In the last article, we cover the setup for the client-side of the application. Today we are going to look closely at server-side part. 🚀
Application API is written with Express framework for file serving and Websocket for communication. Entry file for server:
// ...
dotenv.config();
const port = process.env.PORT;
const app: Express = express();
const server = http.createServer(app);
app.use(express.static(path.join(__dirname, 'public')));
app.get('(/*)?', async (req, res, next) => {
res.sendFile(path.join(__dirname, 'public', 'index.html'));
});
AppDataSource.initialize().then(async () => {
console.info('Database connected');
}).catch((error) => {
console.error(error);
});
const io = new Server<IncomingEvents, OutgoingEvents, {}, User>(server, {
transports: ['websocket', 'polling'],
});
io.on('connection', (socket: Socket<IncomingEvents, OutgoingEvents, {}, User>) => {
registerUsersHandlers(io, socket);
registerCardsHandlers(io, socket);
registerBoardsHandlers(io, socket);
});
server.listen(port, () => {
// eslint-disable-next-line no-console
console.log(`Server is running at http://localhost:${port}`);
});
You can see we register events similar to what we did on client-side. That is because we are using the same set of events.
export type IncomingUsersEvents = {
Join: (data: {boardId: string, nickname: string; avatar: number;}) => void;
SetSelectedPlanningCard: (data: {selectedPlanningCard: number}) => void;
ToggleReady: () => void;
ChangeUserData: (data: {nickname: string, avatar: number}) => void;
}
export type OutgoingUsersEvents = {
Joined: (data: {
localUser: RawUser,
users: RawUser[],
cards: RawCard[],
board: {id: string, stage: number, maxVotes: number, timerTo: number, mode: string},
}) => void;
UserState: (data: {user: RawUser}) => void;
UsersState: (data: {users: RawUser[]}) => void;
}
export type IncomingCardsEvents = {
CreateCard: (data: {content: string, column: number}) => void;
UpdateCard: (data: {cardId: string, content: string}) => void;
DeleteCard: (data: {cardId: string}) => void;
GetCards: () => void;
GroupCards: (data: {cardId: string, stackedOn: string}) => void;
UngroupCards: (data: {cardId: string}) => void;
UpvoteCard: (data: {cardId: string}) => void;
DownvoteCard: (data: {cardId: string}) => void;
}
export type OutgoingCardsEvents = {
CardState: (data: {card: RawCard}) => void;
DeleteCard: (data: {cardId: string}) => void;
CardsState: (data: {cards: RawCard[]}) => void;
}
export type IncomingBoardsEvents = {
SetTimer: (data: {duration: number}) => void;
SetBoardMode: (data: { mode: string }) => void;
SetMaxVotes: (data: {maxVotes: number}) => void;
SetStage: (data: {stage: number}) => void;
}
export type OutgoingBoardsEvents = {
BoardConfig: (data: {board: {
stage: number,
timerTo: number,
maxVotes: number,
mode: string,
}}) => void;
}
export type IncomingEvents = IncomingUsersEvents & IncomingCardsEvents & IncomingBoardsEvents;
export type OutgoingEvents = OutgoingUsersEvents & OutgoingCardsEvents & OutgoingBoardsEvents;
And handlers are using these events as follows:
// ...
const registerCardsHandlers = (
io: Server<IncomingEvents, OutgoingEvents, {}, User>,
socket: Socket<IncomingEvents, OutgoingEvents, {}, User>,
) => {
socket.on('CreateCard', async ({ content, column }) => {
try {
if (Joi.string().min(1).max(512).validate(content).error) {
console.error(`CreateCard: Invalid content: ${content}`);
return;
}
if (Joi.number().allow(0, 1, 2).validate(column).error) {
console.error(`CreateCard: Invalid column: ${column}`);
return;
}
const card = await Cards.create({
content,
column,
board: {
id: socket.data.boardId,
},
user: {
id: socket.data.userId,
},
stackedOn: '',
votes: [],
}).save();
io.to(socket.data.boardId || '')
.emit('CardState', { card: getRawCard(card) });
} catch (error) {
console.error(error);
}
});
// ...
export default registerCardsHandlers;
To communicate with the backend server is using TypeORM. Initially, it has been connecting to Postgres but for my purpose, it was overkill so I switched to SQLite which is faster to provision, develop and maintain in this small app. If you want to switch back to Postgres it's just changing a few lines in the dataSource config.
import { DataSource } from 'typeorm';
import dotenv from 'dotenv';
import Boards from './Boards';
import Cards from './Cards';
import Users from './Users';
import Votes from './Votes';
dotenv.config();
const AppDataSource = new DataSource({
type: 'sqlite',
database: './db.sqlite',
synchronize: true,
logging: true,
entities: [Boards, Cards, Users, Votes],
subscribers: [],
migrations: [],
});
export default AppDataSource;
Models are simple entity classes that are extended TypeORM BaseEntity with some pre-made static methods to create and execute SQL queries.
export enum BoardMode {
RETRO= 'retro',
PLANNING_HIDDEN = 'planning_hidden',
PLANNING_REVEALED = 'planning_revealed',
}
@Entity()
export default class Boards extends BaseEntity {
@PrimaryGeneratedColumn('uuid')
id: string;
@OneToMany(() => Cards, (card) => card.board)
cards: Cards[];
@OneToMany(() => Users, (user) => user.board)
users: Users[];
@Column({
type: 'integer',
name: 'stage',
})
stage: number;
@Column({
type: 'integer',
name: 'max_votes',
})
maxVotes: number;
@Column({
type: 'varchar',
name: 'mode',
})
mode: string;
@Column({
name: 'timer_to',
})
timerTo: Date;
@CreateDateColumn({
name: 'created_at',
})
createdAt: Date;
@UpdateDateColumn({
name: 'updated_at',
})
updatedAt: Date;
}
TypeORM was a great choice for small API servers to use. And in compare to Sequelize it has much clear syntax and works pretty well with TypeScript.
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