Php parse links/emails

Question

Hello,

I am wondering if there is a simple snippet which converts links of any kind:

http://www.cnn.com to <a href="http://www.cnn.com"&gt;http://www.cnn.com&lt;/a&gt;
cnn.com to <a href="http://www.cnn.com"&gt;cnn.com&lt;/a&gt;
www.cnn.com to <a href="http://www.cnn.com"&gt;www.cnn.com&lt;/a&gt;
[email protected] to  to <a href="mailto:mailto:[email protected]">mailto:[email protected]</a>

I do not want to use any PHP5 specific library.

Thank you for your time.

UPDATE I have updated the above text to what i want to convert it to. Please note that the href tag and the text are different for case 2 and 3.

UPDATE2 Hows does gmail chat do it? Theirs is pretty smart and works only for real domains names. e.g. a.ly works but a.cb does not work.

Answer 1

Here's the email snippet:

$email = "[email protected]";

$pos = strrpos($email, "@");
if (!$pos === false) {
    // This is an email address!
    $email .= "mailto:" . $email;
}

What exactly are you looking to do with the links? strip the www or http? or add http://www to any link if required?

Answer 2

yes , http://www.gidforums.com/t-1816.html

<?php
/**
   NAME        : autolink()
   VERSION     : 1.0
   AUTHOR      : J de Silva
   DESCRIPTION : returns VOID; handles converting
                 URLs into clickable links off a string.
   TYPE        : functions
   ======================================*/

function autolink( &$text, $target='_blank', $nofollow=true )
{
  // grab anything that looks like a URL...
  $urls  =  _autolink_find_URLS( $text );
  if( !empty($urls) ) // i.e. there were some URLS found in the text
  {
    array_walk( $urls, '_autolink_create_html_tags', array('target'=>$target, 'nofollow'=>$nofollow) );
    $text  =  strtr( $text, $urls );
  }
}

function _autolink_find_URLS( $text )
{
  // build the patterns
  $scheme         =       '(http:\/\/|https:\/\/)';
  $www            =       'www\.';
  $ip             =       '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}';
  $subdomain      =       '[-a-z0-9_]+\.';
  $name           =       '[a-z][-a-z0-9]+\.';
  $tld            =       '[a-z]+(\.[a-z]{2,2})?';
  $the_rest       =       '\/?[a-z0-9._\/~#&=;%+?-]+[a-z0-9\/#=?]{1,1}';            
  $pattern        =       "$scheme?(?(1)($ip|($subdomain)?$name$tld)|($www$name$tld))$the_rest";

  $pattern        =       '/'.$pattern.'/is';
  $c              =       preg_match_all( $pattern, $text, $m );
  unset( $text, $scheme, $www, $ip, $subdomain, $name, $tld, $the_rest, $pattern );
  if( $c )
  {
    return( array_flip($m[0]) );
  }
  return( array() );
}

function _autolink_create_html_tags( &$value, $key, $other=null )
{
  $target = $nofollow = null;
  if( is_array($other) )
  {
    $target      =  ( $other['target']   ? " target=\"$other[target]\"" : null );
    // see: http://www.google.com/googleblog/2005/01/preventing-comment-spam.html
    $nofollow    =  ( $other['nofollow'] ? ' rel="nofollow"'            : null );     
  }
  $value = "<a href=\"$key\"$target$nofollow>$key</a>";
} 

?>