使用jQuery和AJAX进行长轮询的正确方法是什么 [英] What is the proper way of doing long polling using jQuery and AJAX

问题描述

我有一个涉及实时通知的项目。所以我偶然发现使用socket io但我还没有足够的时间来学习它。所以我尝试用AJAX和jQuery来做。下面是我的代码结构，我想知道这是否会没有缺点？

I have a project which involves live notification. So I stumbled upon using socket io but I didn't have enough time to learn it yet. So I tried doing it with AJAX and jQuery. Below is my code structure and I was wondering if this is gonna work with no drawbacks?

setInterval(function(){
  if( !element.hasClass('processing') ){
    element.addClass('processing');
    $.ajax({
      type:         'post',
      dataType:     'json',
      url:      ajaxurl,
      data:         {},
      success:  function( response ){
        /* Success! */
        element.removeClass('processing');
      }
    });
  }
}, 2500);

推荐答案

一些额外信息

您描述的方式将起作用。从经验中我想指出一些事情。

Some Extra Info

The way you described will work. From Experience I would just like to point out some things.

• 我通常做一个递归函数，让你等待你的间隔在ajax呼叫之间而不是固定费率。 //可选但是给服务器一些呼吸室。

• I usually do a recursive function, allows you to wait your interval between ajax calls and not a fixed rate. //OPTIONAL BUT DOES GIVE THE SERVER SOME BREATHING ROOM.

使用带有isActive标志的window.setTimeout（）。 //允许你停止投票，无论原因是什么，并且因为需要再次启动功能

Use window.setTimeout() with an isActive flag. //ALLOWS YOU TO STOP POLLING FOR WHATEVER REASON, AND BECAUSE FUNCTION IS RECURSIVE START UP AGAIN IF NEED BE

为了彻底清醒，我发现它是总是一个好主意来处理$ .ajax（）帖子的错误情况。您可以显示一些消息，告诉用户他不再连接到互联网等。

For Sake of being thorough, I found it is always a good idea to handle the error case of the $.ajax() post. You could perhaps display some message telling the user he is no longer connected to the internet etc.

一些示例代码：

var isActive = true;

$().ready(function () {
    //EITHER USE A GLOBAL VAR OR PLACE VAR IN HIDDEN FIELD
    //IF FOR WHATEVER REASON YOU WANT TO STOP POLLING
    pollServer();
});

function pollServer()
{
    if (isActive)
    {
        window.setTimeout(function () {
            $.ajax({
                url: "...",
                type: "POST",
                success: function (result) {
                    //SUCCESS LOGIC
                    pollServer();
                },
                error: function () {
                    //ERROR HANDLING
                    pollServer();
                }});
        }, 2500);
    }
}

注意

这只是我使用您使用的确切方法获取的一些内容，似乎Web套接字可能是更好的选择，我将在不久的将来深入探讨。

NOTE

This is just some things I picked up using the exact method you are using, It seems that Web Sockets could be the better option and I will be diving into that in the near future.

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