Run PHP function asynchronously

Question

Using PHP, it is possible to run a function asynchronously?

Example:

The client(browser) makes a request to the server, in this request PHP executes an asynchronous function that may take a few seconds, but before it finishes, the server responds to the client so that while the asynchronous operation is being executed, the browser does not need to wait for it to end to receive a response.

Answer 1

Yes, from some external libraries it is possible to implement similar things quite simply.

The best known project is the reactPHP.

There is a very interesting benchmark comparing the reactPHP with nodejs.

Answer 2

You can get this result using parallelism with the PHP extension Gearman

Example:

<?php
# Criação do worker
$gmworker= new GearmanWorker();

# Adicionando um servidor (localhost é o padrão)
$gmworker->addServer();

# Registre uma função
$gmworker->addFunction("reverse", "reverse_fn");

print "Esperando resultado...\n";

while($gmworker->work())
{
  if ($gmworker->returnCode() != GEARMAN_SUCCESS)
  {
    echo "return_code: " . $gmworker->returnCode() . "\n";
    break;
  } else {
    print "Ainda esperando resultado...\n";
  }
}

function reverse_fn($job)
{
  return strrev($job->workload());
}

Behold more examples in the PHP manual.

Answer 3

In complento the two answers above, you can use German + reactPhp with the gearman-async: "A async Gearman implementation for PHP ontop of reactphp"

Example of use:

<?php

use Gearman\Async\ClientInterface;
use Gearman\Async\Event\TaskDataEvent;
use Gearman\Async\TaskInterface;
use Gearman\Async\Factory;

require_once __DIR__ . "/../vendor/autoload.php";

// use default options
$factory = new Factory();

$factory->createClient("127.0.0.1", 4730)->then(
    // on successful creation
    function (ClientInterface $client) {
        $client->submit("reverse", "Hallo Welt!")->then(function(TaskInterface $task) {
            printf("Submitted: %s with \"%s\" [handle: %s]\n", 
                $task->getFunction(), 
                $task->getWorkload(), 
                $task->getHandle()
            );

            $task->on('complete', function (TaskDataEvent $event, ClientInterface $client) {
                echo "Result: {$event->getData()}\n";
                $client->disconnect();
            });
        });
    },
    // error-handler
    function($error) {
        echo "Error: $error\n";
    }
);

$factory->getEventLoop()->run();