How to use "PHP Parallel" with DOMDocument in my following PHP Code? - php

Question

I would like to use PHP-8 Parallel (https://github.com/krakjoe/parallel. Or: https://php.net/parallel) in my function follow_links:
function get_details($url) {
libxml_use_internal_errors(true);
$parser = new DOMDocument();
$parser->loadHTMLFile($url);
// Create an array of all of the title tags.
$title = $parser->getElementsByTagName("title");
// There should only be one <title> on each page, so our array should have only 1 element.
$title = $title->item(0)->nodeValue;
// Give $description and $keywords no value initially. We do this to prevent errors.
$description = "";
$keywords = "";
// Create an array of all of the pages <meta> tags. There will probably be lots of these.
$metas = $parser->getElementsByTagName("meta");
// Loop through all of the <meta> tags we find.
for ($i = 0; $i < $metas->length; $i++) {
$meta = $metas->item($i);
// Get the description
if (strtolower($meta->getAttribute("name")) == "description")
$description = $meta->getAttribute("content");
}
}
function follow_links($url) {
global $already_crawled;
global $crawling;
libxml_use_internal_errors(true);
$parser = new DOMDocument();
$linklist = $parser->getElementsByTagName("a");
foreach ($linklist as $link) {
$l = $link->getAttribute("href");
if (!in_array($l, $already_crawled)) {
$already_crawled[] = $l;
$crawling[] = $l;
// Output the page title, descriptions, keywords and URL. This output is
// piped off to an external file using the command line.
echo get_details($l)."\n";
}
}
// Remove an item from the array after we have crawled it.
// This prevents infinitely crawling the same page.
array_shift($crawling);
foreach ($crawling as $site) {
follow_links($site);
}
}
$starts = ["https://website1.dn", "https://website2.dn", "https://website3.dn", "https://website4.dn"];
follow_links($starts);
I therefore seek to process all the URLs stored in the variable $starts at the same time in a parallel way in follow_links function knowing that it is the function get_details (using DOMDocument) which retrieves the data of each URL ???
Thank you for helping me.