Dirify in PHP

Movable Type has a dirify option that converts strings to something that can be used in a Web filename. It strips certain characters, converts spaces to underscores, and makes some other changes. One of my client sites has a number of pages that use PHP to access the MT database directly and displays the entries dynamically (something that the upcoming MT 3.1 does natively).

But since the site uses static pages with dirified titles as the filenames, I needed to convert the MT data from the database to MT’s archive URL format using a dirify function, so I ported the dirify mechanism to PHP.

<?php
function dirify($s) {
     $s = convert_high_ascii($s);  ## convert high-ASCII chars to 7bit.
     $s = strtolower($s);           ## lower-case.
     $s = strip_tags($s);       ## remove HTML tags.
     $s = preg_replace('!&[^;\s]+;!','',$s);         ## remove HTML entities.
     $s = preg_replace('![^\w\s]!','',$s);           ## remove non-word/space chars.
     $s = preg_replace('!\s+!','_',$s);               ## change space chars to underscores.
     return $s;    
}

function convert_high_ascii($s) {
 	$HighASCII = array(
 		"!\xc0!" => 'A',    # A`
 		"!\xe0!" => 'a',    # a`
 		"!\xc1!" => 'A',    # A'
 		"!\xe1!" => 'a',    # a'
 		"!\xc2!" => 'A',    # A^
 		"!\xe2!" => 'a',    # a^
 		"!\xc4!" => 'Ae',   # A:
 		"!\xe4!" => 'ae',   # a:
 		"!\xc3!" => 'A',    # A~
 		"!\xe3!" => 'a',    # a~
 		"!\xc8!" => 'E',    # E`
 		"!\xe8!" => 'e',    # e`
 		"!\xc9!" => 'E',    # E'
 		"!\xe9!" => 'e',    # e'
 		"!\xca!" => 'E',    # E^
 		"!\xea!" => 'e',    # e^
 		"!\xcb!" => 'Ee',   # E:
 		"!\xeb!" => 'ee',   # e:
 		"!\xcc!" => 'I',    # I`
 		"!\xec!" => 'i',    # i`
 		"!\xcd!" => 'I',    # I'
 		"!\xed!" => 'i',    # i'
 		"!\xce!" => 'I',    # I^
 		"!\xee!" => 'i',    # i^
 		"!\xcf!" => 'Ie',   # I:
 		"!\xef!" => 'ie',   # i:
 		"!\xd2!" => 'O',    # O`
 		"!\xf2!" => 'o',    # o`
 		"!\xd3!" => 'O',    # O'
 		"!\xf3!" => 'o',    # o'
 		"!\xd4!" => 'O',    # O^
 		"!\xf4!" => 'o',    # o^
 		"!\xd6!" => 'Oe',   # O:
 		"!\xf6!" => 'oe',   # o:
 		"!\xd5!" => 'O',    # O~
 		"!\xf5!" => 'o',    # o~
 		"!\xd8!" => 'Oe',   # O/
 		"!\xf8!" => 'oe',   # o/
 		"!\xd9!" => 'U',    # U`
 		"!\xf9!" => 'u',    # u`
 		"!\xda!" => 'U',    # U'
 		"!\xfa!" => 'u',    # u'
 		"!\xdb!" => 'U',    # U^
 		"!\xfb!" => 'u',    # u^
 		"!\xdc!" => 'Ue',   # U:
 		"!\xfc!" => 'ue',   # u:
 		"!\xc7!" => 'C',    # ,C
 		"!\xe7!" => 'c',    # ,c
 		"!\xd1!" => 'N',    # N~
 		"!\xf1!" => 'n',    # n~
 		"!\xdf!" => 'ss'
 	);
 	$find = array_keys($HighASCII);
 	$replace = array_values($HighASCII);
 	$s = preg_replace($find,$replace,$s);
     return $s;
}
?>

To use this function, simply pass in the string you want dirified, like so:

<?php echo dirify("Here’s the title of an entry!"); ?>