def __call__(self, environ, start_response):
        path_info = environ['PATH_INFO']

        # Web app
        WEB_APP_PREFIX = '/w/'
        if path_info.startswith(WEB_APP_PREFIX):
            werkzeug.wsgi.pop_path_info(environ)
            return self.web_app(environ, start_response)

        # Admin redirect helpers.
        if path_info in ('/admin', '/admin/'):
            return self._redirect(environ, start_response, self.ADMIN_URL)

        if path_info.endswith(
            tuple(self.SYNTHESE_SUFFIXES + self.env.c.synthese_suffixes)):
            return self.proxy_app(environ, self.add_utf8_header(start_response))

        return self._handle_static_files(environ, start_response)