Get request parameters for redirect url.

def get_redirect_args(self, request, callback):
        "Get request parameters for redirect url."
        callback = force_text(request.build_absolute_uri(callback))
        raw_token = self.get_request_token(request, callback)
        token, secret = self.parse_raw_token(raw_token)
        if token is not None and secret is not None:
            request.session[self.session_key] = raw_token
        return {
            'oauth_token': token,
            'oauth_callback': callback,
        }