基于 Context API 和 Socket.IO 实现房间内用户列表显示

// 假设 users 是一个存储用户信息的对象，键为 socket ID，值为包含用户信息的对象
// 例如： users = { 'socketID1': { displayName: 'User1', room: 'room1' }, 'socketID2': { displayName: 'User2', room: 'room1' }, ... }

io.on('connection', (socket) => {
  console.log('User connected:', socket.id);

  socket.on('joinRoom', (data) => {
    const { room, displayName } = data;
    socket.join(room);

    // 将用户信息存储到 users 对象中
    users[socket.id] = { displayName: displayName, room: room };

    // 向房间内的所有用户广播更新后的用户列表
    io.to(room).emit('newUserResponse', getUsersInRoom(room));
  });

  socket.on('disconnect', () => {
    console.log('User disconnected:', socket.id);

    // 从 users 对象中移除用户信息
    const room = users[socket.id]?.room;
    delete users[socket.id];

    // 向房间内的所有用户广播更新后的用户列表
    if(room){
        io.to(room).emit('newUserResponse', getUsersInRoom(room));
    }
  });
});

// 获取指定房间内的用户列表
function getUsersInRoom(room) {
  const usersInRoom = [];
  for (const socketId in users) {
    if (users[socketId].room === room) {
      usersInRoom.push({ socketID: socketId, currentUser: { displayName: users[socketId].displayName } });
    }
  }
  return usersInRoom;
}

import React, { useContext, useState, useEffect } from 'react';
import { AuthContext } from './AuthContext'; // 替换为你的 AuthContext 路径
import { RoomContext } from './RoomContext'; // 替换为你的 RoomContext 路径

const ChatMembers = ({ socket }) => {
  const currentUser = useContext(AuthContext);
  const [users, setUsers] = useState([]);
  const { room } = useContext(RoomContext);

  useEffect(() => {
    const handleNewUserResponse = (data) => {
      setUsers(data);
    };

    socket.on("newUserResponse", handleNewUserResponse);

    // Clean up the event listener when the component unmounts
    return () => {
      socket.off("newUserResponse", handleNewUserResponse);
    };
  }, [socket, room]); //  room 作为依赖项，确保房间改变时更新用户列表

  return (
    <div>
      {users.map((user) => (
        <p key={user.socketID}>{user.currentUser.displayName}</p>
      ))}
    </div>
  );
};

export default ChatMembers;

import React, { createContext, useState } from 'react';

export const RoomContext = createContext();

export const RoomProvider = ({ children }) => {
  const [room, setRoom] = useState('');

  const value = {
    room,
    setRoom,
  };

  return (
    <RoomContext.Provider value={value}>
      {children}
    </RoomContext.Provider>
  );
};