Do I need to use "readonly" in "FetchTask.php" when "main.php" contains several "$urls" in my case ???

[chegmarco1989]

Hello.

I have a blocking function named getDetails that gets contents from different urls.

So, here is my main.php code:

<?php

require __DIR__ . '/../vendor/autoload.php';

use Amp\Future;
use Amp\Parallel\Worker;
use function Amp\async;

$urls = [
    'https://website1.net',
    'https://website2.org',
    'https://website3.com',
];

$executions = [];
foreach ($urls as $url) {
    // FetchTask is just an example, you'll have to implement
    // the Task interface for your task.
    $executions[$url] = Worker\submit(new FetchTask($url));
}

// Each submission returns an Execution instance to allow two-way
// communication with a task. Here we're only interested in the
// task result, so we use the Future from Execution::getFuture()
$responses = Future\await(array_map(
    fn (Worker\Execution $e) => $e->getFuture(),
    $executions,
));

foreach ($responses as $url => $response) {
    \printf("Read %d bytes from %s\n", \strlen($response), $url);
}

When that FetchTask.php file should contain:

use Amp\Cancellation;
use Amp\Parallel\Worker\Task;
use Amp\Sync\Channel;

class FetchTask implements Task
{
    public function __construct(
        private readonly string $url,
    ) {
    }

    public function run(Channel $channel, Cancellation $cancellation): string
    {
        return getDetails($this->url); // Example blocking function
    }
}

Does that FetchTask should normally content readonly in its controller knowing that main.php contains several $urls ???

What could be correct FetchTask.php content in case main.php contains several $urls knowing that I use readonly ???

Thanks to answer me.

[trowski]

Your code is creating a new instance of FetchTask for each URL in main.php, so readonly on the constructor is fine. This would be the recommended way to use tasks – a new instance each time you submit a task to a worker.