<?php
namespace app\components;
use app\helpers\HtmlMinifyHelper;
use Yii;
use yii\base\Component;
use yii\base\Event;
use yii\web\Response;
use yii\web\View;
class HtmlMinify extends Component
{
 /**
  * Minify html. Process before response send
  * @var bool
  */
 public $html = false;
 /**
  * Minify css on page, added by registerCss. Process before render page in view component
  * @var bool
  */
 public $css = false;
 /**
  * Minify css on page. Process before render page in view component
  * @var bool
  */
 public $js = false;
 /**
  * Response formats list, where enable minify html
  * @var array
  */
 public $formats = [
  Response::FORMAT_HTML,
 ];
 public function init()
 {
  /** @var $this View */
  Yii::$app->view->on(View::EVENT_END_PAGE, [$this, 'onEventEndPage']);
  Yii::$app->response->on(Response::EVENT_BEFORE_SEND, [$this, 'onEventBeforeSend']);
 }
 public function onEventEndPage(Event $event)
 {
  $view = $event->sender;
  if ($this->css && !empty($view->css)) {
   foreach ($view->css as &$css) {
    $css = HtmlMinifyHelper::css($css);
   }
  }
  if ($this->js && !empty($view->js)) {
   foreach ($view->js as &$list) {
    foreach ($list as &$js) {
     $js = HtmlMinifyHelper::js($js);
    }
   }
  }
 }
 public function onEventBeforeSend(Event $event)
 {
  $response = $event->sender;
  if ($this->html & in_array($response->format, $this->formats)) {
   if (!empty($response->data)) {
    $response->data = HtmlMinifyHelper::html($response->data);
   }
   if (!empty($response->content)) {
    $response->content = HtmlMinifyHelper::html($response->content);
   }
  }
 }
}

<?php
namespace app\helpers;
class HtmlMinifyHelper
{
 public static function html($input)
 {
  if (trim($input) === "") {
   return $input;
  }
  // Remove extra white-space(s) between HTML attribute(s)
  $input = preg_replace_callback('#<([^\/\s<>!]+)(?:\s+([^<>]*?)\s*|\s*)(\/?)>#s', function ($matches) {
   return '<' . $matches[1] . preg_replace('#([^\s=]+)(\=([\'"]?)(.*?)\3)?(\s+|$)#s', ' $1$2', $matches[2]) . $matches[3] . '>';
  }, str_replace("\r", "", $input));
  // Minify inline CSS declaration(s)
  if (strpos($input, ' style=') !==false){   $input=preg_replace_callback('#<([^<]+?)\s+style=([\'"])(.*?)\2(?=[\/\s>])#s',function ($matches){    return '<' . $matches[1] . ' style=' . $matches[2] . self::css($matches[3]) . $matches[2];
   }, $input);
  }
  return preg_replace(
   [
    // t = text
    // o = tag open
    // c = tag close
    // Keep important white-space(s) after self-closing HTML tag(s)
    '#<(img|input)(>| .*?>)#s',
    // Remove a line break and two or more white-space(s) between tag(s)
    '#(<!--.*?-->)|(>)(?:\n*|\s{2,})(<)|^\s*|\s*$#s',
    '#(<!--.*?-->)|(?<!\>)\s+(<\/.*?>)|(<[^\/]*?>)\s+(?!\<)#s', // t+c || o+t
    '#(<!--.*?-->)|(<[^\/]*?>)\s+(<[^\/]*?>)|(<\/.*?>)\s+(<\/.*?>)#s', // o+o || c+c
    '#(<!--.*?-->)|(<\/.*?>)\s+(\s)(?!\<)|(?<!\>)\s+(\s)(<[^\/]*?\/?>)|(<[^\/]*?\/?>)\s+(\s)(?!\<)#s', // c+t || t+o || o+t -- separated by long white-space(s)
    '#(<!--.*?-->)|(<[^\/]*?>)\s+(<\/.*?>)#s', // empty tag
    '#<(img|input)(>| .*?>)<\/\1>#s', // reset previous fix
    '#( ) (?![<\s])#', // clean up ...
    '#(?<=\>)( )(?=\<)#', // --ibid
    // Remove HTML comment(s) except IE comment(s)
    '#\s*<!--(?!\[if\s).*?-->\s*|(?<!\>)\n+(?=\<[^!])#s',
   ],
   [
    '<$1$2</$1>',
    '$1$2$3',
    '$1$2$3',
    '$1$2$3$4$5',
    '$1$2$3$4$5$6$7',
    '$1$2$3',
    '<$1$2',
    '$1 ',
    '$1',
    "",
   ],
   $input);
 }
 public static function css($input)
 {
  if (trim($input) === "") {
   return $input;
  }
  return preg_replace(
   [
    // Remove comment(s)
    '#("(?:[^"\\\]++|\\\.)*+"|\'(?:[^\'\\\\]++|\\\.)*+\')|\/\*(?!\!)(?>.*?\*\/)|^\s*|\s*$#s',
    // Remove unused white-space(s)
    '#("(?:[^"\\\]++|\\\.)*+"|\'(?:[^\'\\\\]++|\\\.)*+\'|\/\*(?>.*?\*\/))|\s*+;\s*+(})\s*+|\s*+([*$~^|]?+=|[{};,>~+]|\s*+-(?![0-9\.])|!important\b)\s*+|([[(:])\s++|\s++([])])|\s++(:)\s*+(?!(?>[^{}"\']++|"(?:[^"\\\]++|\\\.)*+"|\'(?:[^\'\\\\]++|\\\.)*+\')*+{)|^\s++|\s++\z|(\s)\s+#si',
    // Replace `0(cm|em|ex|in|mm|pc|pt|px|vh|vw|%)` with `0`
    '#(?<=[\s:])(0)(cm|em|ex|in|mm|pc|pt|px|vh|vw|%)#si',
    // Replace `:0 0 0 0` with `:0`
    '#:(0\s+0|0\s+0\s+0\s+0)(?=[;\}]|\!important)#i',
    // Replace `background-position:0` with `background-position:0 0`
    '#(background-position):0(?=[;\}])#si',
    // Replace `0.6` with `.6`, but only when preceded by `:`, `,`, `-` or a white-space
    '#(?<=[\s:,\-])0+\.(\d+)#s',
    // Minify string value
    '#(\/\*(?>.*?\*\/))|(?<!content\:)([\'"])([a-z_][a-z0-9\-_]*?)\2(?=[\s\{\}\];,])#si',
    '#(\/\*(?>.*?\*\/))|(\burl\()([\'"])([^\s]+?)\3(\))#si',
    // Minify HEX color code
    '#(?<=[\s:,\-]\#)([a-f0-6]+)\1([a-f0-6]+)\2([a-f0-6]+)\3#i',
    // Replace `(border|outline):none` with `(border|outline):0`
    '#(?<=[\{;])(border|outline):none(?=[;\}\!])#',
    // Remove empty selector(s)
    '#(\/\*(?>.*?\*\/))|(^|[\{\}])(?:[^\s\{\}]+)\{\}#s',
   ],
   [
    '$1',
    '$1$2$3$4$5$6$7',
    '$1',
    ':0',
    '$1:0 0',
    '.$1',
    '$1$3',
    '$1$2$4$5',
    '$1$2$3',
    '$1:0',
    '$1$2',
   ],
   $input);
 }
 public static function js($input)
 {
  if (trim($input) === "") {
   return $input;
  }
  return preg_replace(
   [
    // Remove comment(s)
    '#\s*("(?:[^"\\\]++|\\\.)*+"|\'(?:[^\'\\\\]++|\\\.)*+\')\s*|\s*\/\*(?!\!|@cc_on)(?>[\s\S]*?\*\/)\s*|\s*(?<![\:\=])\/\/.*(?=[\n\r]|$)|^\s*|\s*$#',
    // Remove white-space(s) outside the string and regex
    '#("(?:[^"\\\]++|\\\.)*+"|\'(?:[^\'\\\\]++|\\\.)*+\'|\/\*(?>.*?\*\/)|\/(?!\/)[^\n\r]*?\/(?=[\s.,;]|[gimuy]|$))|\s*([!%&*\(\)\-=+\[\]\{\}|;:,.<>?\/])\s*#s',
    // Remove the last semicolon
    '#;+\}#',
    // Minify object attribute(s) except JSON attribute(s). From `{'foo':'bar'}` to `{foo:'bar'}`
    '#([\{,])([\'])(\d+|[a-z_][a-z0-9_]*)\2(?=\:)#i',
    // --ibid. From `foo['bar']` to `foo.bar`
    '#([a-z0-9_\)\]])\[([\'"])([a-z_][a-z0-9_]*)\2\]#i',
   ],
   [
    '$1',
    '$1$2',
    '}',
    '$1$3',
    '$1.$3',
   ],
   $input);
 }
}

'htmlMinify' => [
 'class' => 'app\components\HtmlMinify',
 'html' => !YII_ENV_DEV, // 这里只开启了html的
],