xmpp_base64Encoded];
NSXMLElement *auth = [NSXMLElement elementWithName:#"auth" xmlns:#"urn:ietf:params:xml:ns:xmpp-sasl"];
[auth addAttributeWithName:#"mechanism" stringValue:#"X-OAUTH2"];
[auth addAttributeWithName:#"auth:service" stringValue:#"oauth2"];
[auth addAttributeWithName:#"xmlns:auth" stringValue:#"https://www.google.com/talk/protocol/auth"];
[auth setStringValue:base64];
[xmppStream sendAuthElement:auth];
return YES;
}
Everything should work as expected, please comment.