Display different message in case of timeout

Question

I have an app web in PHP where I submit a set of invoices. This processing is done according to the due date. As some days take longer to finish than others, it may occur timeout.

For being a legacy system, I can’t increase the maximum running time any longer (set_time_limit).

When this occurs, I display the generic message of "Processing error", which does not make it clear to the user that the problem was very long execution time.

How can I control to display a message different in case of timeout?
Ideally in Javascript, would be possible?

Answer 1

Call via AJAX the PHP file that does this processing, and then scan the response’s HTTP status code to see if it occurred timeout:

$.ajax({
    type: 'GET',
    url: 'processamento.php',
    cache: false,
    dataType: 'json',
    success: function(response) {
        // código normal
    },
    error: function(error) {
        if (error.status == '408' || error.status == '504') {
            alert('Tempo esgotado! Processamento tomou mais tempo do que o permitido');
        }
    }
});

---

Just illustrating, the code 408 indicates that the server is processing the request for a long time, while the 504 indicates that there may be error or non-existence of the server.

Answer 2

The ideal would be for you to place these invoices in a queue and process them asynchronously.

But as it is a legacy system and maybe you can not make this change, to capture the timeout error you can work with the function register_shutdown_function.

Following example:

<?php
ini_set("display_errors", "0"); // ocultando mensagens de erro
set_time_limit(3); // setando tempo máximo de execução para 3 segundos

class Fatura {    
    public function __construct() {
        // registrando função que vai ser chamada quando o script for finalizado (com sucesso ou não)
        register_shutdown_function(array($this, 'shutdown'));
    }

    private function shutdown() {
        $error = error_get_last();
        if ($error !== null) { // verificando se ocorreu algum erro durante a execução
            $message = $error["message"];
            if (strpos($message, "Maximum execution time") !== false) {
                die(json_encode(array("success" => false, "msg" => "Tempo máximo de execução foi excedido.")));
            }

            die(json_encode(array("success" => false, "msg" => "Desculpe, não foi possível finalizar o processamento.")));
        }
    }

    public function gerar() {
        for ($i = 0; $i < 1000000; $i++) {
            echo "Gerando fatura $i<br/>";
            sleep(1);
        } 
        die(json_encode(array("success" => true)));
    }
}

$fatura = new Fatura();
$fatura->gerar();