Create an Alexa skill in Node.Js and host it on Heroku

Ok, here we go.

So for the last couple weeks I’ve been totally enamored with working with Alexa. It’s really fun to have a programming project that can actually ‘interact’ with the real world. Until now I’ve just been using my hacked together web server with If This Then That commands to trigger events. After posting some of my work on Reddit, I got some encouragement to try and develop and actual Alexa skill, instead of having to piggyback off IFTTT. With some sample code, an awesome guy willing to help a bit along the way and more than a little caffeine I decided to give it a shot.

The Approach: Since I already have a decent handle on Node.Js and I was informed there are libraries for working with Alexa, I decided Node would be my language of choice for accomplishing this. I’ll be using alexa-app-server and alexa-app Node.Js libraries. I’ll be using 2 github repos, and hosting the end result on Heroku.

How it’s done: I’ll be honest, this is a reasonably complex project with about a million steps, so I’ll do my best to outline them all but forgive me if I gloss over a few things. We will be hosting our server in github, creating a repo for the server, making a sub module for the skill, and deploying it all to Heroku. Lets get started. First off, go and get yourself a github account and a Heroku account. If you haven’t used git yet, get that installed. Also install the heroku toolbelt (which may come with git, I can’t quite remember). Of course you’ll also need node.js and Node Package Manager (NPM) which odds are you already have.

If you don’t want to create all the code and such from scratch and want to just start with a functioning app, feel free to clone my test app https://github.com/Kenji776/AlexaServer1.git

Create a new directory for your project on your local machine for your project. Then head on over to github and create yourself a new project/repo. Call it AlexaServer or something similar. Go ahead and make it a public repo. Do not initialize it with a readme at this time. This is the repo where the core server code will live. It’s important to think of the server code as a separate component from each individual skill, they are distinct things. You should see this screen.

Open a command prompt and change to the directory you created for your project. Enter the commands show in the first section for creating a new repository. Once those commands are entered if you refresh the screen you shoud see your readme file there with the contents shown like this.

Okay, now we are ready to get the Alexa-Server app, https://www.npmjs.com/package/alexa-app-server is what you are looking for. In your project directory type in

“npm install alexa-app-server”

This will take a few moments but should complete without any problems. In your project folder you’ll want to create a folder called apps. This is where each individual skill will live. We will cover that later. Now you’ll need to create your actual server file. Create a file called server.js. Put this in there.

'use strict' ; var AlexaAppServer = require( 'alexa-app-server' ); var server = new AlexaAppServer( { httpsEnabled: false , port: process.env.PORT || 80 } ); server.start();

Pretty simple code overall. The weird bit of code in the port section is for Heroku (they give your app a port to use when hosted). If not on Heroku then it will default to using port 80. Now you need to create your Procfile. This is going to tell Heroku what to do when it tries to run your program. It should be a file named Procfile in the same directory with no file extension. The contents of which are simply

“web: node server.js”

without quotes. We will also want to create a package.json file. So again in your project directory run the command

npm init

This will run a script and it will ask you a few questions. Answer them and your package.json file should get generated. Go ahead and push this all into Github using the following command sequence.

git add .

git commit -m “added server.js and Procfile, along with alexa-app-server-dependency”

git push origin master

If you view your Github repo online you should see all your files there. It should look something like this.

You can see all of our files got pushed in. Now with the server setup, it’s time to create our skill. Create another GitHub repo. Call this whatever you like, hopefully something descriptive of the skill you are making. In your command prompt get into the apps directory within your main project. In there create another folder with a name same or similar to your new GitHub repo. Follow the same steps as before to initialize the repo and do the initial commit/push. Now we are going to indicate to GitHub that the apps/test-skill folder is actually a sub module so any dependencies and such will be maintained within itself and not within the project root. To do this navigate to the root project folder and enter.

git submodule add https://github.com/Kenji776/AlexaTestSkill.git apps/test-skill

Replacing the github project url with the one for your skill, and the apps/test-skill with apps/whatever-your-skill-is-named. Now Git knows that this folder is a submodule, but NPM doesn’t know that. If you try and install anything using NPM for this skill it’s going to toss it into the root directory of the project. So we generate a package.json file for this skill and then NPM knows that this skill is a stand alone thing. So run

npm init

Again and go through all the questions again. This should generate a package.json file for your skill. Now we are ready to install the actual alexa-app package. So run…

npm install alexa-app –save

and you should see that the skill now has it’s own node_modules folder, in which is contained the alexa-app dependency. After this you’ll have to regenerate your package.json file again because you’ve now added a new dependency. Now it’s time to make our skill DO something. In your skill folder create a file called index.js. Just to get started as a ‘hello world’ kind of app, plug this into that file.

module.change_code = 1 ; 'use strict' ; var alexa = require( 'alexa-app' ); var app = new alexa.app( 'test-skill' ); app.launch( function ( request, response ) { response.say( 'Welcome to your test skill' ).reprompt( 'Way to go. You got it to run. Bad ass.' ).shouldEndSession( false ); } ); app.error = function ( exception, request, response ) { console.log(exception) console.log(request); console.log(response); response.say( 'Sorry an error occured ' + error.message); }; app.intent( 'sayNumber' , { "slots" :{ "number" : "NUMBER" } , "utterances" :[ "say the number {1-100|number}" , "give me the number {1-100|number}" , "tell me the number {1-100|number}" , "I want to hear you say the number {1-100|number}" ] }, function (request,response) { var number = request.slot( 'number' ); response.say( "You asked for the number " +number); } ); module.exports = app;

Now, if you aren’t familiar with how Alexa works, I’ll try and break it down for you real quick to explain what’s happening with this code. Every action a skill can perform is called an intent. It is called this because ideally there are many ways a person might trigger that function. The might say “say the number {number}” or they might say “give me the number {number}” or many other variations, but they all have the same intent. So hence the name. Your intent should account for most of the common ways a user a might try to invoke your functions. You do this by creating utterances. Each utterance represents something a user might say to make that function run. Slots are variables. You define the potential variables using slots, then use them in your utterances. There are different types of data a slot can contain, or you can create your own. Check out https://developer.amazon.com/public/solutions/alexa/alexa-skills-kit/docs/alexa-skills-kit-interaction-model-reference for more information on slots types. I’m still figuring them out myself a bit. So the intent is triggered by saying one of the utterances. The slot is populated with the number the person says, and after reading the variable from the request, it is read back to the user.

So now, believe it or not, your skill is usable. You can test it by heading by starting your server. Again in your command line shell within the root project directory type

node server.js

A console window should show up that looks like this.

Now in your browser you should be able to bring up an emulator/debugger page be heading to

http://yourserver/alexa/your-skill-name (EX: http://localhost/alexa/test-skill)

You should get a page that looks like this.

Holy cow, we did it! We have a functioning skill. The only problem now is that there is no way for Alexa to ‘get to it’. As in, Alexa doesn’t know about this skill, so there is no way for echo to route requests to it (also, I find it mildly creepy that when referring to Alexa, I keep accidentally wanting to type ‘her’. Ugh). So now we have to put this skill somewhere were it’s accessible. That is where Heroku is going to come in. Sure we could host this on our local machine, setup port forwarding, handle the SSL certs ourselves, but who wants to have their skill always running on their local box? I’ll do a bit on how to do that later since it requires creating a self signed SSL certificate using openSSL and such but for now I’m going to focus on getting this sucker into a cloud host.

Oh by the way, once everything is working smoothly, you should commit and push it all into github. Remember, you’ll have to do a separate commit and push for your server, and for the skill submodule since they are officially different things as far as github is concerned, even though the skill is a sub directory of your server. Also, I’m still learning exactly how submodules work, but if for some reason it doesn’t seem like your submodule is updating properly you can navigate to the project root folder and try this series of commands.

git submodule foreach git pull origin master

git add .

git commit -m “updated submodule”

git push origin master

with some luck that should do it. You’ll know it’s all working right when you open up your server repo in github, click the apps folder and you see a greyish folder icon for the name of your skill. Clicking it should show you the skill with all the files in there. Like this.

Now, on to Heroku. This part is pretty easy comparatively. Head on over to Heroku and create a new app. As usual, name it whatever you like, preferably something descriptive. Next you’ll be in the deploy area. You’ll be able to specify where the code comes from. Since we are smart, and we used github you can actually just link this heroku project straight to your github project.



Just like that! However, this automatic integration does not seem to include sub modules, so we will have to add our skill submodule from the command line. So again navigate to your project folder from the shell, and run this command to link your directory with the heroku project.

heroku git:remote -a alexatestapp

Of course replacing alexatestapp with whatever the name of your heroku app is. You should get back a response saying that the heroku remote has been added. Now we need to push it all into Heroku (which in retrospect may have made the above linking done from the website un-needed, but whatever. It doesn’t seem to hurt anything). So now run

git push heroku master

You should be treated with a whole bunch of console output about compressing, creating runtimes, resolving dependencies, blah blah blah. Now with some luck your app should work via your hosted Heroku app. Just like when hosted locally we can access the emulator/debugger by going to

https://alexatestapp.herokuapp.com/alexa/test-skill

Replacing the domain with your heroku app, and the skill with whatever your skill is named. If all has gone well it should operate just like it did on your local machine. We are now finally ready to let Amazon and Echo know about our new skill. So head on over to https://developer.amazon.com/edw/home.html#/skills/list (you’ll need to sign up for a developer account if you do not have one) and click the add new skill button.

On the next page it’s going to ask you for your intent schema. This is just a JSON representation of your intents and their slots. Thankfully that handy debug page generates that for you. So it’s just copy paste the intent schema from the debug page into that box. It will ask you about custom slot types, and odds are if you are making a more complicated app you are going to want to make your own, but really all that is is creating a name for your data type, common values for it (no it doesn’t have to be every value) and saving it. Spend some time reading the docs on custom slot types if you need to. It’s also going to want sample utterances, which again that debug page generates for you, so again, just copy paste. You might get a few odd errors here about formatting, or wrong slot types. Just do your best to work through them.

Next up is setting up the HTTPS. Thankfully Heroku handles that for us, so we don’t have to worry about it! Just select

“My development endpoint is a subdomain of a domain that has a wildcard certificate from a certificate authority”

Next up us account linking. I haven’t figured that one out yet, still working on it, so for now we just have to say no. Next up is the test screen. If everything is gone well up to this point, it should work just peachy for ya.

Next you’ll be asked to input some meta data about your app. Description, keywords, logo, icon, etc. Just fill it out and hit next. Finally you’ll be asked about privacy info. For now you have just say no to everything, and come back to update that when you’ve got your million dollar app ready to go. Hit save and you should be just about ready to test through your Echo. If you open your Alexa app on your phone and look for your skill by name, you should find it and it should be automatically enabled. You should now be able to go to your echo, use the wake word, speak the invocation name and ask for a number. If all has gone well you’ll hear the wonderful sound of Alexa reading back your number to you. For example

“Alexa Ask Test Get My Number”

Alexa should respond with what you defined as the app start message in your skill. You can now say

“Say the number 10”

Which should then be repeated back to you. Congrats. You just created a cloud hosted, Node.Js Alexa Skill that is now ready for you to make do something awesome. Get out there and blow my mind. Good luck!