Zend how to use cache component

Let's say you have this sc开发者_运维知识库enario:a simple blog home-page that loads both static content as well as dynamic content. The static content is composed of images that rarely changes.I also have database-driven,dynamic content.The dynamic content consists in all of your blog posts (text and image) and related users comments.The dynamic content changes periodically from every hour to every day.

How would you go with caching?And in particular supposing a user is leaving a comment or the admin is adding/editing a post to you would want to manually trigger the cache clearing to have the update version of this blog home-page?

thanks for your patience.

Luca

thanks again

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First, a link: http://framework.zend.com/manual/1.11/en/zend.cache.html

Basically, what you need to do is set up a cache mechanism and then manually call it when you want to retrieve something from the cache.

In the bootstrap, I might have this code:

public function _initCache () {
    $cache = Zend_Cache::factory(
        'Core',
        'File',
        array(
            'lifetime' => 3600 * 24, //cache is cleaned once a day
            'automatic_serialization' => true
        ),
        array('cache_dir' => APPLICATION_PATH.'/cache')
    );
    Zend_Db_Table_Abstract::setDefaultMetadataCache($cache); //cache database table schemata metadata for faster SQL queries
    Zend_Registry::set('Cache', $cache);
}

Then, you may use the load() and save() functions to manipulate the cache. An example from my controller:

$cache = Zend_Registry::get('Cache');
if (!$this->menu = $cache->load('main_menu')) {
    $model = new Model_Menu();
    $this->menu = $model->get();
    $cache->save($this->menu,'main_menu');
}

Here, I check whether the key "main_menu" is cached. If a cache miss is scored, the main menu is generated and cached.

If I edit the main menu, I'll want to regenerate the cache as well. I simply call this:

Zend_Registry::get('Cache')->remove('main_menu');

It's pretty simple, just read the documentation. It's well written.

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Zend cache provide a very simple way to store data in cache and to increase the speed. Zend uses frontend and back end to caching. Front end is useful to access or operate the cache. Back end is useful to store data in File , memcache, Sqlite etc.

First of all initialize the fronted and backed in bootstrap file by creating on function in bootstrap file.

protected function _initCache(){

    $frontend= array(
        'lifetime' => 7200,
        'automatic_serialization' => true
    );

    $backend= array(
        'cache_dir' => '../application/tmp/',
    );

    $cache = Zend_Cache::factory('core',
            'File',
            $frontend,
            $backend
    );
    Zend_Registry::set('cache',$cache);
}

Then use the zend cache factory to define the cache object. The parameter core define the zend cache core means of generic type File parameter is to define the cache storage means where to store the records of cache then second and forth is for frontend and backend.

Now register that cache array using zend registry so that you can use that are in any controller , model etc.

Define Below code in any controller or any model where you want to use caching of data.

    $result1 =””;
    $cache = Zend_Registry::get('cache');

if(!$result1 = $cache->load('mydata')) {
        echo 'caching the data…..';
    $data=array(1,2,3);
    $cache->save($data, 'mydata');
} else {
    echo 'retrieving cache data…….';
    Zend_Debug::dump($result1);
}

First of all in above code we get the cache array. Now if result one is not set then caching done means the file is generated at the path that you define in back-end array

For the Next time page load that data is retrieve from the file where the caching data store.

You can check the file as per defined path.

In that file data is in json format.

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So the basic usage of cache is shown by @mingos. He talks about generic cache, which is good. However, ZF has few different cache mechanisms that you can use for different things. You don't need to limit yourself for one type of cache. You can use a mixture of them. For example, for caching your static content Zend_Cache_Frontend_Page would be worth considering as it would generate a full html file of your static pages. If you have lots of config files, e.g. long routes.ini or whatever, you can cache them using Zend_Cache_Frontend_File. With this you would save time parsing the ini files for every request. Significant parts of your views could be cached using Zend_Cache_Frontend_Output, etc.

What to cache and when to update a cache is a tricky question. It all depends on how fast and how often your content is changing. For example, if you have like 100 new comments per second, there is no point in cleaning your comment cache 100 times per second (i.e. for each new comment). It would be better maybe to have comments for each post cached separately from the comments of other posts. Then you would clean/refresh a cache associated with only this post.

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A simple cache is one that times out after the defined period of time. This keeps the caching layer simple and easy to implement. The Zend Manual has more information on caching basics.

However real-time information and cached information are two worlds. If you need real-time, don't cache.

If you make the caching layer too complex, you can destroy your whole application.