app.js

/*
 * Copyright 2016-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the license found in the
 * LICENSE file in the root directory of this source tree.
 *
 */

/* jshint node: true, devel: true */
"use strict";

const bodyParser = require("body-parser"),
  config = require("config"),
  crypto = require("crypto"),
  express = require("express"),
  https = require("https"),
  request = require("request");

var app = express();
app.set("port", process.env.PORT || 5000);
app.set("view engine", "ejs");
app.use(bodyParser.json({ verify: verifyRequestSignature }));
app.use(express.static("public"));

var handlers = require("./handlers/index.js");

/*
 * Be sure to setup your config values before running this code. You can
 * set them using environment variables or modifying the config file in /config.
 *
 */

// App Secret can be retrieved from the App Dashboard
const APP_SECRET = process.env.MESSENGER_APP_SECRET
  ? process.env.MESSENGER_APP_SECRET
  : config.get("appSecret");

// Arbitrary value used to validate a webhook
const VALIDATION_TOKEN = process.env.MESSENGER_VALIDATION_TOKEN
  ? process.env.MESSENGER_VALIDATION_TOKEN
  : config.get("validationToken");

// Generate a page access token for your page from the App Dashboard
const PAGE_ACCESS_TOKEN = process.env.MESSENGER_PAGE_ACCESS_TOKEN
  ? process.env.MESSENGER_PAGE_ACCESS_TOKEN
  : config.get("pageAccessToken");

// URL where the app is running (include protocol). Used to point to scripts and
// assets located at this address.
const SERVER_URL = process.env.SERVER_URL
  ? process.env.SERVER_URL
  : config.get("serverURL");

if (!(APP_SECRET && VALIDATION_TOKEN && PAGE_ACCESS_TOKEN && SERVER_URL)) {
  console.error("Missing config values");
  process.exit(1);
}

/*
 * Use your own validation token. Check that the token used in the Webhook
 * setup is the same token used here.
 *
 */
app.get("/webhook", function(req, res) {
  if (
    req.query["hub.mode"] === "subscribe" &&
    req.query["hub.verify_token"] === VALIDATION_TOKEN
  ) {
    console.log("Validating webhook");
    res.status(200).send(req.query["hub.challenge"]);
  } else {
    console.error("Failed validation. Make sure the validation tokens match.");
    res.sendStatus(403);
  }
});

/*
 * All callbacks for Messenger are POST-ed. They will be sent to the same
 * webhook. Be sure to subscribe your app to your page to receive callbacks
 * for your page.
 * https://developers.facebook.com/docs/messenger-platform/product-overview/setup#subscribe_app
 *
 */
app.post("/webhook", function(req, res) {
  var data = req.body;

  // Make sure this is a page subscription
  if (data.object == "page") {
    // Iterate over each entry
    // There may be multiple if batched
    data.entry.forEach(function(pageEntry) {
      var pageID = pageEntry.id;
      var timeOfEvent = pageEntry.time;

      // Iterate over each messaging event
      pageEntry.messaging.forEach(function(messagingEvent) {
        if (messagingEvent.optin) {
          receivedAuthentication(messagingEvent);
        } else if (messagingEvent.message) {
          receivedMessage(messagingEvent);
        } else if (messagingEvent.delivery) {
          receivedDeliveryConfirmation(messagingEvent);
        } else if (messagingEvent.postback) {
          receivedPostback(messagingEvent);
        } else if (messagingEvent.read) {
          receivedMessageRead(messagingEvent);
        } else if (messagingEvent.account_linking) {
          receivedAccountLink(messagingEvent);
        } else {
          console.log(
            "Webhook received unknown messagingEvent: ",
            messagingEvent
          );
        }
      });
    });

    // Assume all went well.
    //
    // You must send back a 200, within 20 seconds, to let us know you've
    // successfully received the callback. Otherwise, the request will time out.
    res.sendStatus(200);
  }
});

/*
 * This path is used for account linking. The account linking call-to-action
 * (sendAccountLinking) is pointed to this URL.
 *
 */
app.get("/authorize", function(req, res) {
  var accountLinkingToken = req.query.account_linking_token;
  var redirectURI = req.query.redirect_uri;

  // Authorization Code should be generated per user by the developer. This will
  // be passed to the Account Linking callback.
  var authCode = "1234567890";

  // Redirect users to this URI on successful login
  var redirectURISuccess = redirectURI + "&authorization_code=" + authCode;

  res.render("authorize", {
    accountLinkingToken: accountLinkingToken,
    redirectURI: redirectURI,
    redirectURISuccess: redirectURISuccess
  });
});

/*
 * Verify that the callback came from Facebook. Using the App Secret from
 * the App Dashboard, we can verify the signature that is sent with each
 * callback in the x-hub-signature field, located in the header.
 *
 * https://developers.facebook.com/docs/graph-api/webhooks#setup
 *
 */
function verifyRequestSignature(req, res, buf) {
  var signature = req.headers["x-hub-signature"];

  if (!signature) {
    // For testing, let's log an error. In production, you should throw an
    // error.
    console.error("Couldn't validate the signature.");
  } else {
    var elements = signature.split("=");
    var method = elements[0];
    var signatureHash = elements[1];

    var expectedHash = crypto
      .createHmac("sha1", APP_SECRET)
      .update(buf)
      .digest("hex");

    if (signatureHash != expectedHash) {
      throw new Error("Couldn't validate the request signature.");
    }
  }
}

/*
 * Authorization Event
 *
 * The value for 'optin.ref' is defined in the entry point. For the "Send to
 * Messenger" plugin, it is the 'data-ref' field. Read more at
 * https://developers.facebook.com/docs/messenger-platform/webhook-reference/authentication
 *
 */
function receivedAuthentication(event) {
  var senderID = event.sender.id;
  var recipientID = event.recipient.id;
  var timeOfAuth = event.timestamp;

  // The 'ref' field is set in the 'Send to Messenger' plugin, in the 'data-ref'
  // The developer can set this to an arbitrary value to associate the
  // authentication callback with the 'Send to Messenger' click event. This is
  // a way to do account linking when the user clicks the 'Send to Messenger'
  // plugin.
  var passThroughParam = event.optin.ref;

  console.log(
    "Received authentication for user %d and page %d with pass " +
      "through param '%s' at %d",
    senderID,
    recipientID,
    passThroughParam,
    timeOfAuth
  );

  // When an authentication is received, we'll send a message back to the sender
  // to let them know it was successful.
  sendTextMessage(senderID, "Authentication successful");
}

/*
 * Message Event
 *
 * This event is called when a message is sent to your page. The 'message'
 * object format can vary depending on the kind of message that was received.
 * Read more at https://developers.facebook.com/docs/messenger-platform/webhook-reference/message-received
 *
 * For this example, we're going to echo any text that we get. If we get some
 * special keywords ('button', 'generic', 'receipt'), then we'll send back
 * examples of those bubbles to illustrate the special message bubbles we've
 * created. If we receive a message with an attachment (image, video, audio),
 * then we'll simply confirm that we've received the attachment.
 *
 */
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 isEcho = message.is_echo;
  var messageId = message.mid;
  var appId = message.app_id;
  var metadata = message.metadata;

  // You may get a text or attachment but not both
  var messageText = message.text;
  var messageAttachments = message.attachments;
  var quickReply = message.quick_reply;

  if (isEcho) {
    // Just logging message echoes to console
    console.log(
      "Received echo for message %s and app %d with metadata %s",
      messageId,
      appId,
      metadata
    );
    return;
  } else if (quickReply) {
    var quickReplyPayload = quickReply.payload;
    console.log(
      "Quick reply for message %s with payload %s",
      messageId,
      quickReplyPayload
    );

    sendTextMessage(senderID, "Quick reply tapped");
    return;
  }

  if (messageText) {
    // If we receive a text message, check to see if it matches any special
    // keywords and send back the corresponding example. Otherwise, just echo
    // the text we received.
    switch (messageText) {
      /*case "image":
        sendImageMessage(senderID);
        break;

      case "gif":
        sendGifMessage(senderID);
        break;

      case "audio":
        sendAudioMessage(senderID);
        break;

      case "video":
        sendVideoMessage(senderID);
        break;

      case "file":
        sendFileMessage(senderID);
        break;

      case "button":
        sendButtonMessage(senderID);
        break;

      case "generic":
        sendGenericMessage(senderID);
        break;

      case "receipt":
        sendReceiptMessage(senderID);
        break;

      case "quick reply":
        sendQuickReply(senderID);
        break;

      case "read receipt":
        sendReadReceipt(senderID);
        break;

      case "typing on":
        sendTypingOn(senderID);
        break;

      case "typing off":
        sendTypingOff(senderID);
        break;

      case "account linking":
        sendAccountLinking(senderID);
        break;
      */
      default:
        let req = new Promise((res, rej) => res(handlers.text(messageText)));
        req.then(body => sendTextMessage(senderID, body));
    }
  } else if (messageAttachments) {
    sendTextMessage(senderID, "Message with attachment received");
  }
}

/*
 * Delivery Confirmation Event
 *
 * This event is sent to confirm the delivery of a message. Read more about
 * these fields at https://developers.facebook.com/docs/messenger-platform/webhook-reference/message-delivered
 *
 */
function receivedDeliveryConfirmation(event) {
  var senderID = event.sender.id;
  var recipientID = event.recipient.id;
  var delivery = event.delivery;
  var messageIDs = delivery.mids;
  var watermark = delivery.watermark;
  var sequenceNumber = delivery.seq;

  if (messageIDs) {
    messageIDs.forEach(function(messageID) {
      console.log(
        "Received delivery confirmation for message ID: %s",
        messageID
      );
    });
  }

  console.log("All message before %d were delivered.", watermark);
}

/*
 * Postback Event
 *
 * This event is called when a postback is tapped on a Structured Message.
 * https://developers.facebook.com/docs/messenger-platform/webhook-reference/postback-received
 *
 */
function receivedPostback(event) {
  var senderID = event.sender.id;
  var recipientID = event.recipient.id;
  var timeOfPostback = event.timestamp;

  // The 'payload' param is a developer-defined field which is set in a postback
  // button for Structured Messages.
  var payload = event.postback.payload;

  console.log(
    "Received postback for user %d and page %d with payload '%s' " + "at %d",
    senderID,
    recipientID,
    payload,
    timeOfPostback
  );

  // When a postback is called, we'll send a message back to the sender to
  // let them know it was successful
  sendTextMessage(senderID, "Postback called");
}

/*
 * Message Read Event
 *
 * This event is called when a previously-sent message has been read.
 * https://developers.facebook.com/docs/messenger-platform/webhook-reference/message-read
 *
 */
function receivedMessageRead(event) {
  var senderID = event.sender.id;
  var recipientID = event.recipient.id;

  // All messages before watermark (a timestamp) or sequence have been seen.
  var watermark = event.read.watermark;
  var sequenceNumber = event.read.seq;

  console.log(
    "Received message read event for watermark %d and sequence " + "number %d",
    watermark,
    sequenceNumber
  );
}

/*
 * Account Link Event
 *
 * This event is called when the Link Account or UnLink Account action has been
 * tapped.
 * https://developers.facebook.com/docs/messenger-platform/webhook-reference/account-linking
 *
 */
function receivedAccountLink(event) {
  var senderID = event.sender.id;
  var recipientID = event.recipient.id;

  var status = event.account_linking.status;
  var authCode = event.account_linking.authorization_code;

  console.log(
    "Received account link event with for user %d with status %s " +
      "and auth code %s ",
    senderID,
    status,
    authCode
  );
}

/*
 * Send an image using the Send API.
 *
 */
function sendImageMessage(recipientId) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      attachment: {
        type: "image",
        payload: {
          url: SERVER_URL + "/assets/rift.png"
        }
      }
    }
  };

  callSendAPI(messageData);
}

/*
 * Send a Gif using the Send API.
 *
 */
function sendGifMessage(recipientId) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      attachment: {
        type: "image",
        payload: {
          url: SERVER_URL + "/assets/instagram_logo.gif"
        }
      }
    }
  };

  callSendAPI(messageData);
}

/*
 * Send audio using the Send API.
 *
 */
function sendAudioMessage(recipientId) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      attachment: {
        type: "audio",
        payload: {
          url: SERVER_URL + "/assets/sample.mp3"
        }
      }
    }
  };

  callSendAPI(messageData);
}

/*
 * Send a video using the Send API.
 *
 */
function sendVideoMessage(recipientId) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      attachment: {
        type: "video",
        payload: {
          url: SERVER_URL + "/assets/allofus480.mov"
        }
      }
    }
  };

  callSendAPI(messageData);
}

/*
 * Send a file using the Send API.
 *
 */
function sendFileMessage(recipientId) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      attachment: {
        type: "file",
        payload: {
          url: SERVER_URL + "/assets/test.txt"
        }
      }
    }
  };

  callSendAPI(messageData);
}

/*
 * Send a text message using the Send API.
 *
 */
function sendTextMessage(recipientId, messageText) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      text: messageText,
      metadata: "DEVELOPER_DEFINED_METADATA"
    }
  };

  callSendAPI(messageData);
}

/*
 * Send a button message using the Send API.
 *
 */
function sendButtonMessage(recipientId) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      attachment: {
        type: "template",
        payload: {
          template_type: "button",
          text: "This is test text",
          buttons: [
            {
              type: "web_url",
              url: "https://www.oculus.com/en-us/rift/",
              title: "Open Web URL"
            },
            {
              type: "postback",
              title: "Trigger Postback",
              payload: "DEVELOPER_DEFINED_PAYLOAD"
            },
            {
              type: "phone_number",
              title: "Call Phone Number",
              payload: "+16505551234"
            }
          ]
        }
      }
    }
  };

  callSendAPI(messageData);
}

/*
 * Send a Structured Message (Generic Message type) using the Send API.
 *
 */
function sendGenericMessage(recipientId) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      attachment: {
        type: "template",
        payload: {
          template_type: "generic",
          elements: [
            {
              title: "rift",
              subtitle: "Next-generation virtual reality",
              item_url: "https://www.oculus.com/en-us/rift/",
              image_url: SERVER_URL + "/assets/rift.png",
              buttons: [
                {
                  type: "web_url",
                  url: "https://www.oculus.com/en-us/rift/",
                  title: "Open Web URL"
                },
                {
                  type: "postback",
                  title: "Call Postback",
                  payload: "Payload for first bubble"
                }
              ]
            },
            {
              title: "touch",
              subtitle: "Your Hands, Now in VR",
              item_url: "https://www.oculus.com/en-us/touch/",
              image_url: SERVER_URL + "/assets/touch.png",
              buttons: [
                {
                  type: "web_url",
                  url: "https://www.oculus.com/en-us/touch/",
                  title: "Open Web URL"
                },
                {
                  type: "postback",
                  title: "Call Postback",
                  payload: "Payload for second bubble"
                }
              ]
            }
          ]
        }
      }
    }
  };

  callSendAPI(messageData);
}

/*
 * Send a receipt message using the Send API.
 *
 */
function sendReceiptMessage(recipientId) {
  // Generate a random receipt ID as the API requires a unique ID
  var receiptId = "order" + Math.floor(Math.random() * 1000);

  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      attachment: {
        type: "template",
        payload: {
          template_type: "receipt",
          recipient_name: "Peter Chang",
          order_number: receiptId,
          currency: "USD",
          payment_method: "Visa 1234",
          timestamp: "1428444852",
          elements: [
            {
              title: "Oculus Rift",
              subtitle: "Includes: headset, sensor, remote",
              quantity: 1,
              price: 599.00,
              currency: "USD",
              image_url: SERVER_URL + "/assets/riftsq.png"
            },
            {
              title: "Samsung Gear VR",
              subtitle: "Frost White",
              quantity: 1,
              price: 99.99,
              currency: "USD",
              image_url: SERVER_URL + "/assets/gearvrsq.png"
            }
          ],
          address: {
            street_1: "1 Hacker Way",
            street_2: "",
            city: "Menlo Park",
            postal_code: "94025",
            state: "CA",
            country: "US"
          },
          summary: {
            subtotal: 698.99,
            shipping_cost: 20.00,
            total_tax: 57.67,
            total_cost: 626.66
          },
          adjustments: [
            {
              name: "New Customer Discount",
              amount: -50
            },
            {
              name: "$100 Off Coupon",
              amount: -100
            }
          ]
        }
      }
    }
  };

  callSendAPI(messageData);
}

/*
 * Send a message with Quick Reply buttons.
 *
 */
function sendQuickReply(recipientId) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      text: "What's your favorite movie genre?",
      quick_replies: [
        {
          content_type: "text",
          title: "Action",
          payload: "DEVELOPER_DEFINED_PAYLOAD_FOR_PICKING_ACTION"
        },
        {
          content_type: "text",
          title: "Comedy",
          payload: "DEVELOPER_DEFINED_PAYLOAD_FOR_PICKING_COMEDY"
        },
        {
          content_type: "text",
          title: "Drama",
          payload: "DEVELOPER_DEFINED_PAYLOAD_FOR_PICKING_DRAMA"
        }
      ]
    }
  };

  callSendAPI(messageData);
}

/*
 * Send a read receipt to indicate the message has been read
 *
 */
function sendReadReceipt(recipientId) {
  console.log("Sending a read receipt to mark message as seen");

  var messageData = {
    recipient: {
      id: recipientId
    },
    sender_action: "mark_seen"
  };

  callSendAPI(messageData);
}

/*
 * Turn typing indicator on
 *
 */
function sendTypingOn(recipientId) {
  console.log("Turning typing indicator on");

  var messageData = {
    recipient: {
      id: recipientId
    },
    sender_action: "typing_on"
  };

  callSendAPI(messageData);
}

/*
 * Turn typing indicator off
 *
 */
function sendTypingOff(recipientId) {
  console.log("Turning typing indicator off");

  var messageData = {
    recipient: {
      id: recipientId
    },
    sender_action: "typing_off"
  };

  callSendAPI(messageData);
}

/*
 * Send a message with the account linking call-to-action
 *
 */
function sendAccountLinking(recipientId) {
  var messageData = {
    recipient: {
      id: recipientId
    },
    message: {
      attachment: {
        type: "template",
        payload: {
          template_type: "button",
          text: "Welcome. Link your account.",
          buttons: [
            {
              type: "account_link",
              url: SERVER_URL + "/authorize"
            }
          ]
        }
      }
    }
  };

  callSendAPI(messageData);
}

/*
 * Call the Send API. The message data goes in the body. If successful, we'll
 * get the message id in a response
 *
 */
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;

        if (messageId) {
          console.log(
            "Successfully sent message with id %s to recipient %s",
            messageId,
            recipientId
          );
        } else {
          console.log(
            "Successfully called Send API for recipient %s",
            recipientId
          );
        }
      } else {
        console.error(
          "Failed calling Send API",
          response.statusCode,
          response.statusMessage,
          body.error
        );
      }
    }
  );
}

// Start server
// Webhooks must be available via SSL with a certificate signed by a valid
// certificate authority.
app.listen(app.get("port"), function() {
  console.log("Node app is running on port", app.get("port"));
});

module.exports = app;