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Tutorial: Creating Your First Application

Prerequisite

Complete the Mojito Quickstart, which instructs you how to install Mojito and use basic commands for the Mojito command-line tool.

In this tutorial, you create a simple application that serves a single page and uses a controller to generate output.

You will learn how to do the following:

  • create an application
  • create a mojit
  • configure a mojit
  • run an action (method) on the controller
  • run unit tests for your application

Create the Application

  1. Create the Mojito application minty_app.

    $ mojito create app minty_app

  2. Change to your application directory.

    $ cd minty_app

Create the Sample Mojit

The name mojit is a fusion of the words module and widget. The mojit, however, is neither a module nor a widget. Instead, it is best understood as a unit of execution used to generate output. Mojits have an MVC structure and consist of two parts: the definition and the instance configuration.

The definition contains the controller and model code for the mojit, along with the views (and assets) used to render the output. The definition also contains unit tests for the code.

The instance configuration is what configures each instance of your mojit. For example, you might have an RSS mojit that is used to display an RSS feed. The mojit definition would have the code and views for fetching and rendering a feed, and the instance configuration would have the RSS URL to fetch, how many items to show, and whether to show thumbnails, etc.

Let’s now begin by creating your mojit, but note that you won’t be working with models or views in this tutorial.

  1. Create the mojit for your minty_app application.

    $ mojito create mojit Hello

    The Mojito command-line tool creates a canned mojit named Hello.

  2. To configure your application to use the mojit Hello, replace the code in application.json with the following:

    [
      {
        "settings": [ "master" ],
        "specs": {
          "hello": {
            "type": "Hello"
          }
        }
      }
    ]
    

    Here you have defined the instance hello of the Hello mojit, which will allow you to call the functions in the mojit controller.

  3. To set up a new route for executing your mojit, define the routing path in file app.js by adding the following above the app.listen method:

    app.get('/', libmojito.dispatch('hello.index'));
    

    This app.js file defines the routing paths, the accepted HTTP methods, and what action to take. The action is what method to call from the mojit instance when a call is made on the defined path. The app.js above configures Mojito to execute the index method from the hello instance (defined in application.json) when receiving HTTP GET calls on the root path. The app.js is also used to include middleware, set the port, and use contexts (runtime environment).

  4. From the application directory, test your application. You will notice that some tests are deferred.

    $ mojito test app .

Start the Server

  1. Start the server.

    $ node app.js

  2. Open http://localhost:8666/ in a browser.

  3. The Web page should display the following (you’ll also see documentation links and instructions for running the quickstartguide application):

    status
           Mojito is working.
    data
           some: data
    

    The text was served by the controller, the controller.server.js file in the minty_app/mojits/Hello directory. You will learn more about the controller in Modify the Sample Mojit.

  4. Stop the server by going back to your terminal pressing ^C.

Modify the Sample Mojit

You will now modify the controller, so that the index function called in the controller outputs different results.

  1. Change to mojits/Hello.

  2. Edit controller.server.js and replace the string ‘Mojito is working.’ in the code with ‘Doing well, thanks.’. Your controller.server.js should look similar to the following code:

    YUI.add('hello', function(Y, NAME) {
    
      /**
      * The hello module.
      *
      * @module hello
      **/
    
     /**
      * Constructor for the Controller class.
      *
      * @class Controller
      * @constructor
      */
      Y.namespace('mojito.controllers')[NAME] = {
    
        /**
        * Method corresponding to the 'index' action.
        *
        * @param ac {Object} The ActionContext that provides access
        *        to the Mojito API.
        **/
        index: function(ac) {
          ac.models.get('model').getData(function(err, data) {
            if (err) {
              ac.error(err);
              return;
            }
            ac.assets.addCss('./index.css');
            ac.done({
              status: 'Doing well, thanks.',
              data: data
            });
          });
        }
      };
    }, '0.0.1', {requires: [
      'mojito',
      'mojito-models-addon',
      'mojito-assets-addon'
    ]});
    

    As you can see the “controllers” are just an array of JavaScript objects, and the “action” is just a method called on the controller object. The result of the method are communicated back to Mojito through the actionContext object.

    Models in Mojito rely on HTTP-based services to get data and do not generally connect directly to a database through an ORM. We recommend YQL to fetch data from Web services.

  3. Change to the tests directory.

  4. Edit controller.server-tests.js and replace the string ‘Mojito is working.’ in the code with ‘Doing well, thanks.’. Your controller.server-tests.js should look similar to the following code:

    YUI.add('hello-tests', function(Y) {
    
      var suite = new YUITest.TestSuite('hello-tests'),
          controller = null,
          A = YUITest.Assert;
    
      suite.add(new YUITest.TestCase({
    
        name: 'Hello user tests',
        setUp: function() {
          controller = Y.mojito.controllers["hello"];
        },
        tearDown: function() {
          controller = null;
        },
        'test mojit': function() {
          var ac,
              modelData,
              assetsResults,
              doneResults;
          modelData = { x:'y' };
          ac = {
            assets: {
              addCss: function(css) {
                assetsResults = css;
              }
            },
            models: {
              get: function() {
                return {
                  getData: function(cb) {
                    cb(null, modelData);
                  }
                };
              }
            },
            done: function(data) {
              doneResults = data;
            }
          };
          A.isNotNull(controller);
          A.isFunction(controller.index);
          controller.index(ac);
          A.areSame('./index.css', assetsResults);
          A.isObject(doneResults);
          A.areSame('Doing well, thanks.', doneResults.status);
          A.isObject(doneResults.data);
          A.isTrue(doneResults.data.hasOwnProperty('x'));
          A.areEqual('y', doneResults.data['x']);
        }
      }));
      YUITest.TestRunner.add(suite);
    }, '0.0.1', {requires: ['mojito-test', 'hello']});
    

    Mojito has the unit test given in controller.server-tests.js confirms that the output from the action index is the same as the string given in the assert statement.

  5. From the application directory, run the application test.

    $ mojito test app .

  6. Restart the server and reopen http://localhost:8666/ in a browser to see the updated text:

    status
           Doing well, thanks.
    data
           some: data
    
  7. Congratulations, now go try our code examples or check out the Mojito Documentation.