Search the blog

Making nice URLs is a given now. Here’s how to make a nice-looking slug from any string. It should work well on any latin-based character sets. I personally like slugs all lowercase and with hyphens instead of underscores so that’s exactly what this function does. I’ve commented each part so that should be explanation enough.

function generateSlug($value) {

    // Convert all dashes to hyphens
    $value = str_replace('—', '-', $value);
    $value = str_replace('‒', '-', $value);
    $value = str_replace('―', '-', $value);

    // Convert underscores and spaces to hyphens
    $value = str_replace('_', '-', $value);
    $value = str_replace(' ', '-', $value);
    // Convert all accented latin-1 supplement characters to their non-accented counterparts
    // Characters are taken from
    $accents   = array('À', 'Á', 'Â', 'Ã', 'Ä', 'Å', 'Æ',  'Ç', 'È', 'É', 'Ê', 'Ë', 'Ì', 'Í', 'Î', 'Ï', 'Ð', 'Ñ', 'Ò', 'Ó', 'Ô', 'Õ', 'Ö', 'Ø', 'Ù', 'Ú', 'Û', 'Ü', 'Ý', 'ß', 'à', 'á', 'â', 'ã', 'ä', 'å', 'æ',  'ç', 'è', 'é', 'ê', 'ë', 'ì', 'í', 'î', 'ï', 'ð', 'ñ', 'ò', 'ó', 'ô', 'õ', 'ö', 'ø', 'ù', 'ú', 'û', 'ü', 'ý', 'þ', 'ÿ');
    $noAccents = array('A', 'A', 'A', 'A', 'A', 'A', 'AE', 'C', 'E', 'E', 'E', 'E', 'I', 'I', 'I', 'I', 'D', 'N', 'O', 'O', 'O', 'O', 'O', 'O', 'U', 'U', 'U', 'U', 'Y', 'B', 'a', 'a', 'a', 'a', 'a', 'a', 'ae', 'c', 'e', 'e', 'e', 'e', 'i', 'i', 'i', 'i', 'o', 'n', 'o', 'o', 'o', 'o', 'o', 'o', 'u', 'u', 'u', 'u', 'y', 'p', 'y');
    $value = str_replace($accents, $noAccents, $value);

    // Remove everything except 0-9, a-z, A-Z and hyphens
    $value = preg_replace('/[^A-Za-z0-9-]+/', '', $value);
    // Make lowercase - no need for this to be multibyte since there are only 0-9, a-z, A-Z and hyphens left in the string 
    $value = strtolower($value);
    // Only allow single hyphens
    do {
        $value = str_replace('--', '-', $value);
    while (mb_substr_count($value, '--') > 0);
    return $value;


// Test with em dash, double spaces and accented character
echo generateSlug('NEW BLOG:  I just ate at this great café — a good time was had by all!');

// Outputs: new-blog-i-just-ate-at-this-great-cafe-a-good-time-was-had-by-all
Tim Bennett is a web designer and developer. He has a First Class Honours degree in Computing from Leeds Metropolitan University and currently runs his own one-man web design company, Texelate.