Handles mark message as read request.

    :param Request request:
    :param int message_id:
    :param int dispatch_id:
    :param str hashed:
    :param str redirect_to:
    :return:

def mark_read(request, message_id, dispatch_id, hashed, redirect_to=None):
    """Handles mark message as read request.

    :param Request request:
    :param int message_id:
    :param int dispatch_id:
    :param str hashed:
    :param str redirect_to:
    :return:
    """
    if redirect_to is None:
        redirect_to = get_static_url('img/sitemessage/blank.png')

    return _generic_view(
        'handle_mark_read_request', sig_mark_read_failed,
        request, message_id, dispatch_id, hashed, redirect_to=redirect_to
    )