Extending the wingbot's abilities using Processor plugin

To be able to:

• add methods to Request or Responder
• modify state before save

you can use a Processor plugin

Processor plugin

Processor plugin has following interface and all functions can be async or not.

• #processMessage(message, pageId, messageSender)

  Called immediately after the messaging event arrives to Processor. Has following signature:

  • message: object - the messaging event object
  • pageId: string - id of page (channel), where the event occured
  • messageSender: Sender - an instance of Sender class, which allows to send responses
  • returns: {status:number} - status 200 will stop the dispatching and will be returned

• #beforeAiPreload(req, res): boolean

  Called immediately after loading the state and before the intent or entities are attached and also before the "setState" from quick replies is processed.

  Returning false stops the dispatching.

• #beforeProcessMessage(req, res): boolean

  Called just before passing a message through bot.

  Returning false stops the dispatching.

• #afterProcessMessage(req, res)

  Called after the bot completes dispatching an event. Allows to modify state before it'll be stored.

Using the plugin

This example shows how to implement own state property and it's setter, so the data will be persisted.

class MySpecialStatePlugin {

    beforeProcessMessage (req, res) {
        Object.assign(req, {
            mySpecialState: req.state._mySpecState
        });
        Object.assign(res, {
            _updateMySpecialState: {},
            setMySpecialState (data) {
                Object.assign(this._updateMySpecialState, data);
            }
        });
        return true;
    }

    afterProcessMessage (req, res) {
        res.setState({
            _mySpecState: {
                ...req.mySpecialState,
                ...res._updateMySpecialState
            }
        });
    }

}

// using the plugin
const bot = new Router();

bot.use('start', (req, res) => {
    res.setMySpecialState({ visitedStart: true });
});

// register the plugin in processor
const processor = new Processor(bot);

processor.plugin(new MySpecialStatePlugin());