silverstripe-framework/model/URLSegmentFilter.php

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<?php
/**
* @package framework
* @subpackage model
*/
/**
* Filter certain characters from "URL segments" (also called "slugs"), for nicer (more SEO-friendly) URLs.
* Uses {@link Transliterator} to convert non-ASCII characters to meaningful ASCII representations.
* Use {@link $default_allow_multibyte} to allow a broader range of characters without transliteration.
*
* Caution: Should not be used on full URIs with domains or query parameters.
* In order to retain forward slashes in a path, each individual segment needs to be filtered individually.
*
* See {@link FileNameFilter} for similar implementation for filesystem-based URLs.
*/
class URLSegmentFilter extends Object {
/**
* @var Boolean
*/
static $default_use_transliterator = true;
/**
* @var Array See {@link setReplacements()}.
*/
static $default_replacements = array(
'/&amp;/u' => '-and-',
'/&/u' => '-and-',
'/\s/u' => '-', // remove whitespace
'/_/u' => '-', // underscores to dashes
'/[^A-Za-z0-9+.-]+/u' => '', // remove non-ASCII chars, only allow alphanumeric plus dash and dot
'/[\-]{2,}/u' => '-', // remove duplicate dashes
'/^[\.\-_]/u' => '', // Remove all leading dots, dashes or underscores
);
/**
* Doesn't try to replace or transliterate non-ASCII filters.
* Useful for character sets that have little overlap with ASCII (e.g. far eastern),
* as well as better search engine optimization for URLs.
* @see http://www.ietf.org/rfc/rfc3987
*
* @var boolean
*/
static $default_allow_multibyte = false;
/**
* @var Array See {@link setReplacements()}
*/
public $replacements = array();
/**
* Note: Depending on the applied replacement rules, this method might result in an empty string.
*
* @param String URL path (without domain or query parameters), in utf8 encoding
* @return String A filtered path compatible with RFC 3986
*/
function filter($name) {
if(!$this->getAllowMultibyte()) {
// Only transliterate when no multibyte support is requested
$transliterator = $this->getTransliterator();
if($transliterator) $name = $transliterator->toASCII($name);
}
$name = (function_exists('mb_strtolower')) ? mb_strtolower($name) : strtolower($name);
$replacements = $this->getReplacements();
if($this->getAllowMultibyte()) {
// unset automated removal of non-ASCII characters, and don't try to transliterate
if(isset($replacements['/[^A-Za-z0-9+.-]+/u'])) unset($replacements['/[^A-Za-z0-9+.-]+/u']);
}
foreach($replacements as $regex => $replace) {
$name = preg_replace($regex, $replace, $name);
}
return $name;
}
/**
* @param Array Map of find/replace used for preg_replace().
*/
function setReplacements($r) {
$this->replacements = $r;
}
/**
* @return Array
*/
function getReplacements() {
return ($this->replacements) ? $this->replacements : self::$default_replacements;
}
/**
* @var Transliterator
*/
protected $transliterator;
/**
* @return Transliterator|NULL
*/
function getTransliterator() {
if($this->transliterator === null && self::$default_use_transliterator) {
$this->transliterator = Transliterator::create();
}
return $this->transliterator;
}
/**
* @param Transliterator|FALSE
*/
function setTransliterator($t) {
$this->transliterator = $t;
}
/**
* @var boolean
*/
protected $allowMultibyte;
/**
* @param boolean
*/
function setAllowMultibyte($bool) {
$this->allowMultibyte = $bool;
}
/**
* @return boolean
*/
function getAllowMultibyte() {
return ($this->allowMultibyte !== null) ? $this->allowMultibyte : self::$default_allow_multibyte;
}
}