Mahjong Application Backend

Local development

Prerequisite

Node.Js
Typescript
Serverless
Java Runtime Engine (JRE) version 6.x or newer
(Important) Add a config file under .aws folder (C:\Users\USERNAME\.aws\config for Windows and ~/.aws/config for Unix-based systems)

Start local development

To start local dev, simply run:

yarn run start_local

Follow the steps below for detailed step breakdown:

Install dependencies

# Cleanup auto-generated folders
yarn run dev:cleanup

# Install dependencies
yarn run install_dep

Remember to uncomment the code for local dev in serverless.yml
(Important) Increase max space size for Node (otherwise, webpack may not work in your local machine)

export NODE_OPTIONS="--max-old-space-size=8192"

Install dynamodb local (this will create a folder called .dynamodb in the project root directory) and start serverless and dynamodb locally

yarn run dev:run

Test Connection here by entering the websocket url (e.g. ws://localhost:3001)

For more details on local dev, see the following links

To invoke lambda function locally see invoke-local

Deploy to AWS account

Add profile and credentials to .aws/credentials and ./aws/config file OR use aws-vault (Recommended):

aws-vault add gamblingkings-sls

Deploy or remove AWS resources
Note: --no-session flag seems to be required。 See this bug for more details

To deploy:

aws-vault exec <PROFILE_NAME> --no-session -- sls deploy

To remove:

aws-vault exec <PROFILE_NAME> --no-session -- sls remove

To start a production build and deploy to AWS:

yarn start

Websocket Test Data

SET_USERNAME

{
  "action": "SET_USERNAME",
  "payload": {
    "username": "new user"
  }
}

GET_ALL_USERS

{
  "action": "GET_ALL_USERS"
}

CREATE_GAME

{
  "action": "CREATE_GAME",
  "payload": {
    "game": {
      "gameName": "Chow Yun-fat，the Mahjong King",
      "gameType": "Mahjong",
      "gameVersion": "Japanese"
    }
  }
}

GET_ALL_GAMES

{
  "action": "GET_ALL_GAMES"
}

SEND_MESSAGE

{
  "action": "SEND_MESSAGE",
  "payload": {
    "username": "test user",
    "message": "custom message to all users"
  }
}

JOIN_GAME

{
  "action": "JOIN_GAME",
  "payload": {
    "gameId": "5938902b-2e2c-4da8-b900-5cdfbba8f10c"
  }
}

LEAVE_GAME

{
  "action": "LEAVE_GAME",
  "payload": {
    "gameId": "5938902b-2e2c-4da8-b900-5cdfbba8f10c"
  }
}

START_GAME

{
  "action": "START_GAME",
  "payload": {
    "gameId": "5938902b-2e2c-4da8-b900-5cdfbba8f10c"
  }
}

GAME_PAGE_LOAD

{
  "action": "GAME_PAGE_LOAD",
  "payload": {
    "gameId": "5938902b-2e2c-4da8-b900-5cdfbba8f10c"
  }
}

DRAW_TILE

{
  "action": "DRAW_TILE",
  "payload": {
    "gameId": "5938902b-2e2c-4da8-b900-5cdfbba8f10c"
  }
}

PLAY_TILE

{
  "action": "PLAY_TILE",
  "payload": {
    "gameId": "5938902b-2e2c-4da8-b900-5cdfbba8f10c",
    "tile": "1_DOT"
  }
}

PLAYED_TILE_INTERACTION

{
  "action": "PLAYED_TILE_INTERACTION",
  "payload": {
    "gameId": "5938902b-2e2c-4da8-b900-5cdfbba8f10c",
    "playedTiles": ["1_DOT", "1_DOT", "1_DOT"],
    "meldType": "TRIPLET",
    "skipInteraction": false
  }
}

WIN_ROUND

{
  "action": "WIN_ROUND",
  "payload": {
    "gameId": "5938902b-2e2c-4da8-b900-5cdfbba8f10c",
    "handPointResults": {
      "totalPoints": 3,
      "handPoints": 3,
      "extraPoints": 0,
      "windPoints": 0,
      "dragonPoints": 0,
      "flowerPoints": 0,
      "hands": [
        {
          "points": 3,
          "name": "ALL_TRIPLET"
        }
      ],
      "tiles": [
        {
          "type": "DOT",
          "value": 1
        },
        {
          "type": "DOT",
          "value": 1
        },
        {
          "type": "DOT",
          "value": 2
        },
        {
          "type": "DOT",
          "value": 2
        },
        {
          "type": "DOT",
          "value": 2
        },
        {
          "type": "DOT",
          "value": 3
        },
        {
          "type": "DOT",
          "value": 3
        },
        {
          "type": "DOT",
          "value": 3
        },
        {
          "type": "DOT",
          "value": 4
        },
        {
          "type": "DOT",
          "value": 4
        },
        {
          "type": "DOT",
          "value": 4
        },
        {
          "type": "CHARACTER",
          "value": 7
        },
        {
          "type": "CHARACTER",
          "value": 7
        },
        {
          "type": "CHARACTER",
          "value": 7
        }
      ],
      "wind": "EAST",
      "bonusTiles": [],
      "flower": 1,
      "concealedPoint": 0
    }
  }
}

SELF_PLAY_TILE

{
  "action": "SELF_PLAY_TILE",
  "payload": {
    "gameId": "5938902b-2e2c-4da8-b900-5cdfbba8f10c",
    "playedTile": "1_Dot",
    "isQuad": false,
    "alreadyMeld": false
  }
}

General user flow

connect x 4: Four users connect to websocket
CREATE_GAME: One user creates a game
JOIN_GAME x 3: Three other users join the game created by the host
START_GAME: Starts the game if there are four users in the game
GAME_PAGE_LOAD x 4: Wait until assets are loaded on the frontend for all four users
GAME_START: Officially starts the game if gameLoadedCount for the game in the Games table is 4
DRAW_TILE: Draw one tile and send it to a user in the game
LEAVE_GAME: To remove user from the Games table if user disconnects or manually leave a game. Note: if the user leaving the game is the game host, the game will be deleted
PLAY_TILE: Send a played tile to all users in the game
PLAYED_TILE_INTERACTION * 3: Interact with a played tile to make a meld (Consecutive, Triplet, or Quad), and the backend will decide who can take this tile based on meld priority. If all three other users decide not to take the tile, the tile can be skipped and not taken by anyone
SELF_PLAY_TILE: To play bonus tiles automatically at game start or during the game
WIN_ROUND: To win a game, update wind/dealer, and start a new game and distribute tiles to each user

Testing

Jest framework is used for testing
jest-dynalite is used to run test with a mock DynamoDB instance
jest-extended is used to add additional matchers to Jest's default ones

Configuration files

jest.config.js
jest-dynalite-config.js
global.d.ts: for ide or editor to recognize jest-extended library

Test folder

See test

TODOs on Optimization and Future Refactoring

Refactor and optimize addUserToGame call to DynamoDB
Refactor and optimize removeUserFromGame call to DynamoDB

Build Optimization

See this article to know more about how to optimize build time using typescript, serverless, webpack, and eslint

GamblingKings/GamblingKingsBackend