Backend Chat

HTTP and Socket.IO server for the Hexlet chat project. User accounts, channels and messages are stored in memory and reset when the server restarts.

Requirements

Node.js 22.12 or newer.

Install and run

npm install @hexlet/chat-server
npx start-server -s ./dist

The server listens on port 5001. It serves the client files from the directory passed with --static and returns its index.html for client routes such as /login.

Usage: start-server [OPTIONS]

Options:
  -v, --version            output the version number
  -a, --address <address>  address to listen on (default: "0.0.0.0")
  -p, --port <port>        port to listen on (default: 5001 or PORT)
  -s, --static <path>      path to static assets files (default: "./build")
  -h, --help               display help for command

REST API

All API endpoints exchange JSON. The following examples use the browser's Fetch API. This helper checks the HTTP status and parses the response.

const request = async (method, path, { token, body } = {}) => {
  const response = await fetch(`/api/v1${path}`, {
    method,
    headers: {
      ...(token ? { Authorization: `Bearer ${token}` } : {}),
      ...(body ? { 'Content-Type': 'application/json' } : {}),
    },
    ...(body ? { body: JSON.stringify(body) } : {}),
  });
  if (!response.ok) {
    throw new Error(`HTTP ${response.status}`);
  }
  return response.json();
};

Create a user and log in

const user = await request('POST', '/signup', {
  body: { username: 'newuser', password: '123456' },
});
// { token: '...', username: 'newuser' }

const { token } = await request('POST', '/login', {
  body: { username: 'admin', password: 'admin' },
});

Signup returns status 201, or 409 if the username already exists. Login returns status 200, or 401 if the credentials are invalid. Channel and message endpoints require the returned token in the Authorization header.

Channels

const channels = await request('GET', '/channels', { token });
// [{ id: '1', name: 'general', removable: false }, ...]

const channel = await request('POST', '/channels', {
  token,
  body: { name: 'new channel' },
});
// { id: '...', name: 'new channel', removable: true }

const renamedChannel = await request('PATCH', `/channels/${channel.id}`, {
  token,
  body: { name: 'renamed channel' },
});

const removedChannel = await request('DELETE', `/channels/${channel.id}`, { token });
// { id: '...' }

Messages

const messages = await request('GET', '/messages', { token });

const message = await request('POST', '/messages', {
  token,
  body: { body: 'hello', channelId: channels[0].id, username: 'admin' },
});
// { id: '...', body: 'hello', channelId: '1', username: 'admin', removable: true }

const editedMessage = await request('PATCH', `/messages/${message.id}`, {
  token,
  body: { body: 'updated message' },
});

const removedMessage = await request('DELETE', `/messages/${message.id}`, { token });
// { id: '...' }

Socket.IO events

Mutations through the REST API broadcast the same JSON response to connected Socket.IO clients.

| Event | Payload | | --- | --- | | newChannel | Created channel | | renameChannel | Updated channel | | removeChannel | { id } | | newMessage | Created message | | renameMessage | Updated message | | removeMessage | { id } |

import { io } from 'socket.io-client';

const socket = io();
socket.on('newMessage', (message) => {
  console.log(message);
});

Development and releases

The source lives in the server/ directory of the chat project. Run these commands from that directory.

make install
make lint
make test
npm audit

Version 3 uses Fastify 5 and requires Node.js 22.12 or newer. The REST endpoints and Socket.IO event names are unchanged. Applications that import the Fastify plugin must also use Fastify 5.

GitLab CI tests the server on pushes. Releases are published by hand with release-it and need an npm account with publish rights in the @hexlet scope.

npm login
make release                    # asks for patch / minor / major
npx release-it --no-increment   # publishes the version already in package.json

release-it requires a clean working tree. It bumps the version in package.json and package-lock.json, commits, tags the commit chat-server-v<version>, pushes the tag and publishes the package to npm.