回声/打印东西到页面延迟在PHP中

Question

I want to make a page that will show some results after executing some processes. Each process may take 2-10 seconds. So instead of waiting for all the processes to complete, I want to print the result of each once it is completed.

Eg:

<?php

echo "1";

sleep(5); // some process that will execute 5 seconds

echo "2"

sleep(8); // some process that will execute 8 seconds

echo "3"

sleep(5); // some process that will execute 5 seconds

?>

So on opening this PHP file in browsers, "1" prints, after 5 seconds "2" and son on. How can I do that I PHP? One way to do that is to convert these to separate PHP files and load each of then with ajax. But I don't want to split it into different files.

Answer 1

use actions to separate the different parts of the script. that way you don't have to break into separate scripts.

$action = empty($_REQUEST['action']) ? null : $_REQUEST['action'];
switch($action){
    case 1:
        // do stuff
        break;
    case 2:
        // do stuff
        break;
    case 3:
        // do stuff
        break;
    case 4:
        // do stuff
        break; 
    default:
        echo "you fucked up";   
}

Then use ajax like

function doAjax(action){
  if('undefined' == typeof(action)) action = 1;
  var xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    if (xhttp.readyState == 4 && xhttp.status == 200) {
      document.getElementById("results").innerHTML = xhttp.responseText;
      action++;
      if(action<4) doAjax(action);
    }
  };
  xhttp.open("GET", "myPHPScript.php?action="+encodeURIComponent(action), true);
  xhttp.send();
}
doAjax();