PHP Calling a function on matches in regexp - php

Question

I need to scramble/encode all e-mail addresses in a string, turn them into links and leave the rest of the string intact?
I'm using
$withlinks = preg_replace("/([\w-?&;#~=\.\/]+\#(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,3}|[0-9]{1,3})(\]?))/i","$1",$nolinks);
to make links out of e-mails and
function encode_email($str) {
$str = mb_convert_encoding($str , 'UTF-32', 'UTF-8'); //big endian
$split = str_split($str, 4);
$res = "";
foreach ($split as $c) {
$cur = 0;
for ($i = 0; $i < 4; $i++) {
$cur |= ord($c[$i]) << (8*(3 - $i));
}
$res .= "&#" . $cur . ";";
}
return $res;
}
to encode the addresses but I can't figure out how to put them together, so that only e-mails would be encoded and turned into links.

Answer 1

You can use preg_replace_callback so that you can manipulate the replacement text to be exactly what you want...
<?php
// test string
$nolinks = "amy#winehous.com is an email for bobby#fisher.com plays chess";
// your original function
function encode_email($str)
{
$str = mb_convert_encoding($str, 'UTF-32', 'UTF-8'); //big endian
$split = str_split($str, 4);
$res = "";
foreach ($split as $c) {
$cur = 0;
for ($i = 0; $i < 4; $i++) {
$cur |= ord($c[$i]) << (8 * (3 - $i));
}
$res .= "&#" . $cur . ";";
}
return $res;
}
// function used for callback
function encode_email_and_add_link($in)
{
// get encoded email address (don't actually know what this function does)
$encoded = encode_email($in[1]);
// return a hyperlink string built with encoded email address
return "$encoded";
}
// do the regex with callback
$withlinks = preg_replace_callback("/([\w-?&;#~=\.\/]+\#(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,3}|[0-9]{1,3})(\]?))/i", 'encode_email_and_add_link', $nolinks);
// output the results
echo $withlinks;