Change a relative URL to absolute URL - php

Question

for example i've got a string like this:
$html = '
test
test
test
hi
';
and i want to append the absolute url to all hrefs where no abolute domain is given.
$html = '
test
test
test
hi
';
whats the best way to do that? i guess something with RegEx, but my RegEx skills are ** ;)
thanks in advance!

Answer 1

found a good way :
$html = preg_replace("#(<\s*a\s+[^>]*href\s*=\s*[\"'])(?!http)([^\"'>]+)([\"'>]+)#", '$1http://mydomain.com/$2$3', $html);
you can use (?!http|mailto) if you have also mailto links in your $html

Answer 2

$domain = 'http://mydomain';
preg_match_all('/href\="(.*?)"/im', $html, $matches);
foreach($matches[1] as $n=>$link) {
if(substr($link, 0, 4) != 'http')
$html = str_replace($matches[1][$n], $domain . $matches[1][$n], $html);
}

Answer 3

The previous answer will cause problems with your first and fourth example because it fails to include a forward slash to separate the page from the page name. Admittedly this can be fixed by simply appending it to the $domain, but if you do that then href="/something.php" will end up with two.
Just to give an alternative Regex solution you could go with something like this...
$pattern = '#'#(?<=href=")(.+?)(?=")#'';
$output = preg_replace_callback($pattern, 'make_absolute', $input);
function make_absolute($link) {
$domain = 'http://domain.com';
if(strpos($link[1], 'http')!==0) {
if(strpos($link[1], '/')!==0) {
return $domain.'/'.$link[1];
} else {
return $domain.$link[1];
}
}
return $link[1];
}
However it is worth noting that with a link such as href="example.html" the link is relative to the current directory neither method shown so far will work correctly for relative links that aren't in the root directory. In order to provide a solution that is though more information would be required about where the information came from.