node.js长轮询事件循环破坏整个代码

Question

我是一个全新的编程和开发我的网站的这个阶段，我需要设置一个简单的长轮询请求，从数据库获得最新的消息，然后显示给客户机。我昨天创建了一个消息系统，现在它保存了消息和用户之间所有需要的关系······

以下是我所做的：

var express = require('express');
var router = express.Router();
var Conversation = require('../models/conversation');
var Promise = require('promise');

// Get Homepage
router.get('/', function(req, res){
	res.render('index');
});


var messages = [];
router.get('/inbox', function(req, res){
	var promise = new Promise(function (resolve, reject) {
		req.user.conversations.forEach(function(id){
			Conversation.getConversationById(id, function(err, conv){
				if (conv){
					messages.push(conv);
					if(messages.length == req.user.conversations.length){
						resolve(messages);
						messages = [];
					}
				} else {
					console.log(err);
				}
			});
		});
	}).then(function(object){
		res.render('inbox', {convers: object});
	}).catch(function(err){
		console.log(err);
	});
});

// Add new messages to messagesArray -> mesgArray to display them
var mesgArray = [];
var userIdFor = "";
router.post('/messages', function(req, res){
	var convId = req.body.conversationId;
	userIdFor = req.user.id;
	var promise = new Promise(function(resolve, reject){
		Conversation.getConversationById(convId, function(err, conver){
			if (err){
				console.log(err);
			} else {
				conver.messages.forEach(function(messa){
					mesgArray.push({msg: messa.msg, owner: messa.msgOwner, ownerName: messa.msgOwnerName});
					if(mesgArray.length == conver.messages.length){
						resolve(mesgArray);
					}
				});
			}
		});
	}).then(function(object){
		res.send({allMessages: object, userId: userIdFor});
		mesgArray = [];
		userIdFor = "";
	}).catch(function(err){
		console.log(err);
	});
});

// Save posted message to existent conversation
router.post('/saveMsg', function(req, res){
	var conversationId = req.body.conversationId;
	var messageToSave = req.body.message;
	console.log(messageToSave);
	console.log(conversationId);
	Conversation.getConversationById(conversationId, function(err, conversation){
		if (err){
			console.log(err);
		} else {
			Conversation.getConversationById(conversationId, function(err, conversation){
				if(err){
					console.log(err)
				} else {
					conversation.messages.push({
						msg: messageToSave,
						msgOwner: req.user.id,
						msgOwnerName: req.user.firstName
					});
					conversation.save(function(err){
						if(err){
							console.log(err);
						}
					})
				}
			});
		}
	});
});

module.exports = router;

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.2.3/jquery.min.js"></script>
<!-- REPLAY MESSAGE BOX -->
<div class="contact-form-container hidden-mode">
  <div class="row hide-contact text-right">
    <img src="/images/close.png">
  </div>
  <form>
    <div class="inbox-all-messages-container">
      <div class="row inbox-all-messages">
         <!-- Here will be all the messages -->
      </div>
      <div class="row text-center inbox-send-input">
        <div class="col-lg-11 col-md-11 col-sm-11">
          <textarea class="inbox-message-response-txt" placeholder="Type your message here"></textarea>
        </div>
        <div class="col-lg-1 col-md-1 col-sm-1 text-center inbox-message-send-btn">
          <p class="inbox-message-send-msg-btn">Send</p>
        </div>
      </div>
    </div>
  </form>
</div>
<script>
  $(document).ready(function(){

  var convId = "";
  $('.inbox-messager').on('click', function(){
    $('.inbox-all-messages').empty();
      var conversationId = this.getAttribute("data-conv-id");
      convId = conversationId;
      $.ajax({
        url: '/messages',
        method: 'POST',
        contentType: 'application/json',
        data: JSON.stringify({conversationId: conversationId}),
        success: function(response){
          response.allMessages.forEach(function(message){
            if(message.owner == response.userId){
              $('.inbox-all-messages').append(
                '<div class="row inbox-message-structure-meNot">'+
                  '<div class="row inbox-message-header">'+
                      '<div class="inbox-message-ava col-lg-1 col-md-1 col-sm-1">'+
                        '<img src="/images/avatar.jpg" class="inbox-message-header-ava-img">'+
                      '</div>'+
                      '<div class="inbox-message-header-senderName col-lg-3 col-md-3 col-sm-3">'+
                        '<p>' + message.ownerName + '</p>'+
                      '</div>'+
                      '<div class="col-lg-3 col-lg-offset-5 col-md-3 col-md-offset-5 col-sm-3 col-sm-offset-5 inbox-message-header-sentTime text-right">'+
                        '<p>24/05/2016</p>'+
                      '</div>'+
                  '</div>'+
                  '<div class="row inbox-message-body">'+
                    '<div class="col-lg-9 col-lg-offset-1 col-md-9 col-md-offset-1 col-sm-9 col-sm-offset-1 text-left">'+
                      '<p>' + message.msg + '</p>'+
                    '</div>'+
                  '</div>'+
                '</div>'
              );
              
            } else {
              $('.inbox-all-messages').append(
                '<div class="row inbox-message-structure-me">'+
                  '<div class="row inbox-message-header">'+
                      '<div class="inbox-message-ava col-lg-1 col-md-1 col-sm-1">'+
                        '<img src="/images/client.jpg" class="inbox-message-header-ava-img">'+
                      '</div>'+
                      '<div class="inbox-message-header-senderName col-lg-3 col-md-3 col-sm-3">'+
                        '<p>' + message.ownerName + '</p>'+
                      '</div>'+
                      '<div class="col-lg-3 col-lg-offset-5 col-md-3 col-md-offset-5 col-sm-3 col-sm-offset-5 inbox-message-header-sentTime text-right">'+
                        '<p>24/05/2016</p>'+
                      '</div>'+
                  '</div>'+
                  '<div class="row inbox-message-body">'+
                    '<div class="col-lg-9 col-lg-offset-1 col-md-9 col-md-offset-1 col-sm-9 col-sm-offset-1 text-left tester">'+
                      '<p>' + message.msg + '</p>'+
                    '</div>'+
                  '</div>'+
                '</div>'
              );
            }
          });
          $('.inbox-all-messages').append('<div id="bottom"></div>');
          $('.inbox-all-messages').scrollTo('#bottom', 100, "max");
        }
      });
      $('.contact-form-container').removeClass('hidden-mode');
      $('.messenger-contaner').addClass('stop-scroll');
      
  });

  $('.hide-contact').on('click', function(){
    $('.contact-form-container').addClass('hidden-mode');
    $('.messenger-contaner').removeClass('stop-scroll');
  });

  $('.inbox-message-send-msg-btn').on('click', function(){
    var messageToSend = $('.inbox-message-response-txt').val();
    $.ajax({
      url: '/saveMsg',
      method: 'POST',
      contentType: 'application/json',
      data: JSON.stringify({message: messageToSend, conversationId: convId}),
      success: function(response){
        alert('le message a bien ete enregistree');
      }
    });
  });
})

</script>

对不起，我的英语不好！非常感谢你在那里为我们服务！

Answer 1

如果您像您所说的那样对编程是完全陌生的，那么与其尝试从零开始创建您有困难的功能，也许使用一个有效的解决方案会是一个更好的主意。

您可以使用socket.io进行此类操作。它使用长轮询，并尝试升级到WebSocket（如果支持的话）。使用起来非常简单。下面是向客户机发送请求的服务器的整个工作示例：

var path = require('path');
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
app.get('/', (req, res) => {
  res.sendFile(path.join(__dirname, 'si.html'));
});
io.on('connection', s => {
  for (var t = 0; t < 3; t++)
    setTimeout(() => s.emit('message', 'message from server'), 1000*t);
});
http.listen(3002, () => console.error('listening on http://localhost:3002/'));

下面是客户端上的整个JavaScript代码：

var l = document.getElementById('l');
var log = function (m) {
    var i = document.createElement('li');
    i.innerText = new Date().toISOString()+' '+m;
    l.appendChild(i);
}
log('opening socket.io connection');
var s = io();
s.on('connect_error', function (m) { log("error"); });
s.on('connect', function (m) { log("socket.io connection open"); });
s.on('message', function (m) { log(m); });

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