我们可以获取 Ajax 调用的状态，例如 20% 已完成吗？

Question

Am calling an ajax call to validate n number of data.
Since it takes lot of time to complete, I thought of showing the user the progress bar or tell that 1/n completed
In-order to display that, I should get the status from the controller.

Can someone please tell me is there any way to get the status from controller before completing? Or Is there any other better way to implement.

Answer 1

Since ordinary AJAX is a classic request-response you cannot get progress information from the server with the same connection. You have to make a new AJAX call to ask the server for the task progress. This is called a heartbeat pooling technique.

Better solution is to use some kind of persistent connection, for example Websockets. That way server can push a message with progress information to the client over the same connection that initiated the task. Websocket adoption is strong among browsers.

Answer 2

XMLHttpRequest Monitoring progress:

see here: https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest#Monitoring_progress

more here: How to get progress from XMLHttpRequest

looks like this is in the standard https://www.w3.org/TR/progress-events/#firing-events-using-the-progressevent-interface-for-http

Answer 3

You Could try the following : In the php file you request with your AJAX call you could set a $var that contains the process. For Example you increment the var every 5 lines. After increment you call a Function that do the Animation process or just echo the process status in percent .

<?php

  $process = 0;


   function foo(){
      doSomething();
      $process++;
      showProcess();
   }

   function showProcess($process){
       echo $process;
      //some lazy effects 
   }
?>

Negative Aspect of this Method would be that (belongs to complexitivity) your programm will be a bit slower.