Facebook chatbots: what do they do? do they do things? let's find out

Exploration around conversational interfaces and finate state machines, as part of a nice hackathon trip to Sweden.

Prepare

Create a Facebook App and a Facebook Page, get the credentials, attach a webhook - e.g. with now, https://my-app.now.sh/messenger/webhook

Credentials (inject as environment variables):

• VERIFY_TOKEN: can be any string, need to be inserted here and in FB admin UI
• PAGE_TOKEN: get that from Messanger settings of your Facebook App admin UI
• FB_APP_SECRET: get that from your Facebook App admin UI

Develop

When in development, you can e.g. use ngrok to use as the webhook URL, e.g. https://e0931885.ngrok.io/messenger/webhook. Then run like this:

VERIFY_TOKEN=<token> PAGE_TOKEN=<token> FB_APP_SECRET=<token> DEBUG=botmaster:* yarn nodemon app.js

Chatbot description

Very simple indeed - waits to be greeted, invites to play a game, asks one question and waits for correct answer, then forgets you talked.

States diagram looks like this (generated using javascript-state-machine's visualisation feature and GraphvizOnline):

For "smart" features uses:

• Facebook's built-in NLP feature to detect user's greeting and saying bye
• Speakeasy package for detecting positive/negative sentiment on the answer
• yes-no-words package to guess if user confirmed or rejected

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