Question

When a user enters a URL, e.g. http://www.google.com, I would like to be able to parse that text using PHP, find any links, and replace them with <a> tags that include the original URL as an HREF.

In other words, http://www.google.com will become

<a href="http://www.google.com">http://www.google.com</a>

I’d like to be able to do this for all URLs of these forms (with .com interchangeable with any TLD):

http://www.google.com
www.google.com
google.com
docs.google.com

What’s the most performant way to do this? I could try writing some really fancy regex, but I doubt that’s the best method available to me.

For bonus points, I’d also like to prepend http:// to any URL lacking it, and strip the display text itself down to something of the form http://www.google.com/reallyLongL... and display an external link icon afterwards.

Answer 1

I got this working exactly the way I want here:

<?php

$input = <<<EOF
http://www.example.com/
http://example.com
www.example.com
http://iamanextremely.com/long/link/so/I/will/be/trimmed/down/a/bit/so/i/dont/mess
/up/text/wrapping.html
EOF;

  function trimlong($match)
  {
    $url = $match[0];
    $display = $url;
    if ( strlen($display) > 30 ) {
      $display = substr($display,0,30)."...";
    }
    return '<a href="'.$url.'">'.$display.' <img src="http://static.goalscdn.com/img/external-link.gif" height="10" width="11" /></a>';
  }

$output = preg_replace_callback('#(http://|www\\.)[^\\s<]+[^\\s<,.]#i',
                                 array($this,'trimlong'),$input);

echo $output;