我正在按照this教程创建一个连接到mongodb的基本socket.io聊天室。这是代码：
const mongo = require('mongodb').MongoClient;
const client = require('socket.io').listen(3000).sockets;
// Connect to mongo
mongo.connect('mongodb://127.0.0.1/mongochat', function(err, db){
if(err){
throw err;
}
console.log('MongoDB connected...');
// Connect to Socket.io
client.on('connection', function(socket){
let chat = db.collection('chats');
// Create function to send status
sendStatus = function(s){
socket.emit('status', s);
}
// Get chats from mongo collection
chat.find().limit(100).sort({_id:1}).toArray(function(err, res){
if(err){
throw err;
}
// Emit the messages
socket.emit('output', res);
});
// Handle input events
socket.on('input', function(data){
let name = data.name;
let message = data.message;
// Check for name and message
if(name == '' || message == ''){
// Send error status
sendStatus('Please enter a name and message');
} else {
// Insert message
chat.insert({name: name, message: message}, function(){
client.emit('output', [data]);
// Send status object
sendStatus({
message: 'Message sent',
clear: true
});
});
}
});
// Handle clear
socket.on('clear', function(data){
// Remove all chats from collection
chat.remove({}, function(){
// Emit cleared
socket.emit('cleared');
});
});
});
});
代码运行，我得到了
（node：31737）DeprecationWarning：当前的URL字符串解析器是 已弃用，将在以后的版本中删除。要使用新的 解析器，将选项{useNewUrlParser：true}传递给MongoClient.connect。 MongoDB连接......
但是当我尝试在浏览器中获取html页面时，我得到了This 127.0.0.1 page can’t be found。
这是与server.js在同一文件夹上的index.html页面，该文件应该被渲染，但它不会：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" integrity="sha384-rwoIResjU2yc3z8GV/NPeZWAv56rSmLldC3R/AZzGRnGxQQKnKkoFVhFQhNUwEyJ" crossorigin="anonymous">
<title>MongoChat</title>
<style>
#messages{height:300px;}
</style>
</head>
<body>
<div class="container">
<div class="row">
<div class="col-md-6 offset-md-3 col-sm-12">
<h1 class="text-center">
MongoChat
<button id="clear" class="btn btn-danger">Clear</button>
</h1>
<div id="status"></div>
<div id="chat">
<input type="text" id="username" class="form-control" placeholder="Enter name...">
<br>
<div class="card">
<div id="messages" class="card-block">
</div>
</div>
<br>
<textarea id="textarea" class="form-control" placeholder="Enter message..."></textarea>
</div>
</div>
</div>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.0.3/socket.io.js"></script>
<script>
(function(){
var element = function(id){
return document.getElementById(id);
}
// Get Elements
var status = element('status');
var messages = element('messages');
var textarea = element('textarea');
var username = element('username');
var clearBtn = element('clear');
// Set default status
var statusDefault = status.textContent;
var setStatus = function(s){
// Set status
status.textContent = s;
if(s !== statusDefault){
var delay = setTimeout(function(){
setStatus(statusDefault);
}, 4000);
}
}
// Connect to socket.io
var socket = io.connect('http://127.0.0.1:4000');
// Check for connection
if(socket !== undefined){
console.log('Connected to socket...');
// Handle Output
socket.on('output', function(data){
//console.log(data);
if(data.length){
for(var x = 0;x < data.length;x++){
// Build out message div
var message = document.createElement('div');
message.setAttribute('class', 'chat-message');
message.textContent = data[x].name+": "+data[x].message;
messages.appendChild(message);
messages.insertBefore(message, messages.firstChild);
}
}
});
// Get Status From Server
socket.on('status', function(data){
// get message status
setStatus((typeof data === 'object')? data.message : data);
// If status is clear, clear text
if(data.clear){
textarea.value = '';
}
});
// Handle Input
textarea.addEventListener('keydown', function(event){
if(event.which === 13 && event.shiftKey == false){
// Emit to server input
socket.emit('input', {
name:username.value,
message:textarea.value
});
event.preventDefault();
}
})
// Handle Chat Clear
clearBtn.addEventListener('click', function(){
socket.emit('clear');
});
// Clear Message
socket.on('cleared', function(){
messages.textContent = '';
});
}
})();
</script>
</body>
</html>
"mongodb": "^3.1.0-beta4", v3.2.20 这个问题困扰了我几个小时，我没有线索。非常感谢你的帮助。