Keno Server

A simple server for a Keno lottery game, built using ExpressJS. Comes with an AngularJS front-end to test the API.

You can view this application live on https://keno-server.azurewebsites.net/

Build & Run

Follow these steps if you want to run the server on your own machine locally.

Build

1. Make sure you have NodeJS, npm, and git installed; execute these commands in a terminal.
2. git clone https://github.com/charliegdev/keno-server.git
3. cd keno-server
4. npm install

The source code is ready. Check out the next section on how to launch the server and see it in action.

Run

There are 2 ways to run this:

1. For prod server, run npm start.
2. For dev server, run npm run nodemon. This would start nodemon, which automatically restarts the NodeJS server whenever we make changes to the source code.

Go to http://localhost:3000 to see the Keno server API tester page.

[Optional] Babel for Front-end JavaScript

If you don't plan to change any of the front-end JavaScript code under the public/es6 folder, you can skip this section.

However, if you do plan to do so, launch another terminal and run

npm run babel

That command will run babel in watch mode, and convert front-end ES6 code into ES5 anytime you make any change. If you don't plan to modify any front-end code, you don't need to run babel. Check the Structure section for more information about front-end code structure.

The server side code uses ES6 as well; as long as you have a reasonably up-to-date LTS version for Node.js (newer than 5.12), you should be fine without Babel.

Use

Once the server is launched, http://localhost:3000 will show the front-end test page for the server.

Press the blue "Start a Random Pick" button to generate:

• 5 - 10 random numbers between 1 and 80;
• A random wager between 1 and 100.

After that, these things happen automatically behind the scene:

1. The client sends the information to the back-end server using the races endpoint. The naming of the endpoint mimics Keno Caveman.
2. The server does the calculation, and returns the result to the front-end.
3. Once the front-end gets the result, it'll display the result in the table. Gray rows mean you didn't win any money; green rows mean you did.

The front-end is basically a text-based Keno game without the lottery UI; it mimics the gameplay of Keno Caveman, without the egg mechanism. It uses the pay table in Caveman as well.

Structure

This Express application is created using Express Application Generator. Here is a breakdown of the codebase structure:

• bin: the config folder for the server; NodeJS uses bin/www to launch the server.
• keno-math: gameplay related logic; separated from any Express logic. Winnings are calculated here.
• routes: Express-related logic to handle user's API calls. Right now it only handles races call; it delicates the actual gameplay calculation to modules in keno-math.
• public: front-end for the server done by AngularJS and Bootstrap 4. This front-end is included as a convenient way to test the server, but it's not required for the server's functionality. In a real environment, this public folder can be the location where we put the real game client.
  • public/es6: Source file for ECMAScript 2016.
  • public/dist: Transpiled file generated by Babel. This file is referenced in index.html.

Express Application Generator generates a views folder by default, with pug as the template language. However, since I already made a single-page front-end app in AngularJS, the views folder is not needed, therefore removed.

Response Structure

A response to a races contains a JSON which looks like this:

{
  "data": {
    "draw": {
      "created": "2018-07-01T01:37:46.894Z",
      "hit_count": 1,
      "id": "ae56e13e-7183-4310-a1bb-544ceb7aec02",
      "reward": 0,
      "spots_count": 5,
      "spots_drawn": [77,37,27,40,6,79,2,72,48,38,17,53,45,19,58,69,71,49,8,59],
      "spots_played": [23,7,30,48,33], 
      "wager": 7
    },
    "id": "ae56e13e-7183-4310-a1bb-544ceb7aec02",
    "reward_key": "5a44cf0c-c98d-40ba-8ce8-da3a3855eb38",
    "wager": 7,
    "winner": false
  },
  "type": "basicKeno#play"
}

It was structured that way specifically to mimic real responses in Keno Caveman.

Defects and Todos

Please see the "Project" section of this repo on GitHub.