Chat bot on Google Cloud Function for FB

[constructor-igor]

moved to https://github.com/constructor-igor/HebrewCalendarBots/issues/1

https://aws.amazon.com/blogs/compute/create-and-deploy-a-chat-bot-to-aws-lambda-in-five-minutes/ https://blog.alana.cloud/lets-code-a-serverless-chatbot-for-facebook-messenger-8551c3ee7e6 https://serverless.com/blog/building-a-facebook-messenger-chatbot-with-serverless/ https://github.com/GoogleCloudPlatform/cloud-functions-emulator

https://developers.facebook.com/docs/messenger-platform/guides/quick-start FB chat bot (java script) sample: https://github.com/constructor-igor/messenger-platform-samples

[constructor-igor]

[constructor-igor]

/**
 * Responds to any HTTP request that can provide a "message" field in the body.
 *
 * @param {!Object} req Cloud Function request context.
 * @param {!Object} res Cloud Function response context.
 */

const 
  request = require('request');

const PAGE_ACCESS_TOKEN = PAGE_ACCESS_TOKEN from FaceBook
const VERIFY_TOKEN = VERIFY_TOKEN from Facebook

exports.helloWorld = function helloWorld(req, res) {
    if (req.method === 'GET') {
      console.log('Received a verify request with token', req.query['hub.verify_token']);
      if (req.query['hub.verify_token'] === VERIFY_TOKEN) {
        return res.send(req.query['hub.challenge']);
      }
      return res.send('Error, wrong validation token');
  }

  var data = req.body;
  if (data.object === 'page') {
    data.entry.forEach(function(entry) {
      var pageID = entry.id;
      var timeOfEvent = entry.time;

      // Iterate over each messaging event
      entry.messaging.forEach(function(event) {
        if (event.message) {
          receivedMessage(event);
        } else {
          console.log("Webhook received unknown event: ", event);
        }
      });
    });
  }

//  const messagingEvents = flatten(req.body.entry.map(entry => entry.messaging));
//  console.log(`Recieved ${messagingEvents.length} messages`);
  res.sendStatus(200);
};

function receivedMessage0(event) {
  // Putting a stub for now, we'll expand it in the following steps
  console.log("Message data: ", event.message);
}

function receivedMessage(event) {
  var senderID = event.sender.id;
  var recipientID = event.recipient.id;
  var timeOfMessage = event.timestamp;
  var message = event.message;

  console.log("Received message for user %d and page %d at %d with message:", 
    senderID, recipientID, timeOfMessage);
  console.log(JSON.stringify(message));

  var messageId = message.mid;

  var messageText = message.text;
  var messageAttachments = message.attachments;

  if (messageText) {

    // If we receive a text message, check to see if it matches a keyword
    // and send back the example. Otherwise, just echo the text we received.
    switch (messageText) {
      case 'generic':
        sendGenericMessage(senderID);
        break;

      default:
        sendTextMessage(senderID, messageText);
    }
  } else if (messageAttachments) {
    sendTextMessage(senderID, "Message with attachment received");
  }
}

function sendGenericMessage(recipientId, messageText) {
  // To be expanded in later sections
}

function sendTextMessage(recipientId, messageText) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      text: messageText
    }
  };

  callSendAPI(messageData);
}

function callSendAPI(messageData) {
  request({
    uri: 'https://graph.facebook.com/v2.6/me/messages',
    qs: { access_token: PAGE_ACCESS_TOKEN },
    method: 'POST',
    json: messageData

  }, function (error, response, body) {
    if (!error && response.statusCode == 200) {
      var recipientId = body.recipient_id;
      var messageId = body.message_id;

      console.log("Successfully sent generic message with id %s to recipient %s", 
        messageId, recipientId);
    } else {
      console.error("Unable to send message.");
      console.error(response);
      console.error(error);
    }
  });  
}

[constructor-igor]

package.json

{
    "name": "sample-http",
    "version": "0.0.1",
    "dependencies": {
        "request": "^2.72.0"
    }
}

[constructor-igor]

https://stackoverflow.com/questions/36851079/payload-option-on-facebook-bots-buttons

postback

[constructor-igor]

function UserAction() {
    var xhttp = new XMLHttpRequest();
    xhttp.open("POST", "Your Rest URL Here", false);
    xhttp.setRequestHeader("Content-type", "application/json");
    xhttp.send();
    var response = JSON.parse(xhttp.responseText);
}