Question

以下代码，如果我对run.py进行ajax调用，然后在html标记中显示输出。脚本run.py运行超过2分钟。但是在下面的js脚本中。一旦脚本开始运行。输出（输出的初始行）将显示在html标记中。不会显示脚本的剩余部分。

$(document).ready(function(){   

$(sub).click(function(){ 
    alert("connecting to host")
            $.ajax({
                type:'POST',
                url:'/cgi-bin/run.py', 
                dataType: 'html',                                        
                success:function (z) {
                     $('#output').html(z);



                }


        });

        }) ;
});

我想知道ajax中是否有任何函数要等到脚本完成（不仅仅是执行脚本。而是等到结束）然后将整个输出显示到html标记。

这是我的python脚本：

import sys, os
import cgi, cgitb

    def __init__(self, address, username, password):
    # connects to host


    def sendShell(self, command):
     #opens shell

    def process(self):

                while self.shell.recv_ready():
                    info += self.shell.recv(1024)
                output = str(info, "utf8")
                print(output)

hostname = "z.com"
password = "yyy"
username = "dd"   
connection = ssh(hostname, username, password)
connection.openShell()
connection.sendShell("date");

Answer 1

jQuery.ajax()有一个选项async: false，不过我会反对它并在ajax回调中做你需要的任何事情。此外，它已被弃用。

Answer 2

将$ .Ajax函数的async标志更改为false几乎是正确的，但在您的情况下，脚本需要运行很长时间，因此您需要考虑使用长轮询来处理此类请求。

原因是因为浏览器对ajax调用具有最大超时时间，并且通常设置为1分钟，具体取决于浏览器（因此在您的情况下，客户端/浏览器在1分钟后停止连接并希望响应，但您希望它等到它完成然后才发回响应）。因此，为了克服这个问题，你必须发送一次20秒或一次最大超时的另一个请求到py脚本以检查它是否完成。

javascript端的代码段：

function isDone(timestamp) {
    timestamp = timestamp || null;

    $.ajax({
        type:'POST',
        url:'/cgi-bin/run.py', 
        dataType: 'json',                                       
        data: { "timestamp": timestamp },
        timeout: 20000, // Or to whatever the max-timeout is, haven't checked that with jQuery.
        success: function (response) {
            if (response.done === false) {

                isDone(Date.now ());
            } else {
                // got the results, can continue.
                $('#output').html(response.output);
            }
        }
    });
}

isDone();

我不确定pyton脚本应该是什么样子，如果你想让你可以与我分享它，我会尝试完成服务器端。基本上你应该做的是将脚本的超时设置为最大值，并将正确的响应返回给客户端。

JSON响应应如下所示：

{
   "done": true, // or false if the script timed out.
   "output": html, // the variable that should contain the output when the py script is done, if its not done just send a null or don't send it back to the client at all.
   "timestamp": time.time() // if im not wrong that's how you get timestamp in py

}

伪代码中的服务器端：

Dynamcally or under setting, configure python script execution time to max or rather to 3 min, sense you mentioned it takes 2 min.

if (timestamp === null) { // first ajax call to this script.
    - Start long processing task.
    - Write the output to a file.
}

do { //  check this code block every 1 sec
    if (the file you are writing to was created and is complete / unlocked) {
        - Read from that file the content, save it into a variable and delete the file from your system.
        - Output the above mentioned response with done set to true and the current timestamp.
        - Break outside of the loop
    }

    if (timed out) { // basically check if 20 second passed sense starting timestamp.
        - Output the above mentioned response with done set to false and the current timestamp.
        - Break outside of the loop.
    }

    sleep for 1 sec, you don't want to kill your CPU usage.
} while (true)

等到脚本完成[ajax]

2 个答案: