/**
* Request an access token from an OAuth 2.0 provider.
*
* <p>If it can be determined that the user has already granted access, and the token has not yet
* expired, and that the token will not expire soon, the existing token will be passed to the
* callback.
*
* <p>Otherwise, a popup window will be displayed which may prompt the user to grant access. If
* the user has already granted access the popup will immediately close and the token will be
* passed to the callback. If access hasn't been granted, the user will be prompted, and when they
* grant, the token will be passed to the callback.
*
* @param req Request for authentication.
* @param callback Callback to pass the token to when access has been granted.
*/
public void login(AuthRequest req, final Callback<String, Throwable> callback) {
lastRequest = req;
lastCallback = callback;
String authUrl = req.toUrl(urlCodex) + "&redirect_uri=" + urlCodex.encode(oauthWindowUrl);
// Try to look up the token we have stored.
final TokenInfo info = getToken(req);
if (info == null || info.expires == null || expiringSoon(info)) {
// Token wasn't found, or doesn't have an expiration, or is expired or
// expiring soon. Requesting access will refresh the token.
doLogin(authUrl, callback);
} else {
// Token was found and is good, immediately execute the callback with the
// access token.
scheduler.scheduleDeferred(
new ScheduledCommand() {
@Override
public void execute() {
callback.onSuccess(info.accessToken);
}
});
}
}
