Retrieve OAuth access token.

    Used by flask-oauthlib to get the access token when making requests.

    :param remote: The remote application.
    :param token: Type of token to get. Data passed from ``oauth.request()`` to
        identify which token to retrieve. (Default: ``''``)
    :returns: The token.

def token_getter(remote, token=''):
    """Retrieve OAuth access token.

    Used by flask-oauthlib to get the access token when making requests.

    :param remote: The remote application.
    :param token: Type of token to get. Data passed from ``oauth.request()`` to
        identify which token to retrieve. (Default: ``''``)
    :returns: The token.
    """
    session_key = token_session_key(remote.name)

    if session_key not in session and current_user.is_authenticated:
        # Fetch key from token store if user is authenticated, and the key
        # isn't already cached in the session.
        remote_token = RemoteToken.get(
            current_user.get_id(),
            remote.consumer_key,
            token_type=token,
        )

        if remote_token is None:
            return None

        # Store token and secret in session
        session[session_key] = remote_token.token()

    return session.get(session_key, None)