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Definition

From Wikipedia:

A slug is the part of a URL which identifies a page using human-readable keywords.

To make the URL easier for users to type, special characters are often removed or replaced as well. For instance, accented characters are usually replaced by letters from the English alphabet; punctuation marks are generally removed; and spaces (which have to be encoded as %20 or +) are replaced by dashes (-) or underscores (_), which are more aesthetically pleasing.

Context

I developed a photo-sharing website on which users can upload, share and view photos.

All pages are generated automatically without my grip on the title. Because the title of a photo or the name of a user may contain accented characters or spaces, I needed a function to automatically create slugs and keep readable URLs.

I created the following function which replaces accented chara开发者_如何学Pythoncters (âèêëçî), removes punctuation and bad characters (#@&~^!) and transforms spaces in dashes.

Questions

• What do you think about this function?
• Do you know any other functions to create slugs?

Code

php:

function sluggable($str) {

    $before = array(
        'àáâãäåòóôõöøèéêëðçìíîïùúûüñšž',
        '/[^a-z0-9\s]/',
        array('/\s/', '/--+/', '/---+/')
    );
 
    $after = array(
        'aaaaaaooooooeeeeeciiiiuuuunsz',
        '',
        '-'
    );

    $str = strtolower($str);
    $str = strtr($str, $before[0], $after[0]);
    $str = preg_replace($before[1], $after[1], $str);
    $str = trim($str);
    $str = preg_replace($before[2], $after[2], $str);
 
    return $str;
}

---

I like the php-slugs code at google code solution. But if you want a simpler one that works with UTF-8:

function format_uri( $string, $separator = '-' )
{
    $accents_regex = '~&([a-z]{1,2})(?:acute|cedil|circ|grave|lig|orn|ring|slash|th|tilde|uml);~i';
    $special_cases = array( '&' => 'and', "'" => '');
    $string = mb_strtolower( trim( $string ), 'UTF-8' );
    $string = str_replace( array_keys($special_cases), array_values( $special_cases), $string );
    $string = preg_replace( $accents_regex, '$1', htmlentities( $string, ENT_QUOTES, 'UTF-8' ) );
    $string = preg_replace("/[^a-z0-9]/u", "$separator", $string);
    $string = preg_replace("/[$separator]+/u", "$separator", $string);
    return $string;
}

So

echo format_uri("#@&~^!âèêëçî");

outputs

-and-aeeeci

---

A few people have linked to "php-slugs" on google.com, but it looks like their page is a little screwy now, so here it is if anyone needs it:

// source: https://code.google.com/archive/p/php-slugs/

function my_str_split($string)
{
    $slen=strlen($string);
    for($i=0; $i<$slen; $i++)
    {
        $sArray[$i]=$string{$i};
    }
    return $sArray;
}

function noDiacritics($string)
{
    //cyrylic transcription
    $cyrylicFrom = array('А', 'Б', 'В', 'Г', 'Д', 'Е', 'Ё', 'Ж', 'З', 'И', 'Й', 'К', 'Л', 'М', 'Н', 'О', 'П', 'Р', 'С', 'Т', 'У', 'Ф', 'Х', 'Ц', 'Ч', 'Ш', 'Щ', 'Ъ', 'Ы', 'Ь', 'Э', 'Ю', 'Я', 'а', 'б', 'в', 'г', 'д', 'е', 'ё', 'ж', 'з', 'и', 'й', 'к', 'л', 'м', 'н', 'о', 'п', 'р', 'с', 'т', 'у', 'ф', 'х', 'ц', 'ч', 'ш', 'щ', 'ъ', 'ы', 'ь', 'э', 'ю', 'я');
    $cyrylicTo   = array('A', 'B', 'W', 'G', 'D', 'Ie', 'Io', 'Z', 'Z', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'R', 'S', 'T', 'U', 'F', 'Ch', 'C', 'Tch', 'Sh', 'Shtch', '', 'Y', '', 'E', 'Iu', 'Ia', 'a', 'b', 'w', 'g', 'd', 'ie', 'io', 'z', 'z', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'r', 's', 't', 'u', 'f', 'ch', 'c', 'tch', 'sh', 'shtch', '', 'y', '', 'e', 'iu', 'ia'); 


    $from = array("Á", "À", "Â", "Ä", "Ă", "Ā", "Ã", "Å", "Ą", "Æ", "Ć", "Ċ", "Ĉ", "Č", "Ç", "Ď", "Đ", "Ð", "É", "È", "Ė", "Ê", "Ë", "Ě", "Ē", "Ę", "Ə", "Ġ", "Ĝ", "Ğ", "Ģ", "á", "à", "â", "ä", "ă", "ā", "ã", "å", "ą", "æ", "ć", "ċ", "ĉ", "č", "ç", "ď", "đ", "ð", "é", "è", "ė", "ê", "ë", "ě", "ē", "ę", "ə", "ġ", "ĝ", "ğ", "ģ", "Ĥ", "Ħ", "I", "Í", "Ì", "İ", "Î", "Ï", "Ī", "Į", "IJ", "Ĵ", "Ķ", "Ļ", "Ł", "Ń", "Ň", "Ñ", "Ņ", "Ó", "Ò", "Ô", "Ö", "Õ", "Ő", "Ø", "Ơ", "Œ", "ĥ", "ħ", "ı", "í", "ì", "i", "î", "ï", "ī", "į", "ij", "ĵ", "ķ", "ļ", "ł", "ń", "ň", "ñ", "ņ", "ó", "ò", "ô", "ö", "õ", "ő", "ø", "ơ", "œ", "Ŕ", "Ř", "Ś", "Ŝ", "Š", "Ş", "Ť", "Ţ", "Þ", "Ú", "Ù", "Û", "Ü", "Ŭ", "Ū", "Ů", "Ų", "Ű", "Ư", "Ŵ", "Ý", "Ŷ", "Ÿ", "Ź", "Ż", "Ž", "ŕ", "ř", "ś", "ŝ", "š", "ş", "ß", "ť", "ţ", "þ", "ú", "ù", "û", "ü", "ŭ", "ū", "ů", "ų", "ű", "ư", "ŵ", "ý", "ŷ", "ÿ", "ź", "ż", "ž");
    $to   = array("A", "A", "A", "AE", "A", "A", "A", "A", "A", "AE", "C", "C", "C", "C", "C", "D", "D", "D", "E", "E", "E", "E", "E", "E", "E", "E", "G", "G", "G", "G", "G", "a", "a", "a", "ae", "ae", "a", "a", "a", "a", "ae", "c", "c", "c", "c", "c", "d", "d", "d", "e", "e", "e", "e", "e", "e", "e", "e", "g", "g", "g", "g", "g", "H", "H", "I", "I", "I", "I", "I", "I", "I", "I", "IJ", "J", "K", "L", "L", "N", "N", "N", "N", "O", "O", "O", "OE", "O", "O", "O", "O", "CE", "h", "h", "i", "i", "i", "i", "i", "i", "i", "i", "ij", "j", "k", "l", "l", "n", "n", "n", "n", "o", "o", "o", "oe", "o", "o", "o", "o", "o", "R", "R", "S", "S", "S", "S", "T", "T", "T", "U", "U", "U", "UE", "U", "U", "U", "U", "U", "U", "W", "Y", "Y", "Y", "Z", "Z", "Z", "r", "r", "s", "s", "s", "s", "ss", "t", "t", "b", "u", "u", "u", "ue", "u", "u", "u", "u", "u", "u", "w", "y", "y", "y", "z", "z", "z");


    $from = array_merge($from, $cyrylicFrom);
    $to   = array_merge($to, $cyrylicTo);

    $newstring=str_replace($from, $to, $string);
    return $newstring;
}

function makeSlugs($string, $maxlen=0)
{
    $newStringTab=array();
    $string=strtolower(noDiacritics($string));
    if(function_exists('str_split'))
    {
        $stringTab=str_split($string);
    }
    else
    {
        $stringTab=my_str_split($string);
    }

    $numbers=array("0","1","2","3","4","5","6","7","8","9","-");
    //$numbers=array("0","1","2","3","4","5","6","7","8","9");

    foreach($stringTab as $letter)
    {
        if(in_array($letter, range("a", "z")) || in_array($letter, $numbers))
        {
            $newStringTab[]=$letter;
        }
        elseif($letter==" ")
        {
            $newStringTab[]="-";
        }
    }

    if(count($newStringTab))
    {
        $newString=implode($newStringTab);
        if($maxlen>0)
        {
            $newString=substr($newString, 0, $maxlen);
        }

        $newString = removeDuplicates('--', '-', $newString);
    }
    else
    {
        $newString='';
    }

    return $newString;
}


function checkSlug($sSlug)
{
    if(preg_match("/^[a-zA-Z0-9]+[a-zA-Z0-9\-]*$/", $sSlug) == 1)
    {
        return true;
    }

    return false;
}

function removeDuplicates($sSearch, $sReplace, $sSubject)
{
    $i=0;
    do{

        $sSubject=str_replace($sSearch, $sReplace, $sSubject);
        $pos=strpos($sSubject, $sSearch);

        $i++;
        if($i>100)
        {
            die('removeDuplicates() loop error');
        }

    }while($pos!==false);

    return $sSubject;
}

---

    setlocale(LC_ALL, 'en_US.UTF8');

        function slugify($text)
        {
          // replace non letter or digits by -
          $text = preg_replace('~[^\\pL\d]+~u', '-', $text);

          // trim
          $text = trim($text, '-');

          // transliterate
          $text = iconv('utf-8', 'us-ascii//TRANSLIT', $text);

          // lowercase
          $text = strtolower($text);

          // remove unwanted characters
          $text = preg_replace('~[^-\w]+~', '', $text);

          if (empty($text))
          {
            return 'n-a';
          }

          return $text;
        }


$slug = slugify($var);

---

I found this on the net, does exactly as you want, but keeps the case.

function sluggable($p) {
    $ts = array("/[À-Å]/","/Æ/","/Ç/","/[È-Ë]/","/[Ì-Ï]/","/Ð/","/Ñ/","/[Ò-ÖØ]/","/×/","/[Ù-Ü]/","/[Ý-ß]/","/[à-å]/","/æ/","/ç/","/[è-ë]/","/[ì-ï]/","/ð/","/ñ/","/[ò-öø]/","/÷/","/[ù-ü]/","/[ý-ÿ]/");
    $tn = array("A","AE","C","E","I","D","N","O","X","U","Y","a","ae","c","e","i","d","n","o","x","u","y");
    return preg_replace($ts,$tn, $p);
}

source

---

This really works fine. Returns correct clean url slug.

$string = '(1234) S*m@#ith S)&+*t `E}{xam)ple?>land   - - 1!_2)#3)(*4""5';

// remove all non alphanumeric characters except spaces
$clean =  preg_replace('/[^a-zA-Z0-9\s]/', '', strtolower($string)); 

// replace one or multiple spaces into single dash (-)
$clean =  preg_replace('!\s+!', '-', $clean); 

echo $clean; // 1234-smith-st-exampleland-12345

---

function seourl($phrase, $maxLength = 100000000000000) {
        $result = strtolower($phrase);

        $result = preg_replace("~[^A-Za-z0-9-\s]~", "", $result);
        $result = trim(preg_replace("~[\s-]+~", " ", $result));
        $result = trim(substr($result, 0, $maxLength));
        $result = preg_replace("~\s~", "-", $result);

        return $result;
    }

---

function remove_accents($string)
{
    $a = 'ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõöøùúûýýþÿŔŕ';
    $b = 'aaaaaaaceeeeiiiidnoooooouuuuybsaaaaaaaceeeeiiiidnoooooouuuyybyRr';
    $string = strtr(utf8_decode($string), utf8_decode($a), $b);
    return utf8_encode($string);
}

function format_slug($title)
{
    $title = remove_accents($title);
    $title = trim(strtolower($title));
    $title = preg_replace('#[^a-z0-9\\-/]#i', '_', $title);
    return trim(preg_replace('/-+/', '-', $title), '-/');
}

use : echo format_slug($var);

---

This is the class we use and while it can perform individual operations, it also has the ability to turn strings (or paths) into slug versions (only a-z, 0-9, and - are in the final output). It also does a couple extra things such as convert ampersands (&) to the word and.

Usage:

echo (new Str('My Cover Letter & Résumé'))->slugify()->__toString();

my-cover-letter-and-resume

Str class:

<?php

use RuntimeException;
use Transliterator;

class Str
{
    /**
     * Will hold an instance of Transliterator
     * for removing accents from characters.
     * Same instance for all instances of this class is fine.
     */
    private static $accent_transliterator;
    private $string;

    public function __construct(string $string)
    {
        $this->string = $string;
    }

    public function __toString()
    {
        return $this->string;
    }

    public function cleanForUrlPath(): self
    {
        $path = '';

        // Loop through path sections (separated by `/`)
        // and slugify each section.
        foreach (explode('/', $this->string) as $section) {
            $section = (new static($section))->slugify()->__toString();
            if ($section !== '') {
                $path .= "/$section";
            }
        }

        // Save the cleaned path
        $this->string = "$path/";

        return $this;
    }

    public function cleanUpSlugDashes(): self
    {
        // Remove extra dashes
        $this->string = preg_replace('/--+/', '-', $this->string);

        // Remove leading and trailing dashes
        $this->string = trim($this->string, '-');

        return $this;
    }

    /**
     * Replace symbols with word replacements.
     * Eg, `&` becomes ` and `.
     */
    public function convertSymbolsToWords(): self
    {
        $this->string = strtr($this->string, [
            '@' => ' at ',
            '%' => ' percent ',
            '&' => ' and ',
        ]);

        return $this;
    }

    public static function getSpacerCharacters(
        array $with = [],
        array $without = []
    ): array {
        return array_unique(array_diff(array_merge([
            ' ', // space
            '…', // ellipsis
            '–', // en dash
            '—', // em dash
            '/', // slash
            '\\', // backslash
            ':', // colon
            ';', // semi-colon
            '.', // period
            '+', // plus sign
            '#', // pound sign
            '~', // tilde
            '_', // underscore
            '|', // pipe
        ], array_values($with)), array_values($without)));
    }

    public function lower(): self
    {
        $this->string = strtolower($this->string);

        return $this;
    }

    /**
     * Replaces all accented characters
     * with similar ASCII characters.
     */
    public function removeAccents(): self
    {
        // If no accented characters are found,
        // return the given string as-is.
        if (!preg_match('/[\x80-\xff]/', $this->string)) {
            return $this;
        }

        // Instantiate Transliterator if we haven't already
        if (!isset(self::$accent_transliterator)) {
            self::$accent_transliterator = Transliterator::create(
                'Any-Latin; Latin-ASCII;'
            );

            if (self::$accent_transliterator === null) {
                // @codeCoverageIgnoreStart
                throw new RuntimeException(
                    'Could not create a transliterator'
                );
                // @codeCoverageIgnoreEnd
            }
        }

        // Save transliterated string
        $this->string = (self::$accent_transliterator)->transliterate(
            $this->string
        );

        return $this;
    }

    public function replace($search, $replace)
    {
        $this->string = str_replace($search, $replace, $this->string);

        return $this;
    }

    public function replaceRegex($pattern, $replacement): self
    {
        $this->string = preg_replace($pattern, $replacement, $this->string);

        return $this;
    }

    /**
     * @param int $length number of bytes to shorten the string to
     */
    public function shorten(int $length): self
    {
        // If the string is already `$length` or shorter,
        // return it as-is.
        if (strlen($this->string) <= $length) {
            return $this;
        }

        // Shorten by 2 additional characters
        // to account for the three periods that are appended.
        // Only need to shorten by 2
        // as there's always at least one character (space) removed
        // when the last word is popped off of the array.
        $length -= 2;

        // Shorten the string to `$length` and split into words
        $words = explode(' ', substr($this->string, 0, $length));

        // Discard the last word as it's a partial word,
        // or empty if the last character happened to be a space.
        // If there's only one word,
        // then it was longer than `$length`
        // and the truncated version should be returned.
        if (count($words) > 1) {
            array_pop($words);
        }

        // Save the shortened string with "..." appended
        $this->string = rtrim(implode(' ', $words), ':').'...';

        return $this;
    }

    public function slugify(): self
    {
        // If the string is already a slug
        if (preg_match('/^[a-z0-9\\-]+$/', $this->string)) {
            return $this;
        }

        // - Normalize accents
        // - Normalize symbols
        // - Lowercase
        // - Replace space characters with dashes
        // - Remove non-slug characters
        // - Clean up leading, trailing, and consecutive dashes
        return $this
            ->removeAccents()
            ->convertSymbolsToWords()
            ->lower()
            ->spacersToDashes()
            ->replaceRegex('/([^a-z0-9\\-]+)/', '')
            ->cleanUpSlugDashes();
    }

    public function spacersToDashes(): self
    {
        return $this->replace(static::getSpacerCharacters(), '-');
    }
}