Implement barebones conversation flow

[psiemens]

EventRouter

Receives an event from Facebook and passes it to the corresponding handler

Handler

Receives a Facebook event from the event router and returns an appropriate response.

PostbackHandler

Handles a postback event.

• Receive event from Facebook
• Parse campaign_id and event data from payload
• Retrieve user from database
• Update lastSeen and lastMessaged
• Retrieve campaign record using campaign_id (for demo this is the same every time)
• Find next node to send to user
• Send next node to user

Sample postback event:

{
  "sender":{
    "id":"USER_ID"
  },
  "recipient":{
    "id":"PAGE_ID"
  },
  "timestamp":1458692752478,
  "postback":{
    "payload": {
      "campaign_id": CAMPAIGN_ID,
      "event": {
        "type": "node",
        "target": "12F0EC20-924E-4476-B3CC-7514BB8A6913",
        "label": "Go to the next node"
      }
    }
    "referral": {
      "ref": USER_DEFINED_REFERRAL_PARAM,
      "source": "SHORTLINK",
      "type": "OPEN_THREAD",
    }
  }
}    

MessageHandler

Handles a message event.

For now, the message handler should have two possible behaviours:

• respond to the message "Start" by:
  • creating a new user record for the user if one doesn't already exist
  • sending the first node of the sample campaign
• respond to any other message with "I don't understand"

Sample message:

{
  "sender":{
    "id":"USER_ID"
  },
  "recipient":{
    "id":"PAGE_ID"
  },
  "timestamp":1458692752478,
  "message":{
    "mid":"mid.1457764197618:41d102a3e1ae206a38",
    "text":"hello, world!"
  }
}    

User Database

Stores information about users.

User record format:

{
  "userID": USER_ID_FROM_FACEBOOK,
  "lastSeen": LAST_SEEN_TIMESTAMP,
  "lastMessage": {
    "timestamp": LAST_MESSAGE_TIMESTAMP,
    "event": {
      "type": "node",
      "target": "12F0EC20-924E-4476-B3CC-7514BB8A6913",
      "label": "Go to the next node"
    }
  }
}

Acceptance Criteria

The chatbotfb program must:

• Open any JSON-formatted campaign, as specified in the Chatbot Management API Reference Documentation, stored in a file.
• Begin executing the campaign read from the file on program startup. The execution of the campaign should be in a function for that purpose, not main().
• Persist to a database any information necessary to support delivery of a campaign, as specified in the User Database section of this issue.
• Respond appropriately to postback events, taking whatever action is appropriate according to the campaign being delivered.