在Phalcon中为View添加缓存

我们可以为Phalcon的View添加事件监听，View一共有5个事件：

Event Name	Triggered	Can stop operation ?
beforeRender	Triggered before starting the render process	Yes
beforeRenderView	Triggered before rendering an existing view	Yes
afterRenderView	Triggered after rendering an existing view	No
afterRender	Triggered after completing the render process	No
notFoundView	Triggered when a view was not found	No

在di注入是view时添加事件：

<?php

use Phalcon\Events\Event;
use Phalcon\Events\Manager as EventsManager;
use Phalcon\Mvc\View;

$di->set(
    'view',
    function () {
        // Create an events manager
        $eventsManager = new EventsManager();

        // Attach a listener for type 'view'
        $eventsManager->attach(
            'view',
            function (Event $event, $view) {
                echo $event->getType(), ' - ', $view->getActiveRenderPath(), PHP_EOL;
            }
        );

        $view = new View();

        $view->setViewsDir('../app/views/');

        // Bind the eventsManager to the view component
        $view->setEventsManager($eventsManager);

        return $view;
    },
    true
);

上面是监听了View的所有事件,如果要监听某个具体的,如监听beforeRender：

$eventsManager->attach('view:beforeRender', function(){

})

现在，就可以利用afterRender事件来缓存页面，提升性能。

首先，需要向di注入一个viewCache服务：

<?php

use Phalcon\Cache\Frontend\Output as OutputFrontend;
use Phalcon\Cache\Backend\Memcache as MemcacheBackend;

// Set the views cache service
$di->set(
    'viewCache',
    function () {
        // Cache data for one day by default
        $frontCache = new OutputFrontend(
            [
                'lifetime' => 86400,
            ]
        );

        // Memcached connection settings
        $cache = new MemcacheBackend(
            $frontCache,
            [
                'host' => 'localhost',
                'port' => '11211',
            ]
        );

        return $cache;
    }
);

这里的cache也可以换成Redis等你在使用的。lifetime为默认缓存时间，当调用该服务时，可以另外给出lifetime的值。键为key。Phalcon会默认使用MD5加密当前的Controller/view。

定义afterRender事件触发时要做的事情:

class ViewPlugin extends \Phalcon\Mvc\User\Plugin {

    public function afterRender(\Phalcon\Events\Event $event, $view){
        $request    = \Phalcon\Di::getDefault()->get('request');
        $key        = md5($request->getURI());
        if (!$view->getCache()->exists($key)) {
            $view->getCache()->save($key, $view->getContent(), DEFAULT_VIEW_EXPIRE_TIME);
        }
    }
}

这样当访问一个新页面后就会缓存下来。接下来就是第二步，再次访问该页面时，直接向浏览器输出缓存内容，可以定义在父类里：

$this->view_cache_key = md5($this->request->getURI());
if ($this->view->getCache()->exists($this->view_cache_key)) {
    echo $this->view->getCache()->get($this->view_cache_key);
    exit;
}

这就是利用View的事件缓存页面，当然也可以用于其他场景，如生成静态HTML页面

参考文档:

Phalcon view