Trader Desktop

This is an exercise in learning key web technologies using a simple trading scenario. We will use the following technologies and frameworks to complete this exercise:

Node.js
Socket.IO
jQuery
AngularJS
RequireJS
Sass/Compass

The application consists of a Node.js based server that accepts orders for trading stocks and 'places' the orders in the market.

The server may break a large order in to smaller chunks called 'placements' and push them to the market at different times.
A large order may not get filled in one shot, it may require several 'executions' to fill (depending on the supply and demand).
The server keeps the client informed about order progress by sending events over WebSockets.

Requirements

The server part is fully coded. You only need to code the client part providing the following functionality:

Allow the user to place orders.
Display the progress of orders in a table that is updated in real time. Listen to WebSocket messages from the server to implement this. If you have the Trader Desktop open in multiple browsers, they should all show the same information.
Bonus points: In addition to the table, implement a creative visualization to display the same information.

In order to help with debugging, also implement the following two functions:

Allow the user to delete all orders on the server.
Allow the user to "refresh" the desktop. This should drop all orders from the client and get a fresh copy from the server.

The screen shot below can be used to guide your front-end implementation:

For the purpose of this exercise, the trade button could pop up a dialog box asking for the number of trades to create. You can then just create that many trades using random symbols, quantities etc.

trader-desktop-angular-seed — the seed for Trader Desktop AngularJS app

This project is an application skeleton for a typical AngularJS web app modified for the Trader Desktop. You can use it to quickly bootstrap the project and dev environment for this project.

The seed contains a sample AngularJS application and is preconfigured to install the Angular framework and a bunch of development and testing tools for instant web development gratification.

The seed app doesn't do much, just shows how to wire two controllers and views together.

Getting Started

To get you started you can simply clone the trader-desktop-angular-seed repository and install the dependencies:

Prerequisites

You need git to clone the angular-seed repository. You can get it from http://git-scm.com/.

We also use a number of node.js tools to initialize and test angular-seed. You must have node.js and its package manager (npm) installed. You can get them from http://nodejs.org/.

Clone trader-desktop-angular-seed

Clone the angular-seed repository using git:

git clone https://github.com/sravanrekandar/trader-desktop-angular-seed.git
cd trader-desktop-angular-seed

Install Dependencies

We have two kinds of dependencies in this project: tools and angular framework code. The tools help us manage and test the application.

We get the tools we depend upon via npm, the node package manager.
We get the angular code via bower, a client-side code package manager.

We have preconfigured npm to automatically run bower so we can simply do:

npm install

Behind the scenes this will also call bower install. You should find that you have two new folders in your project.

node_modules - contains the npm packages for the tools we need
client/bower_components - contains the angular framework files

Note that the bower_components folder would normally be installed in the root folder but angular-seed changes this location through the .bowerrc file. Putting it in the app folder makes it easier to serve the files by a webserver.

Run the Application

We have preconfigured the project with a simple development web server. The simplest way to start this server is:

npm start

Now browse to the app at http://localhost:8080/.

Directory Layout in Client

client/                --> all of the files to be used in production
  css/              --> css files
    app.css         --> default stylesheet
  img/              --> image files
  index.html        --> app layout file (the main html template file of the app)
  index-async.html  --> just like index.html, but loads js files asynchronously
  js/               --> javascript files
    app.js          --> application
    controllers.js  --> application controllers
    directives.js   --> application directives
    filters.js      --> custom angular filters
    services.js     --> custom angular services
  partials/             --> angular view partials (partial html templates)
    partial1.html
    partial2.html

test/               --> test config and source files
  protractor-conf.js    --> config file for running e2e tests with Protractor
  e2e/                  --> end-to-end specs
    scenarios.js
  karma.conf.js         --> config file for running unit tests with Karma
  unit/                 --> unit level specs/tests
    controllersSpec.js      --> specs for controllers
    directivessSpec.js      --> specs for directives
    filtersSpec.js          --> specs for filters
    servicesSpec.js         --> specs for services

Testing

There are two kinds of tests in the angular-seed application: Unit tests and End to End tests.

Running Unit Tests

The angular-seed app comes preconfigured with unit tests. These are written in Jasmine, which we run with the Karma Test Runner. We provide a Karma configuration file to run them.

the configuration is found at test/karma.conf.js
the unit tests are found in test/unit/.

The easiest way to run the unit tests is to use the supplied npm script:

npm test

This script will start the Karma test runner to execute the unit tests. Moreover, Karma will sit and watch the source and test files for changes and then re-run the tests whenever any of them change. This is the recommended strategy; if your unit tests are being run every time you save a file then you receive instant feedback on any changes that break the expected code functionality.

You can also ask Karma to do a single run of the tests and then exit. This is useful if you want to check that a particular version of the code is operating as expected. The project contains a predefined script to do this:

npm run test-single-run

End to end testing

The angular-seed app comes with end-to-end tests, again written in Jasmine. These tests are run with the Protractor End-to-End test runner. It uses native events and has special features for Angular applications.

the configuration is found at test/protractor-conf.js
the end-to-end tests are found in test/e2e/

Protractor simulates interaction with our web app and verifies that the application responds correctly. Therefore, our web server needs to be serving up the application, so that Protractor can interact with it.

npm start

In addition, since Protractor is built upon WebDriver we need to install this. The angular-seed project comes with a predefined script to do this:

npm run update-webdriver

This will download and install the latest version of the stand-alone WebDriver tool.

Once you have ensured that the development web server hosting our application is up and running and WebDriver is updated, you can run the end-to-end tests using the supplied npm script:

npm run protractor

This script will execute the end-to-end tests against the application being hosted on the development server.

Updating Angular

Previously we recommended that you merge in changes to angular-seed into your own fork of the project. Now that the angular framework library code and tools are acquired through package managers (npm and bower) you can use these tools instead to update the dependencies.

You can update the tool dependencies by running:

npm update

This will find the latest versions that match the version ranges specified in the package.json file.

You can update the Angular dependencies by running:

bower update

This will find the latest versions that match the version ranges specified in the bower.json file.

Loading Angular Asynchronously

The angular-seed project supports loading the framework and application scripts asynchronously. The special index-async.html is designed to support this style of loading. For it to work you must inject a piece of Angular JavaScript into the HTML page. The project has a predefined script to help do this.

npm run update-index-async

This will copy the contents of the angular-loader.js library file into the index-async.html page. You can run this every time you update the version of Angular that you are using.

Serving the Application Files

While angular is client-side-only technology and it's possible to create angular webapps that don't require a backend server at all, we recommend serving the project files using a local webserver during development to avoid issues with security restrictions (sandbox) in browsers. The sandbox implementation varies between browsers, but quite often prevents things like cookies, xhr, etc to function properly when an html page is opened via file:// scheme instead of http://.

Running the App during Development

The angular-seed project comes preconfigured with a local development webserver. It is a node.js tool called http-server. You can start this webserver with npm start but you may choose to install the tool globally:

sudo npm install -g http-server

Then you can start your own development web server to serve static files from a folder by running:

http-server

Alternatively, you can choose to configure your own webserver, such as apache or nginx. Just configure your server to serve the files under the / directory.

Running the App in Production

This really depends on how complex is your app and the overall infrastructure of your system, but the general rule is that all you need in production are all the files under the client/ directory. Everything else should be omitted.

Angular apps are really just a bunch of static html, css and js files that just need to be hosted somewhere they can be accessed by browsers.

If your Angular app is talking to the backend server via xhr or other means, you need to figure out what is the best way to host the static files to comply with the same origin policy if applicable. Usually this is done by hosting the files by the backend server or through reverse-proxying the backend server(s) and webserver(s).

Continuous Integration

Travis CI

Travis CI is a continuous integration service, which can monitor GitHub for new commits to your repository and execute scripts such as building the app or running tests. The angular-seed project contains a Travis configuration file, .travis.yml, which will cause Travis to run your tests when you push to GitHub.

You will need to enable the integration between Travis and GitHub. See the Travis website for more instruction on how to do this.

Contact

For more information on AngularJS please check out http://angularjs.org/

urvijaykumar/trader-desktop-angular-seed