Can DiDOM be used in a multi-threaded or asynchronous environment?

DiDOM is a PHP library for parsing HTML and working with DOM elements, and it is not inherently designed for multi-threading or asynchronous processing. PHP, traditionally, runs in a single-threaded, synchronous manner, which means that each script runs from start to finish as a single, uninterrupted process. However, there are ways to use DiDOM in environments where multi-threading or asynchronous processing is desired.

Multi-threading with PHP

PHP does not have native multi-threading capabilities like other languages such as Java or C#. However, the pthreads extension allows for multi-threading in PHP by spawning threads that can run in parallel. This extension is not maintained as of PHP 7.2, and the recommended replacement is the parallel extension starting from PHP 7.4.

Here's a simple example of how you might use the parallel extension to scrape multiple URLs concurrently with DiDOM:

<?php
require_once 'vendor/autoload.php';

use parallel\{Runtime, Future};
use DiDom\Document;

function scrapeWebsite($url) {
    $document = new Document($url, true);
    // Your scraping logic here...
    return $document->find('title')[0]->text();
}

$urls = [
    'https://example.com',
    'https://example.org',
    'https://example.net'
];

$runtimes = [];
$futures = [];

foreach ($urls as $url) {
    $runtime = new Runtime();
    $futures[] = $runtime->run('scrapeWebsite', [$url]);
    $runtimes[] = $runtime; // Keep reference so runtime doesn't shut down
}

foreach ($futures as $future) {
    echo $future->value() . PHP_EOL;
}

Asynchronous Processing

Asynchronous processing in PHP can be achieved using libraries like ReactPHP or Amp. These libraries provide a non-blocking event loop that can handle multiple operations concurrently without multi-threading.

Below is an example using ReactPHP and clue/reactphp-buzz for making non-blocking HTTP requests along with DiDOM for parsing the responses:

<?php
require 'vendor/autoload.php';

use Clue\React\Buzz\Browser;
use React\EventLoop\Factory;
use DiDom\Document;

$loop = Factory::create();
$client = new Browser($loop);

$urls = [
    'https://example.com',
    'https://example.org',
    'https://example.net'
];

foreach ($urls as $url) {
    $client->get($url)->then(
        function (Psr\Http\Message\ResponseInterface $response) {
            $document = new Document((string)$response->getBody());
            echo $document->find('title')[0]->text() . PHP_EOL;
        },
        function (Exception $e) {
            echo 'Error: ' . $e->getMessage() . PHP_EOL;
        }
    );
}

$loop->run();

Please note that when using multi-threading or asynchronous processing in PHP, it's essential to consider the thread safety of the libraries you are using. Make sure that the code you are executing in parallel is thread-safe and does not lead to race conditions or other concurrency issues. With external libraries like DiDOM, you should ensure that no shared state can be mutated concurrently across threads or asynchronous tasks.