Question

I need to catch custom “tag” in text string, rewrite and replace it.
It looks like:

<mytag=http://url.com/file.php?some=variable&another=variable>

First I need to catch url from tag, then I rewrite it with my function and then replace whole tag with new url. Can anybody help me how to catch and replace it? In text can be more tags with various url’s.

Answer 1

That’s trivial. You have enough context and anchors for that. And basically using preg_replace or preg_repace_callback (for more complex replacement schemes) works as follows:

$src = preg_replace('~  <mytag=  (http://[^>]+)  >  ~smix', '<a href=$1>$1</a>', $src);

The whitespace here are decorative. Crucial is the [^>] for not matching to much, and ( and ) for capturing the URL as $1.

• See also Open source RegexBuddy alternatives and Online regex testing for some helpful tools, or RegExp.info for a nicer tutorial.