# Masked Phone Numbers with Node.js and Express

This [Express](https://expressjs.com/) sample application models an amazing rental experience that a vacation rental company might provide, but with more [Klingons](https://en.wikipedia.org/wiki/Klingon).

Host users can offer rental properties which other guest users can reserve. The guest and the host can then anonymously communicate via a disposable Twilio phone number created just for a reservation. In this tutorial, we'll show you the key bits of code to make this work.

To run this sample app yourself, download the code and follow the [instructions on GitHub](https://github.com/TwilioDevEd/airtng-node/tree/masked-numbers).

> \[!WARNING]
>
> If you choose to manage communications between your users, including voice calls, text-based messages (e.g., SMS), and chat, you may need to comply with certain laws and regulations, including those regarding obtaining consent. Additional information regarding legal compliance considerations and best practices for using Twilio to manage and record communications between your users, such as when using Twilio Proxy, can be found [here](https://help.twilio.com/hc/en-us/articles/360011435554-Best-Practices-for-Using-Twilio-to-Manage-and-Record-Communications-Between-Users).
>
> *Notice*: Twilio recommends that you consult with your legal counsel to make sure that you are complying with all applicable laws in connection with communications you record or store using Twilio.

*[Read how Lyft uses masked phone numbers to let customers securely contact drivers.](https://customers.twilio.com/249/lyft/)*

## Create a Reservation

The first step in connecting a guest and host is creating a reservation. Here we handle a form submission for a new reservation which contains the message and the *guest's* information which is grabbed from the logged in user.

```js title="Create a Reservation" description="routes/reservations.js"
// !mark(25:47)
var twilio = require('twilio');
var MessagingResponse = require('twilio').twiml.MessagingResponse;
var express = require('express');
var router = express.Router();
var Property = require('../models/property');
var Reservation = require('../models/reservation');
var User = require('../models/user');
var notifier = require('../lib/notifier');
var purchaser = require('../lib/purchaser');
var middleware = require('../lib/middleware');

router.get('/', middleware.isAuthenticated, function (req, res) {
  var userId = req.user.id;
  Reservation.find({})
  .deepPopulate('property property.owner guest')
  .then(function (reservations) {
    var hostReservations = reservations.filter(function (reservation) {
      return reservation.property.owner.id === userId;
    });

    res.render('reservations/index', { reservations: hostReservations, user: req.user });
  });
});

// POST: /reservations
router.post('/', function (req, res) {
  var propertyId = req.body.propertyId;
  var user = req.user;

  Property.findOne({ _id: propertyId })
  .then(function (property) {
    var reservation = new Reservation({
      message: req.body.message,
      property: propertyId,
      guest: user.id
    });

    return reservation.save();
  })
  .then(function () {
    notifier.sendNotification();
    res.redirect('/properties');
  })
  .catch(function(err) {
    console.log(err);
  });
});

// POST: /reservations/handle
router.post('/handle', twilio.webhook({validate: false}), function (req, res) {
  var from = req.body.From;
  var smsRequest = req.body.Body;

  var smsResponse;

  User.findOne({phoneNumber: from})
    .then(function (host) {
      return Reservation.findOne({status: 'pending'})
        .deepPopulate('property property.owner guest')
    })
    .then(function (reservation) {
      if (reservation === null) {
        throw 'No pending reservations';
      }

      var hostAreaCode = reservation.property.owner.areaCode;

      var phoneNumber = purchaser.purchase(hostAreaCode);
      var reservationPromise = Promise.resolve(reservation);

      return Promise.all([phoneNumber, reservationPromise]);
    })
    .then(function (data) {
      var phoneNumber = data[0];
      var reservation = data[1];

      if (isSmsRequestAccepted(smsRequest)) {
        reservation.status = "confirmed";
        reservation.phoneNumber = phoneNumber;
      } else {
        reservation.status = "rejected";
      }
      return reservation.save();
    })
    .then(function (reservation) {
      var message = "You have successfully " + reservation.status + " the reservation";
      respond(res, message);
    })
    .catch(function (err) {
      console.log(err);
      var message = "Sorry, it looks like you do not have any reservations to respond to";
      respond(res, message);
    });
});

var isSmsRequestAccepted = function (smsRequest) {
  return smsRequest.toLowerCase() === 'accept';
};

var respond = function(res, message) {
  var messagingResponse = new MessagingResponse();
  messagingResponse.message(message);

  res.type('text/xml');
  res.send(messagingResponse.toString());
}

module.exports = router;
```

Part of our reservation system is receiving reservation requests from potential renters. However, these reservations need to be confirmed. Let's see how we would handle this step.

## Confirm the Reservation

Before the reservation is finalized, the host needs to confirm that the property was reserved. Learn how to automate this process in our first AirTNG tutorial, [Workflow Automation](https://github.com/TwilioDevEd/airtng-node).

```js title="Confirm the Reservation" description="routes/reservations.js"
// !mark(49:94)
var twilio = require('twilio');
var MessagingResponse = require('twilio').twiml.MessagingResponse;
var express = require('express');
var router = express.Router();
var Property = require('../models/property');
var Reservation = require('../models/reservation');
var User = require('../models/user');
var notifier = require('../lib/notifier');
var purchaser = require('../lib/purchaser');
var middleware = require('../lib/middleware');

router.get('/', middleware.isAuthenticated, function (req, res) {
  var userId = req.user.id;
  Reservation.find({})
  .deepPopulate('property property.owner guest')
  .then(function (reservations) {
    var hostReservations = reservations.filter(function (reservation) {
      return reservation.property.owner.id === userId;
    });

    res.render('reservations/index', { reservations: hostReservations, user: req.user });
  });
});

// POST: /reservations
router.post('/', function (req, res) {
  var propertyId = req.body.propertyId;
  var user = req.user;

  Property.findOne({ _id: propertyId })
  .then(function (property) {
    var reservation = new Reservation({
      message: req.body.message,
      property: propertyId,
      guest: user.id
    });

    return reservation.save();
  })
  .then(function () {
    notifier.sendNotification();
    res.redirect('/properties');
  })
  .catch(function(err) {
    console.log(err);
  });
});

// POST: /reservations/handle
router.post('/handle', twilio.webhook({validate: false}), function (req, res) {
  var from = req.body.From;
  var smsRequest = req.body.Body;

  var smsResponse;

  User.findOne({phoneNumber: from})
    .then(function (host) {
      return Reservation.findOne({status: 'pending'})
        .deepPopulate('property property.owner guest')
    })
    .then(function (reservation) {
      if (reservation === null) {
        throw 'No pending reservations';
      }

      var hostAreaCode = reservation.property.owner.areaCode;

      var phoneNumber = purchaser.purchase(hostAreaCode);
      var reservationPromise = Promise.resolve(reservation);

      return Promise.all([phoneNumber, reservationPromise]);
    })
    .then(function (data) {
      var phoneNumber = data[0];
      var reservation = data[1];

      if (isSmsRequestAccepted(smsRequest)) {
        reservation.status = "confirmed";
        reservation.phoneNumber = phoneNumber;
      } else {
        reservation.status = "rejected";
      }
      return reservation.save();
    })
    .then(function (reservation) {
      var message = "You have successfully " + reservation.status + " the reservation";
      respond(res, message);
    })
    .catch(function (err) {
      console.log(err);
      var message = "Sorry, it looks like you do not have any reservations to respond to";
      respond(res, message);
    });
});

var isSmsRequestAccepted = function (smsRequest) {
  return smsRequest.toLowerCase() === 'accept';
};

var respond = function(res, message) {
  var messagingResponse = new MessagingResponse();
  messagingResponse.message(message);

  res.type('text/xml');
  res.send(messagingResponse.toString());
}

module.exports = router;
```

Once the reservation is confirmed, we need to purchase a Twilio number that the guest and host can use to communicate.

## Purchase a Twilio Number

Here we use a [Twilio Node SDK](https://github.com/twilio/twilio-node) to search for and buy a new phone number to associate with the reservation. When we buy the number, we designate a [Twilio Application](/docs/usage/api/applications) that will handle [webhook](https://en.wikipedia.org/wiki/Webhook) requests when the new number receives an incoming call or text.

We then save the new phone number on our `reservation` model, so when our app receives calls or texts to this number, we'll know which reservation the call or text belongs to.

```js title="Purchase a Twilio Number" description="lib/purchaser.js"
var config = require('../config');
var client = require('twilio')(config.accountSid, config.authToken);

var purchase = function (areaCode) {
  var phoneNumber;

  return client.availablePhoneNumbers('US').local.list({
        areaCode: areaCode,
        voiceEnabled: true,
        smsEnabled: true
  }).then(function(searchResults) {
    if (searchResults.availablePhoneNumbers.length === 0) {
      throw { message: 'No numbers found with that area code' };
    }

    return client.incomingPhoneNumbers.create({
      phoneNumber: searchResults.availablePhoneNumbers[0].phoneNumber,
      voiceApplicationSid: config.applicationSid,
      smsApplicationSid: config.applicationSid
    });
  }).then(function(number) {
    return number.phone_number;
  });
}

exports.purchase = purchase;
```

Now that each reservation has a Twilio Phone Number, we can see how the application will look up reservations as guest or host calls come in.

## Find a Reservation

When someone sends an SMS or calls one of the Twilio numbers you have configured, Twilio makes a request to the URL you set in the TwiML app. In this request, Twilio includes some useful information including:

* The `From` number that originally called or sent an SMS.
* The `To` Twilio number that triggered this request.

Take a look at [Twilio's SMS Documentation](/docs/messaging/twiml) and [Twilio's Voice Documentation](/docs/voice/twiml) for a full list of the parameters you can use.

In our controller we use the `to` parameter sent by Twilio to find a reservation that has the number we bought stored in it, as this is the number both hosts and guests will call and send SMS to.

```js title="Find a Reservation" description="routes/commuter.js"
// !mark(41:65)
var twilio = require('twilio');
var VoiceResponse = require('twilio').twiml.VoiceResponse;
var MessagingResponse = require('twilio').twiml.MessagingResponse;
var express = require('express');
var router = express.Router();
var Reservation = require('../models/reservation');

// POST: /commuter/use-sms
router.post('/use-sms', twilio.webhook({ validate: false }), function (req, res) {
  from = req.body.From;
  to   = req.body.To;
  body = req.body.Body;

  gatherOutgoingNumber(from, to)
  .then(function (outgoingPhoneNumber) {
    var messagingResponse = new MessagingResponse();
    messagingResponse.message({ to: outgoingPhoneNumber }, body);

    res.type('text/xml');
    res.send(messagingResponse.toString());
  })
});

// POST: /commuter/use-voice
router.post('/use-voice', twilio.webhook({ validate: false }), function (req, res) {
  from = req.body.From;
  to   = req.body.To;
  body = req.body.Body;

  gatherOutgoingNumber(from, to)
  .then(function (outgoingPhoneNumber) {
    var voiceResponse = new VoiceResponse();
    voiceResponse.play('http://howtodocs.s3.amazonaws.com/howdy-tng.mp3');
    voiceResponse.dial(outgoingPhoneNumber);

    res.type('text/xml');
    res.send(voiceResponse.toString());
  })
});

var gatherOutgoingNumber = function (incomingPhoneNumber, anonymousPhoneNumber) {
  var phoneNumber = anonymousPhoneNumber;

  return Reservation.findOne({ phoneNumber: phoneNumber })
  .deepPopulate('property property.owner guest')
  .then(function (reservation) {
    var hostPhoneNumber = formattedPhoneNumber(reservation.property.owner);
    var guestPhoneNumber = formattedPhoneNumber(reservation.guest);

    // Connect from Guest to Host
    if (guestPhoneNumber === incomingPhoneNumber) {
      outgoingPhoneNumber = hostPhoneNumber;
    }

    // Connect from Host to Guest
    if (hostPhoneNumber === incomingPhoneNumber) {
      outgoingPhoneNumber = guestPhoneNumber;
    }

    return outgoingPhoneNumber;
  })
  .catch(function (err) {
    console.log(err);
  });
}

var formattedPhoneNumber = function(user) {
  return "+" + user.countryCode + user.areaCode + user.phoneNumber;
};

module.exports = router;
```

Next, let's see how to connect the guest and the host via SMS.

## Connect Via SMS

Our [Twilio application](/docs/usage/api/applications) should be configured to [send HTTP requests](/docs/voice/twiml) to this controller method on any incoming text message. Our app responds with [TwiML](/docs/voice/twiml) to tell Twilio what to do in response to the message.

If the initial message sent to the anonymous number was sent by the host, we forward it on to the guest. Conversely, if the original message was sent by the guest, we forward it to the host.

*To find the outgoing number we'll use the `gatherOutgoingNumber` helper method.*

```js title="Connect Via SMS" description="routes/commuter.js"
// !mark(8:22)
var twilio = require('twilio');
var VoiceResponse = require('twilio').twiml.VoiceResponse;
var MessagingResponse = require('twilio').twiml.MessagingResponse;
var express = require('express');
var router = express.Router();
var Reservation = require('../models/reservation');

// POST: /commuter/use-sms
router.post('/use-sms', twilio.webhook({ validate: false }), function (req, res) {
  from = req.body.From;
  to   = req.body.To;
  body = req.body.Body;

  gatherOutgoingNumber(from, to)
  .then(function (outgoingPhoneNumber) {
    var messagingResponse = new MessagingResponse();
    messagingResponse.message({ to: outgoingPhoneNumber }, body);

    res.type('text/xml');
    res.send(messagingResponse.toString());
  })
});

// POST: /commuter/use-voice
router.post('/use-voice', twilio.webhook({ validate: false }), function (req, res) {
  from = req.body.From;
  to   = req.body.To;
  body = req.body.Body;

  gatherOutgoingNumber(from, to)
  .then(function (outgoingPhoneNumber) {
    var voiceResponse = new VoiceResponse();
    voiceResponse.play('http://howtodocs.s3.amazonaws.com/howdy-tng.mp3');
    voiceResponse.dial(outgoingPhoneNumber);

    res.type('text/xml');
    res.send(voiceResponse.toString());
  })
});

var gatherOutgoingNumber = function (incomingPhoneNumber, anonymousPhoneNumber) {
  var phoneNumber = anonymousPhoneNumber;

  return Reservation.findOne({ phoneNumber: phoneNumber })
  .deepPopulate('property property.owner guest')
  .then(function (reservation) {
    var hostPhoneNumber = formattedPhoneNumber(reservation.property.owner);
    var guestPhoneNumber = formattedPhoneNumber(reservation.guest);

    // Connect from Guest to Host
    if (guestPhoneNumber === incomingPhoneNumber) {
      outgoingPhoneNumber = hostPhoneNumber;
    }

    // Connect from Host to Guest
    if (hostPhoneNumber === incomingPhoneNumber) {
      outgoingPhoneNumber = guestPhoneNumber;
    }

    return outgoingPhoneNumber;
  })
  .catch(function (err) {
    console.log(err);
  });
}

var formattedPhoneNumber = function(user) {
  return "+" + user.countryCode + user.areaCode + user.phoneNumber;
};

module.exports = router;
```

Let's see how to connect the guest and the host via phone call next.

That's it! We've just implemented anonymous communications that allow your customers to connect while protecting their privacy.

## Where to Next?

If you're a Node.js developer working with Twilio, you might want to check out these other tutorials:

[**IVR: Phone Tree**](/docs/voice/tutorials/build-interactive-voice-response-ivr-phone-tree/node)

You can route callers to the right people and information with an IVR (interactive voice response) system.

[**Automated Survey**](/blog/automated-survey-nodejs-express)

Instantly collect structured data from your users with a survey conducted over a voice call or SMS text messages. Learn how to create your own survey in the language and framework of your choice.

### Did this help?

Thanks for checking out this tutorial! If you have any feedback to share with us, we'd love to hear it. Tweet [@twilio](http://twitter.com/twilio) to let us know what you think.