javascript - Php script is automatically being invoked multipletimes - Stack Overflow

admin管理员组

文章数量:1417406

I am facing a strange issue here. I am using javascript ajax(I used jquery). Now the scenario is;

One ajax call is invoking a php script which is basically a long running process and it sets some session variables.

Later in some intervals(lets say in each 2 sec) I am running another ajax calls to check the session variables to know when the process(first php script execution) is pleted.

First php script is fetching data from database and wring it into a file. In each fetching I am counting the loop number and storing it into a session variable to keep some kind of tracking record. Like;

 $i=0;
 $_SESSION['time']=date('m-d-Y H:i:s');
 while(...)
 {
     ini_set('session.use_only_cookies', false);
     ini_set('session.use_cookies', false);
     ini_set('session.use_trans_sid', false);
     ini_set('session.cache_limiter', null);
     session_start();
     $_SESSION['tracksatus']="loop number : ".$i." time is :"$_SESSION['time'];
     session_write_close();

     $i++;

     ......
     ......
 }

Another php script which I am invoking via setInterval ajax is just doing like;

 echo $_SESSION['trackstatus']

The set interval ajax is returning me like;

  loop number 1 time is m-d-Y H:i:s
  loop number 5 time is m-d-Y H:i:s
  loop number 8 time is m-d-Y H:i:s
  ......

Then after few call again;

  loop number 1 time is m-d-Y H1:i1:s1
  .....

Notice the change of H:i:s to H1:i1:s1

So as per my understanding the php script is invoking twice. And for your information same code was working just before 12 hrs may be. And I faced this issue before and somehow solved it(trial and error so I don't know how or may be automatically....ok actually I have no clue).

Can you please give me an insight what I am doing wrong? Please mention if you need more information.

And the funny thing is that it is working as expected just after asking this question without even changing a single line of code. But I want to know the reason.

I am facing a strange issue here. I am using javascript ajax(I used jquery). Now the scenario is;

One ajax call is invoking a php script which is basically a long running process and it sets some session variables.

Later in some intervals(lets say in each 2 sec) I am running another ajax calls to check the session variables to know when the process(first php script execution) is pleted.

First php script is fetching data from database and wring it into a file. In each fetching I am counting the loop number and storing it into a session variable to keep some kind of tracking record. Like;

 $i=0;
 $_SESSION['time']=date('m-d-Y H:i:s');
 while(...)
 {
     ini_set('session.use_only_cookies', false);
     ini_set('session.use_cookies', false);
     ini_set('session.use_trans_sid', false);
     ini_set('session.cache_limiter', null);
     session_start();
     $_SESSION['tracksatus']="loop number : ".$i." time is :"$_SESSION['time'];
     session_write_close();

     $i++;

     ......
     ......
 }

Another php script which I am invoking via setInterval ajax is just doing like;

 echo $_SESSION['trackstatus']

The set interval ajax is returning me like;

  loop number 1 time is m-d-Y H:i:s
  loop number 5 time is m-d-Y H:i:s
  loop number 8 time is m-d-Y H:i:s
  ......

Then after few call again;

  loop number 1 time is m-d-Y H1:i1:s1
  .....

Notice the change of H:i:s to H1:i1:s1

So as per my understanding the php script is invoking twice. And for your information same code was working just before 12 hrs may be. And I faced this issue before and somehow solved it(trial and error so I don't know how or may be automatically....ok actually I have no clue).

Can you please give me an insight what I am doing wrong? Please mention if you need more information.

And the funny thing is that it is working as expected just after asking this question without even changing a single line of code. But I want to know the reason.

• javascript
• php
• jquery
• ajax

Share Improve this question Follow edited Apr 28, 2017 at 5:49 KOUSIK MANDAL asked Apr 25, 2017 at 6:03 KOUSIK MANDALKOUSIK MANDAL 2,05211 gold badge2424 silver badges5151 bronze badges 8

• its because of while loop. – vijay Commented Apr 25, 2017 at 6:13
• not clear to me, please explain – KOUSIK MANDAL Commented Apr 25, 2017 at 6:16
• What does your AJAX look like? – user6137123 Commented May 2, 2017 at 2:20
• You do store sid in url, it can be cause index robots or prefetching restart the script with your sid if your service is publicly accessible. Is it? Also when the status date is changed it's worth to check process list. Was a new long-running process started? What is access log saying? Who requested the url? – origaminal Commented May 3, 2017 at 0:37
• I think you have the wrong solution to observe the progress of your script executes in ajax You should instead use the Jquery method ".then ()" to wait for the promise of your script. And if you want to observe the progress of your script you can always use the method ".progress ()" – Snoozer Commented May 3, 2017 at 13:06

 |  Show 3 more ments

5 Answers 5

Sorted by: Reset to default 3

I think that I know what the reason, PHP writes session variables to file, but it do it only on end of script execution, so you can`t see the changes of session in another script before end of long one.

You can fix it by adding session_write_close(); session_start(); after each change of session data.

session_write_close will write changes to HD, so another script can read it. session_start will load session from HD, but make sure that your another script make no changes for a session, these changes will be overwritten by your long script.

And one more thing if you are using separate domains: Before actual AJAX call happen your browser sends OPTIONS request to the same URL for checking CORS headers. So on start of your script check the HTTP METHOD and if it HEAD or OPTIONS make die();

Instead of using sessions, try using a temp file to keep count with a dynamic ID

Javascript

var time = Date.now();
$.get('/firstURL?time='+time);
setInterval(function(){
    $.get('/secondURL?time='+time, function(response){
        console.log(response);
    }
}, 1000);

PHP 1st URL

<?php

$id = $_GET['time'];
$count = 0;

while(...) {
    // Do your stuff

    $count++;
    file_put_contents("/tmp/{$id}", $count);
}

?>

PHP 2nd URL

<?php

$id = $_GET['time'];
$count = 0;

try {
    $count = file_get_contents("/tmp/{$id}");
} catch(Exception $e) {}

echo $count;

?>

As other have said PHP does not write the session until execution has finished. you better off creating a php function that you call that writes a file with the progress and then your second ajax call just reads the file.

function updateCreateProgress($jobStartTime, $progress){
    file_put_contents('/tmp/'.$jobStartTime.'.txt', $progress);
}

function pleteProgress($jobStartTime){
    unlink('/tmp/'.$jobStartTime.'.txt')
}

now your second script can check for '/tmp/'.$jobStartTime.'.txt' if it's there read it using file_get_contents if its not there report back it has finished.

Try adjusting to something like this:

$i=0;
ini_set('session.use_only_cookies', false);
ini_set('session.use_cookies', false);
ini_set('session.use_trans_sid', false);
ini_set('session.cache_limiter', null);
session_start();
 $_SESSION['time']=date('m-d-Y H:i:s');
 while(...)
 {

     $_SESSION['tracksatus']="loop number : ".$i." time is :"$_SESSION['time'];
     session_write_close();
     session_start();
     $i++;

     ......
     ......
 }

You started talking about $_SESSION before calling session_start();

If you call ajax with GET method - you must set "cache:false" option.

Yes, you must protect your php script from other requests. With unique key (GET parameter) or session.

php lock session data for single call and release it only when this call end. Using session_write_close() when script still working - bad practice. Maybe you want save into session something more after loop but before using this data from other requests.

Flexible and clear solution:

1) script1.php - invoke from ajax for start long job.

2) script2.php (long job here) - run directly from script1.php as background without wait, or add new cron job (insert into table) and run script2.php from cron (check jobs every second or other time).

3) script3.php - check job status (ajax).

For "munication" between script2.php and script3.php can be use database or special file with flock(), clearstatcache() and flush().

本文标签： javascriptPhp script is automatically being invoked multipletimesStack Overflow