framework/filters/HttpCache.php
public function beforeAction($action)
    {
        if (!$this->enabled) {
            return true;
        }

        $verb = Yii::$app->getRequest()->getMethod();
        if ($verb !== 'GET' && $verb !== 'HEAD' || $this->lastModified === null && $this->etagSeed === null) {
            return true;
        }

        $lastModified = $etag = null;
        if ($this->lastModified !== null) {
            $lastModified = call_user_func($this->lastModified, $action, $this->params);
        }
        if ($this->etagSeed !== null) {
            $seed = call_user_func($this->etagSeed, $action, $this->params);
            if ($seed !== null) {
                $etag = $this->generateEtag($seed);
            }
        }

        $this->sendCacheControlHeader();

        $response = Yii::$app->getResponse();
        if ($etag !== null) {
            $response->getHeaders()->set('Etag', $etag);
        }

        $cacheValid = $this->validateCache($lastModified, $etag);
        // https://tools.ietf.org/html/rfc7232#section-4.1
        if ($lastModified !== null && (!$cacheValid || ($cacheValid && $etag === null))) {
            $response->getHeaders()->set('Last-Modified', gmdate('D, d M Y H:i:s', $lastModified) . ' GMT');
        }
        if ($cacheValid) {
            $response->setStatusCode(304);
            return false;
        }

        return true;
    }
public function beforeAction($action)
    {
        if (!$this->enabled) {
            return true;
        }

        $verb = Yii::$app->getRequest()->getMethod();
        if ($verb !== 'GET' && $verb !== 'HEAD' || $this->lastModified === null && $this->etagSeed === null) {
            return true;
        }

        $lastModified = $etag = null;
        if ($this->lastModified !== null) {
            $lastModified = call_user_func($this->lastModified, $action, $this->params);
        }
        if ($this->etagSeed !== null) {
            $seed = call_user_func($this->etagSeed, $action, $this->params);
            if ($seed !== null) {
                $etag = $this->generateEtag($seed);
            }
        }

        $this->sendCacheControlHeader();

        $response = Yii::$app->getResponse();
        if ($etag !== null) {
            $response->getHeaders()->set('Etag', $etag);
        }

        $cacheValid = $this->validateCache($lastModified, $etag);
        // https://tools.ietf.org/html/rfc7232#section-4.1
        if ($lastModified !== null && (!$cacheValid || ($cacheValid && $etag === null))) {
            $response->getHeaders()->set('Last-Modified', gmdate('D, d M Y H:i:s', $lastModified) . ' GMT');
        }
        if ($cacheValid) {
            $response->setStatusCode(304);
            return false;
        }

        return true;
    }
public function beforeAction ( $ action ) { if ( ! $ this -> enabled ) { return true ; } $ verb = Yii :: $ app -> getRequest ( ) -> getMethod ( ) ; if ( $ verb !== 'GET' && $ verb !== 'HEAD' || $ this -> lastModified === null && $ this -> etagSeed === null ) { return true ; } $ lastModified = $ etag = null ; if ( $ this -> lastModified !== null ) { $ lastModified = call_user_func ( $ this -> lastModified , $ action , $ this -> params ) ; } if ( $ this -> etagSeed !== null ) { $ seed = call_user_func ( $ this -> etagSeed , $ action , $ this -> params ) ; if ( $ seed !== null ) { $ etag = $ this -> generateEtag ( $ seed ) ; } } $ this -> sendCacheControlHeader ( ) ; $ response = Yii :: $ app -> getResponse ( ) ; if ( $ etag !== null ) { $ response -> getHeaders ( ) -> set ( 'Etag' , $ etag ) ; } $ cacheValid = $ this -> validateCache ( $ lastModified , $ etag ) ; // https://tools.ietf.org/html/rfc7232#section-4.1 if ( $ lastModified !== null && ( ! $ cacheValid || ( $ cacheValid && $ etag === null ) ) ) { $ response -> getHeaders ( ) -> set ( 'Last-Modified' , gmdate ( 'D, d M Y H:i:s' , $ lastModified ) . ' GMT' ) ; } if ( $ cacheValid ) { $ response -> setStatusCode ( 304 ) ; return false ; } return true ; }
This method is invoked right before an action is to be executed (after all possible filters.)
You may override this method to do last-minute preparation for the action.
@param Action $action the action to be executed.
@return bool whether the action should continue to be executed.
This method is invoked right before an action is to be executed ( after all possible filters . ) You may override this method to do last - minute preparation for the action .