Horea's Blog

Demo of the finished product:

In this blog post, i’ll go over how to use IBM’s Function-as-a-Service (Faas), OpenWhisk, to build a basic translation app. Our app will get its data by using REST API calls to talk to Watson. Keep in mind that you could use any sort of back end written in any langauge you want, but I chose OpenWhisk since I wanted to get familiar working with a Function-as-a-Service. This exercise is great for developers that are interested in learning REST API and implementing something quickly that they could then put on their resume. The goal of this post is to help you understand REST API calls and Function-as-a-Service back end services. To get started, you must have:

  • a free IBM Cloud ‘Bluemix’ account from here

  • the OpenWhisk CLI (also free) downloaded and ready to go, from here

The code explained in this blog is available here on Github. If you are not familiar with OpenWhisk, or Function-as-a-Service, you can read a bit more about it here. Unsurprisingly, it took me some time to wrap my head around, but I do think it is a really powerful tool for developers, and could save you a lot of money down the road if used properly. It’s not ideal for every use case, but for some use cases it works extremely well. Enough about that, let’s get started.

Your First Web Action

First and foremost let’s create an empty directory called OpenWhisk. We will keep all of the files for the project in this directory. Next, let’s create a new file called hello.js and paste this code in your editor.

function main({name}) {
  var msg = 'you did not tell me who you are.';
  if (name) {
    msg = `hello ${name}!`
  return {body: `<html><body><h3>${msg}</h3></body></html>`}

Go to the directory where your file is, and run this command to create a package where your web action can live.

wsk package create demo1

Note: If this command failed, go back up to the first step where you downloaded the OpenWhisk CLI and test it again to make sure it works.

Now, in the same directory run this command to enable your action to be a web action.

wsk action create demo1/hello hello.js --web true

If everything worked, you should see something like this:

Mountain View

Note: I had already created a package called “demo1”, so I had to create a package called “demo14”. It’s the same thing, and for the purpose of this demo, stick to calling your package “demo1”.

By running this command, you will be able to access your action through a unique URL without authentication. Be careful!

Finding your Web Action URL

This step took me a while to get. Your Web Action URL is essentially:

https://{APIHOST}/api/v1/web/{QUALIFIED ACTION NAME}.{EXT}

If you are using Bluemix, the APIHOST is:


To see your Qualified Action Name, simply type this in:

wsk action list

You should see something like this…yes, I scratched out part of mine :)

Mountain View

This part is really really important, so pay attention. Check to see what your namespace is. Mine is “_dev”. Now, using my example, and taking the first action, the web URL is:


P.S. don’t try to go to the above URL, it won’t do anything. Next, let’s pass in a query parameter. Your URL should look similar to mine above, except for your own particular namespace.


Open the URL above (adjusted for your particular namespace) and you should see something like this on your screen. If you don’t see this, you most likely messed up on the URL. If you want to read more about web actions, check out the documentation.

Mountain View

Cool! Now that you have a basic understanding of how web actions work with OpenWhisk, let’s start a more interesting example.

Building a Backend With OpenWhisk

Open up a new file called test.js, and paste the following code:

var request = require('request');

function main(params) {
  //Language Translation Service Credentials
  var username = "username";
  var password = "password";

  var postURL = "https://" + username + ":" + password +

  var promise = new Promise(function(resolve, reject) {
      url:     postURL,
      //the inputs to make the call to Language Translation
      json: {
        'source' : params.source,
        'target' : params.target,
        'text' : params.text
    function(error, response, body){
      resolve ({
        //need to return this so that HTTP Response body is parsed correctly
        headers: {
          'content-type': 'application/json'
        body: new Buffer (body.translations[0].translation).toString('base64')
  return promise;

After copy and pasting, change the username and password variables with your Watson Translation Service Credentials. To find your Credentials, go to your Bluemix Dashboard, click on “Create Service”, -> Language Translator -> Create. Then back on your dashboard, go to your service, click on “Language Translator-4d” -> Service Credentials -> View Credentials.

What we are doing above is making a HTTP Post request to the Watson Platform to be able to use their Language Translation. We will pass in the source langauge, target language, and the text to translate through our front end (which we will build right after this section!) and Watson will do all the back end work. One tricky part is that we have to return our content-type headers as well as create a buffer so that our app can parse the body of the HTTP Response correctly.

Now let’s make this a web action. Make sure you are in the same directory where test.js is, save the file, and type the following in your command line:

wsk action create demo1/test test.js --web true

Let’s test this out. Open up the following URL in your browser(again fill in your personal namespace as we learned above):


If all went well, you should see the following in your browser:

Mountain View

If you do not see this, check your URL and make sure you are putting in your correct namespace. Everything should be very similar to the hello example above. The only difference is that we made a different action based on a different file.

Building a Web Front End

Next, I’m going to show you how to create a simple front end using JavaScript. First create a index.html file in the same folder as your test.js file, and then copy and paste the following code in your index.html

<!--Created by Horea Porutiu-->
    <link rel="stylesheet" href="style.css">
    <div id = "background">
      <center><h1>Watson Translate</h1></center>
      <div id="left">
        <center><label id="leftLabel">Input</label></center>
        <select onchange="langTest()" id="source" name="inputLang">
          <option value="English">English</option>
          <option value="Spanish">Spanish</option>
          <option value="Arabic">Arabic</option>
          <option value="Portuguese">Portuguese</option>
          <option value="French">French</option>
      <div id="right">
        <center><label id="rightLabel">Output</label></center>
        <select id="target" name="outputLang">
          <option value="Spanish">Spanish</option>
          <option value="English">English</option>
          <option value="Arabic">Arabic</option>
          <option value="Portuguese">Portuguese</option>
          <option value="French">French</option>
          <label for="text"></label>
          <input type = "text" placeholder="Translate Something..." id= "text" name="text" required>
          <form name ="login-form" action=javascript:translate()>
            <input type="submit" value="Translate">
        <div id ="transText" ></div>
        <div id = "myLoader" class="loader"></div>
    <!-- Start of JavaScript -->
      var data = {};
      var loader = document.getElementById("myLoader");
      loader.hidden = true;
      var targetLang = document.getElementById("target");
      //Disable the user from picking English as output at the start of the program,
      //since English is by default the input
      targetLang.options[1].disabled = true;

      //This function modifies Watson language translation options based on what user picks.
      //Watson can only do certain domains.
      function langTest() {
        var sourceLang = document.getElementById("source").value;
        for (i = 0; i < targetLang.options.length; ++i) {
          targetLang.value = "English";
          targetLang.options[i].disabled = false;
        if (sourceLang != "English") {
          for (i = 0; i < targetLang.options.length; ++i) {
            targetLang.value = "English";
            //diable all options since Watson tranlslates from
            //Arabic, Spanish, French and Portueguese to English only.
            if (targetLang.options[i].value != "English") {
              targetLang.options[i].disabled = true;
        //Don't let user try to translate from English to English..doesn't make sense.
        else {
          targetLang.value = "Spanish";
          targetLang.options[1].disabled = true;
      //variable that will hold our final translation
      var outputText = document.getElementById("transText");
      function translate() {
        outputText.hidden = true;
        loader.hidden = false;
        //load up our data by extracting from text field and drop down menus
        data.source = document.getElementById("source").value;
        data.target = document.getElementById("target").value;
        data.text = document.getElementById("text").value;
        //need to convert to string to be able to communicate over HTTP
        var json = JSON.stringify(data);
        var OpenWhiskUrl = "https://openwhisk.ng.bluemix.net/api/v1/web/{yournamespace}/demo1/test"
        //Our HttpRequest that will enable us to talk to Watson
        var ourRequest = new XMLHttpRequest();

        ourRequest.open("POST", OpenWhiskUrl, true);
        ourRequest.onload = function() {
          if (ourRequest.status == 400) {
            outputText.innerHTML = "Error, check your network connection.";
          else {
            //set the response from Watson to a div
            outputText.innerHTML = ourRequest.responseText;
          outputText.hidden = false;
          loader.hidden = true;

After copy and pasting, change the OpenWhiskUrl to your URL with your specific namespace. This url is the interface that will let us access our back end.

In the same directory, create a file called style.css with the following code:

body {
  background-color: #f2f2f2;
.loader {
    border: 16px solid white; /* Light grey */
    border-top: 16px solid #3498db; /* Blue */
    border-radius: 50%;
    width: 10px;
    height: 10px;
    animation: spin .5s linear infinite;
@keyframes spin {
    100% { transform: rotate(360deg); }
input[type=text], select {
    height: 50px;
    width: 50%;
    padding: 12px 20px;
    margin: 8px 0;
    display: inline-block;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-sizing: border-box;
select {
    font-size: 20px;
    width: 100%;
    height: 40px;
    padding-left: 20px;
    padding-right: 20px;
    border: none;
    border-radius: 4px;
    background-color: white;
input[type=submit] {
    width: 50%;
    background-color: #3498db;
    color: white;
    padding: 14px 20px;
    margin: 8px 0;
    border: none;
    cursor: pointer;
    font-size: 20px;
input[type=submit]:hover {
    background-color: #0CABE8;
div {
    border-radius: 5px;
    padding: 20px;
  float: right;
  float: left;
#rightLabel, #leftLabel{
  text-align: center;
#myLoader, #transText {
  position: absolute;
  margin-left: auto;
  margin-right: auto;
  left: 0;
  right: 0;
#transText {
  font-size: 30px;
label, #text{
  font-size: 20px;

Nice! Now, if you go to open your index.html file (right click, Open), you should be able to see a basic web page that looks like this:

Mountain View

If that is not what shows up for you, make sure that your index.html and style.css are in the same directory.

Watson Translate

Now that everything is setup, you should be able to test your app. Once you have opened index.html in your browser, you should be able to type in a phrase to translate.

Did you get the correct output? If so congrats! If not, please comment below and I can try to help you debug. Most likely, it’s either the credentials that were not input correctly, or the OpenWhisk URL in your index.html.

Note: Only some languages are available for translation, this is why some are blanked out when you choose certain domains.

Please give me feedback and ideas for next projects that you would like to see. Don’t be afraid to tell me this sucked! I appreciate all comments. Enjoy!

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