code: function(req){
      var token = null;
      if (req.headers && req.headers.authorization) {
        var parts = req.headers.authorization.split(' ');
        if (parts.length === 2){
          var scheme = parts[0];
          var credentials = parts[1];
  
          if (/^Bearer$/i.test(scheme)){
             token = credentials;
          }
        }
      }else{
        token = this.allParams(req).access_token;
      }
      return token;
    }
docs: Return access token from request
  
  @param  {Object} req the express request object
  @return {String} token
  @api public