#ruby Jul 24th, 2022

Building Easter Eggs Into Phone Systems With Ruby

Cody Norman

What started as just a note for something to look into when I was between tasks and has turned into something that’s been a blast to work with.

I don’t know why I’ve been so fascinated with easter eggs has been lately.

Maybe because an easter egg is something like a secret way to identify members of your tribe. Something that easily gets passed by or ignored by most people, but really strikes a note for people that get it. Kind of like a digital inside joke, but one that doesn’t exclude or leave anyone out.

For me, I think it’s also a good representation of Ruby

It’s a little weird, quirky, focuses on developer happiness, and can easily be useful or just for fun.

This whole experience has been a lot of fun for me. You may see me repeating that phrase fun for me and might not think much of it, but for me, it’s been a reinvention.

I don’t think I realized how much I wasn’t enjoying development for the past couple of years. I wasn’t motivated to do much more than just get by. It really felt like treading water. There’s also nothing wrong with just getting by and doing your work. In the tech bubble, it can seem like everyone everywhere is working non-stop. But nobody can judge how you’re feeling better than you so don’t feel like you’re somehow obligated to code in all your free time or publish blog posts constantly. Go at your own pace and do what feels right.

The past year or so, I’ve had some ideas for things I wanted to work on that are some Hell Yeah ideas. After blocking out some dedicated time each day for work only on side projects, I was able to get to my ever elusive MIP

That’s my Minimum Interesting Product. The point where your project gets over the hump of boilerplate, setup and adding some basic styles and gets to a point where you can focus on specific features.

That’s something I started using to describe the inflection point on a project where I keep coming back to it because all the boring stuff is done. I don’t believe that’s something like a recognized term so you might get some weird looks if you throw that out around other people. If they ask for more information, tell them you made it up and begin your journey as a thought leader. I’ll back you up.

SaaS templates and frameworks like Bullet Train and Jumpstart have made that process a lot easier and let you get to the good stuff. I’ve used both in the past and allowed me to get right to the fun stuff.

Anyway, having some non-trivial projects for the first time in a long time really sharpened my skills and more importantly, got my wheels turning again in a way they haven’t in some time.

One of the things I wanted to add to this project was working in an easter egg somewhere. I wasn’t sure where, or what it would be, I just had a note about how I thought it would be fun to work in if something ever came up.

Well, it came up.

I was working with a Twilio programmable phone number sending and receiving SMS messages and alerts. I’ve worked with SMS a ton in the past, but I don’t think I’ve ever called one of the numbers. So I decided to call and see what would happen.

I got a voice response from Twilo about how I needed to configure a way to handle the calls. After a little research, I saw it was really similar to how SMS is handled. When Twilio gets an inbound SMS or Phone call, a request is sent to your defined webhooks URL.

The main difference from the SMS webhooks is you need to send a TwiML response to the webhook request. TwiML is basically Twilio flavored XML to control voice interactions.

I found a few examples of the capabilities and thought I could get a response working without too much hassle. I added something pretty close to their docs to respond with a simple message saying this number was for inbound messages only and email support at blah blah blah dot com

Instead of constructing the XML on my own, the twilio-ruby gem has support for creating the reqiured TwiML responses.

Outside of creating a new endpoint for the voice webhook, I was able to get a response working with a few lines of code

If you want to test this out locally, you’ll need something like ngrok to point the webooks to your local machine. It can be a bit tedious keeping those updated so I created a post on creating a rake take to automatically set your twilio webhook routes for voice and SMS with a rake task here

def parse
  response = Twilio::TwiML::VoiceResponse.new do |r|
    r.say(message: 'I wish I had a cool robot voice')

  render xml: response.to_xml

I’ve mentioned before how much I love using established technology like SMS and email. With just a few lines, I was able to add voice to the mix.

I started looking through some of the examples and docs and found some really cool capabilities and options.

One of the options was different voices with Amazon Polly in addition to the Twilio voices. I remember thinking something along the lines of “I wish there was a cool 80s robot-sounding voice like the computer from War Games” What’s War Games?

Alas, there was not.

However… I did remember seeing an example of returning the URL of an MP3 file that would play on the call.

That got me thinking…. maybe I could fake my own Joshua computer voice with some sound clips. Of course, “Would you like to play a game” is what I always think about when I hear War Games.

That phrase got me thinking about the move and playing games with the computer. After all, he does connect with the super-computer by dialing a phone line.

All of a sudden, I had an idea for my easter egg. With some searching, I found the phone number his modem dialed into to connect to the computer and thought that would be the perfect thing to start the sequence.

TwiML has the option to gather responses by either pressing buttons on touch-tone phone (do people still say that, am I dating myself?) or speech.

For the response, I created a gather block around my existing phone message. That allowed me to collect user input, without making it apparent to the caller

The gather block needs a route to redirect to. That takes input from your phone call along with some other information and sends a webhook request with the corresponding data to that route.

The params for that request include Digits. That’s all I needed to check the input against a condition. In this case, I was looking for the phone number to the computer from the movie. 3992364

  def parse
    response = Twilio::TwiML::VoiceResponse.new
    response.gather(action: webhooks_parse_voice_input_path) do |g|
      g.say(message: "This number is for outbound messages only.  Please email something@blah blah blah.com for assistance")
    # webhooks_parse_voice_input_path is another endpoint that needs to be created
    render xml: response.to_xml

For this block, the breakdown is:

  • Create a new response
  • Start gathering input from the user
  • Read the message saying this number is for outbound messages only and to email support with issues
  • Set the route to redirect to after this request finishes
  • Render XML response

In the example above, it’s always going to send a request to the redirect webhook endpoint. My thinking was that anyone not trying to poke around would have hung up by now. If you would like more control over the call flow, you can hang up the call with response.hangup

In the next endpoint, we start checking the inputs from the user. There are options for both speech and digit input but for now, it’s just focusing on the digit input.

After entering the secret code, things start to get interesting.

  def parse_voice_input
    if params["Digits"] && params["Digits"] == "3992364"
      response = Twilio::TwiML::VoiceResponse.new do |r|
        r.gather(input: "speech", action: webhooks_parse_easter_egg_response_path) do |g|
          g.play(url: "https://s3.us-east-2.amazonaws.com/Greetings.mp3")
          g.play(url: "https://s3.us-east-2.amazonaws.com/Its+been+long+time.mp3")
          g.play(url: "https://s3.us-east-2.amazonaws.com/Play+a+game.mp3")
    render xml: response.to_xml

I mentioned before I thought about hacking together my own Joshua voice (80s computer voice) by stringing together a few voice clips. 3 to be exact. I found some clips that would work and uploaded them to an S3 bucket. The quality is not great, but I’m thankful someone took the time to put those together and make them free to download.

Together, the prompts are something like this:

“Greetings professor Falken”

“It’s been a long time, can you explain the removal of your user account…”

“Shall we play a game?”

These clips are also wrapped in a gather block. So we’re accepting input and will redirect to another endpoint as a handler.

After that starts, there are 3 possible outcomes.

  • Input we’re checking for
  • Input we’re not checking for
  • Caller doing nothing

Let’s start with the do nothing option (the else condition)

If you don’t do anything after hearing the response, you hit the fallback option that returns a cheeky response:

‘Strange game, the only winning move is not to play’

This was the climax of the movie after he teaches it to play tic-tac-toe against itself and realizes there are no winning moves in thermonuculear war.

  def parse_easter_egg_response
    response = if params["Digits"] == "567482"
      Twilio::TwiML::VoiceResponse.new do |r|
        r.say(message: "You have chosen wisely, email global thermonuclear war@blah blah blah.com to claim your prize. Goodbye")
    elsif params["Digits"] == "325536"
      Twilio::TwiML::VoiceResponse.new do |r|
        r.say(message: "You have chosen wisely, email global thermonuclear war@blah blah blah.com to claim your prize. Goodbye")
      Twilio::TwiML::VoiceResponse.new do |r|
        r.play(url: "https://s3.us-east-2.amazonaws.com/strange-game-the-only-winning-move-is-not-to-play.mp3")
    render xml: response.to_xml

The other two options rely on user input.

The two successful responses are entering numberic representation of ‘Joshua’ (567482) and ‘Falken’ (325536). Professor Falken was the creator of the program and Joshua was the name of his son who died and the secret logon to gain access.

With the code block above, there’s no difference in the response, I just wanted to have a couple of different options for success.

Entering either of the secret codes correctly plays a message with an email address to email to claim a gift.

That’s pretty much it. This is a goofy, and hopefully fun, example showing some power concepts.

  • Creating speech from text as a response to a caller
  • Playing Mp3 files
  • Handling and parsing user input and speech”

Pretty neat, right? I thought so. After starting on the first version of this post, I had another idea for a goofy and fun thing to build that I couldn’t seem to shake so decided to take some time and build it.

I’ll have another post that goes into that idea in more detail soon.