Find specific domain name and append url in string PHP

Question

Let's say I have the following string:

<?php
    $str = 'To subscribe go to <a href="http://foo.com/subscribe">Here</a>';
?>

What I'm trying to do is find the URLS within the string that have a specific domain name, "foo.com" for this example, then append the url.

What I want to accomplish:

<?php
    $str = 'To subscribe go to <a href="http://foo.com/subscribe?package=2">Here</a>';
?>

If the domain name in the urls isn't foo.com, I don't want them to be appended.

Answer 1

You can use parse_url() function and the DomDoccument class of php to manipulate the urls, like this:

$str = 'To subscribe go to <a href="http://foo.com/subscribe">Here</a>';

$dom = new DomDocument();
$dom->loadHTML($str);
$urls = $dom->getElementsByTagName('a');

foreach ($urls as $url) {
    $href = $url->getAttribute('href');
    $components = parse_url($href);
    if($components['host'] == "foo.com"){
        $components['path'] .= "?package=2";
        $url->setAttribute('href', $components['scheme'] . "://" . $components['host'] . $components['path']);
    }
    $str = $dom->saveHtml();
}
echo $str;

Output:

To subscribe go to [Here]
                     ^ href="http://foo.com/subscribe?package=2"

Here are the references:

• The DOMDocument class
• parse_url()