我正在尝试制作一个简单的聊天应用程序，并保存对话的历史记录，这样当用户连接到它时，它就可以出现在页面上。如果我加载页面，它就不起作用，但如果我更改了任何服务器(甚至只点击ctrl+S，这会使nodemon重新加载服务器(，它会根据我的意愿添加消息。为什么会发生这种情况？
//server.js
const mongoose = require('mongoose');
const Msg = require('./models/messages')
const io = require('socket.io')(3000, {
cors: {
origin: "*"
}
})
const mongoDB = 'mongodb+srv://12345678:jonasjonas@cluster0.ifsxq.mongodb.net/message-database?retryWrites=true&w=majority'
mongoose.connect(mongoDB).then(() => console.log('connected'))
const users = {};
io.on('connection', (socket) => {
console.log('new user');
Msg.find().then(result => {
socket.emit('output-message', result);
})
socket.on('username', myname => {
users[socket.id] = myname;
socket.broadcast.emit('user-connected', myname)
})
socket.on('send-chat-message', message => {
const msg = new Msg({message:message, user:users[socket.id]});
msg.save().then(() => {
socket.broadcast.emit('chat-message', {message:message, name:users[socket.id]})
})
})
})
const socket = io('http://localhost:3000');
var messageContainer = document.getElementById('message-container')
var messageForm = document.getElementById('send-container')
var myname = prompt('Qual é o seu nome?');
appendMessage('You joined')
socket.emit('username', myname);
socket.on('chat-message', data => {
appendMessage(`${data.name}: ${data.message}`);
})
socket.on('output-message', data => {
for(let i = 0; i < data.length; i++) appendMessage(`${data[i].user}: ${data[i].message}`);
console.log(data)
})
socket.on('user-connected', myname =>
{appendMessage(`${myname} connected`)}
)
messageForm.addEventListener('submit', e => {
e.preventDefault();
const message = document.getElementById('message-input').value;
socket.emit("send-chat-message", message);
appendOwnMessage(`You: ${message}`);
document.getElementById('message-input').value = '';
})
function appendMessage(message) {
const a = document.createElement('div');
const b = a.appendChild(document.createElement('p'))
b.innerText = message;
b.setAttribute("class", "received")
messageContainer.append(a)
}
function appendOwnMessage(message) {
const a = document.createElement('div');
const b = a.appendChild(document.createElement('p'));
b.innerText = message;
b.setAttribute("class", "sent")
messageContainer.append(a)
}<script defer src='http://localhost:3000/socket.io/socket.io.js'></script>
<script defer src='script.js'></script>
<link href="style.css" rel="stylesheet" type="text/css" />
</head>
<body>
<div id='test'></div>
<div id= 'message-container'></div>
<div id='test'></div>
<form id='send-container'>
<input id="message-input" type='text'>
<button type='submit' id='send-button'>Send</button>
</form>在等待用户名之前注册侦听器。你错过了消息。
socket.on('chat-message', data => {
appendMessage(`${data.name}: ${data.message}`);
})
socket.on('output-message', data => {
for(let i = 0; i < data.length; i++) appendMessage(`${data[i].user}: ${data[i].message}`);
console.log(data)
})
socket.on('user-connected', myname =>
{appendMessage(`${myname} connected`)}
)
var myname = prompt('Qual é o seu nome?');
appendMessage('You joined')
socket.emit('username', myname);
您还可以考虑在他们注册用户名后发送消息。
socket.on('username', myname => {
Msg.find().then(result => {
socket.emit('output-message', result);
})
users[socket.id] = myname;
socket.broadcast.emit('user-connected', myname)
})