Question

There are a lot of posts on converting relative to absolute paths in PHP. I’m looking for a specific implementation beyond these posts (hopefully). Could anyone please help me with this specific implementation?

I have a PHP variable containing diverse HTML, including hrefs and imgs containing relative urls. Mostly (for example) /en/discover or /img/icons/facebook.png

I want to process this PHP variable in such a way that the values of my hrefs and imgs will be converted to http://mydomain.com/en/discover and http://mydomain.com/img/icons/facebook.png

I believe the question below covers the solution for hrefs. How can we expand this to also consider imgs?

• Change a relative URL to absolute URL

Would a regex be in order? Or since we’re dealing with a lot of output should we use DOMDocument?

Answer 1

After some further research I’ve stumbled upon this article from Gerd Riesselmann on how to solve the absence of a base href solution for RSS-feeds. His snippet actually solves my question!

http://www.gerd-riesselmann.net/archives/2005/11/rss-doesnt-know-a-base-url

<?php
function relToAbs($text, $base)
{
  if (empty($base))
    return $text;
  // base url needs trailing /
  if (substr($base, -1, 1) != "/")
    $base .= "/";
  // Replace links
  $pattern = "/<a([^>]*) " .
             "href=\"[^http|ftp|https|mailto]([^\"]*)\"/";
  $replace = "<a\${1} href=\"" . $base . "\${2}\"";
  $text = preg_replace($pattern, $replace, $text);
  // Replace images
  $pattern = "/<img([^>]*) " . 
             "src=\"[^http|ftp|https]([^\"]*)\"/";
  $replace = "<img\${1} src=\"" . $base . "\${2}\"";
  $text = preg_replace($pattern, $replace, $text);
  // Done
  return $text;
}
?>

Thank you Gerd! And thank you shadyyx to point me in the direction of base href!