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I am developing an web application using php and mysql along with AJAX. In one of my script there is a provision to fetch data from mysql table. But what if I want to cancel the execution of the php script which I am calling to get the data, in the middle of the execution? Let me clear it more. Like if it takes say 30 minutes to complete an AJAX call due to the heavy loop and I want to exit from that call before completion by clicking some button. How can I achieve that goal. Otherwise, my script is running well except that it hangs if I don't want to wait for the final AJAX response text and try to switch to other page of the web application.

samlancer
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2 Answers2

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You can create script like this:

$someStorage->set($sessionId . '_someFuncStop', true);

Call it through AJAX, when button STOP pressed.

In your script with loop check that var from storage

while(1) {
    if ($someStorage->get($sessionId . '_someFuncStop') === true ) break;
}
Animir
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To my best knowledge, PHP doesn't support some sort of event listeners that can interrupt running script by an external cause.

There are 2 paths you might want to consider (if you don't want to write shell scripts on the server that would terminate system processes that execute the script):

  1. ignore_user_abort function, thoug it is not 100% reliable

http://php.net/manual/en/function.ignore-user-abort.php

  1. Inside the loop you wish to terminate, create a database call (or read from a file), where you can set some kind of flag and if that flag is set, run a break/return/die command inside the script. The button you mentioned can then write to database/file and set the interrupt flag. (In general this is not really useful for script interruptions, since most scripts run in tens of milliseconds and the flag would not be set fast enough to terminate the script, in tens of minutes however, this is a viable solution.)
Michal Sukupčák
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