Ho provato diversi minificatori e rimuovono troppo poco o troppo.
Questo codice rimuove gli spazi vuoti ridondanti e i tag HTML (finali) opzionali. Inoltre lo gioca in modo sicuro e non rimuove nulla che potrebbe potenzialmente rompere HTML, JS o CSS.
Anche il codice mostra come farlo in Zend Framework:
class Application_Plugin_Minify extends Zend_Controller_Plugin_Abstract {
public function dispatchLoopShutdown() {
$response = $this->getResponse();
$body = $response->getBody(); //actually returns both HEAD and BODY
//remove redundant (white-space) characters
$replace = array(
//remove tabs before and after HTML tags
'/\>[^\S ]+/s' => '>',
'/[^\S ]+\</s' => '<',
//shorten multiple whitespace sequences; keep new-line characters because they matter in JS!!!
'/([\t ])+/s' => ' ',
//remove leading and trailing spaces
'/^([\t ])+/m' => '',
'/([\t ])+$/m' => '',
// remove JS line comments (simple only); do NOT remove lines containing URL (e.g. 'src="http://server.com/"')!!!
'~//[a-zA-Z0-9 ]+$~m' => '',
//remove empty lines (sequence of line-end and white-space characters)
'/[\r\n]+([\t ]?[\r\n]+)+/s' => "\n",
//remove empty lines (between HTML tags); cannot remove just any line-end characters because in inline JS they can matter!
'/\>[\r\n\t ]+\</s' => '><',
//remove "empty" lines containing only JS's block end character; join with next line (e.g. "}\n}\n</script>" --> "}}</script>"
'/}[\r\n\t ]+/s' => '}',
'/}[\r\n\t ]+,[\r\n\t ]+/s' => '},',
//remove new-line after JS's function or condition start; join with next line
'/\)[\r\n\t ]?{[\r\n\t ]+/s' => '){',
'/,[\r\n\t ]?{[\r\n\t ]+/s' => ',{',
//remove new-line after JS's line end (only most obvious and safe cases)
'/\),[\r\n\t ]+/s' => '),',
//remove quotes from HTML attributes that does not contain spaces; keep quotes around URLs!
'~([\r\n\t ])?([a-zA-Z0-9]+)="([a-zA-Z0-9_/\\-]+)"([\r\n\t ])?~s' => '$1$2=$3$4', //$1 and $4 insert first white-space character found before/after attribute
);
$body = preg_replace(array_keys($replace), array_values($replace), $body);
//remove optional ending tags (see http://www.w3.org/TR/html5/syntax.html#syntax-tag-omission )
$remove = array(
'</option>', '</li>', '</dt>', '</dd>', '</tr>', '</th>', '</td>'
);
$body = str_ireplace($remove, '', $body);
$response->setBody($body);
}
}
Tuttavia, quando si utilizza la compressione gZip, il codice viene compresso molto più di qualsiasi minificazione, pertanto la combinazione di minificazione e gZip è inutile, poiché il tempo risparmiato dal download viene perso dalla minificazione e consente di risparmiare anche il minimo.
Ecco i miei risultati (download tramite rete 3G):
Original HTML: 150kB 180ms download
gZipped HTML: 24kB 40ms
minified HTML: 120kB 150ms download + 150ms minification
min+gzip HTML: 22kB 30ms download + 150ms minification
ob_start(function($b){return preg_replace(['/\>[^\S ]+/s','/[^\S ]+\</s','/(\s)+/s'],['>','<','\\1'],$b);});