Nest JS based Chat server with API and websocket gateway

Chat server using WebSockets with Nest framework.

Installation

npm install

Running the app

# development
npm run start

# watch mode
npm run start:dev

Required packages

npm i --save @nestjs/websockets @nestjs/platform-socket.io ngx-socket-io
npm i --save-dev @types/socket.io

Web Socket Gateway

• Init:

  We add @WebSocketServer() server; inside of our ChatWebsocketGateway to attaches a native Web Socket Server to our property server which is real-time, bidirectional and event-based communication between the client and the server

• Handlers:

  To handle the connection and disconnection at our websocket server we need implement interfaces OnGatewayConnection and OnGatewayDisconnect.

• Subscribers:

  We use decorator @SubscribeMessage('exchanges') on the method that handles our messagin rules on exchanges events,

APIs

RoomsController

• Create room:

  Resource:

    /api/v1/rooms
  

  Body:

    roomId: the room id (room name)
    creatorUsername: the username with creats the room
  

  Example:

  curl -X POST 'http://localhost:3000/api/v1/rooms' \
  --data-raw '{
      "roomId": "3XX",
      "creatorUsername": "Dhoni"
  }'

  Error cases:

  • Invalid body:

  {
    "statusCode": 400,
    "message": [
      "roomId should not be empty",
      "creatorUsername should not be empty"
    ],
    "error": "Bad Request"
  }

  • Existing room id:

  {
    "code": "room.conflict",
    "message": "Room with 'exmple-room' already exists"
  }

• Get room messages:

  Resource:

    /api/v1/rooms/{roomId}/messages
  

  Params:

    roomId: the room id
  

  Example:

  curl -X GET 'http://localhost:3000/api/v1/rooms/123/messages'

  Error cases:

  • Invalid room id (ex: not found or closed):

  {
    "code": "access-forbidden",
    "message": "The access is forbidden"
  }

• Close room (Delete room):

  Resource:

    /api/v1/rooms/{roomId}
  

  Params:

    roomId: the room id
  

  Example:

  curl -X DELETE http://localhost:3000/api/v1/rooms/123

  Error cases:

  • Invalid room id (ex: not found or closed):

  {
    "code": "room.not-found",
    "message": "Room with '3XX' not found"
  }