How to use Memcache with PHP

How to use Memcache with PHP

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Memcache with PHP

Memcache with PHP

Today I have new article for PHP. Last time I did post about Memcache with PHP. Today we will talking about caching in PHP again. I will show you how you can use Memcache in PHP. We will prepare useful class for working with Memcache for us and several examples. Memcache itself providing procedural and object oriented interface to memcached, highly effective caching daemon, which was especially designed to decrease database load in dynamic web applications.

I don`t have online demo for today, just because haven`t installed Memcache at our hosting. But I will include samples of using our new library in this article too (as I did for our previous APC-related post). Also, pay attention that Memcache extension not bundled with PHP by default. This extension available in PECL. Additional information you can find here.

download in package

Now – download the source files and lets start coding !


Step 1. PHP

I made this useful class for you. We will use this class to working with memory using Memcache system.

classes/memcache.caching.php

<?

class CacheMemcache {
   
    var $iTtl = 600; // Time To Live
    var $bEnabled = false; // Memcache enabled?
    var $oCache = null;
 
    // constructor
    function CacheMemcache() {
        if (class_exists('Memcache')) {
            $this->oCache = new Memcache();
            $this->bEnabled = true;
            if (! $this->oCache->connect('localhost', 11211))  { // Instead 'localhost' here can be IP
                $this->oCache = null;
                $this->bEnabled = false;
            }
        }
    }

    // get data from cache server
    function getData($sKey) {
        $vData = $this->oCache->get($sKey);
        return false === $vData ? null : $vData;
    }

    // save data to cache server
    function setData($sKey, $vData) {
        //Use MEMCACHE_COMPRESSED to store the item compressed (uses zlib). 
        return $this->oCache->set($sKey, $vData, 0, $this->iTtl);
    }

    // delete data from cache server
    function delData($sKey) {
        return $this->oCache->delete($sKey);
    }
}

?>

I prepared here several necessary functions which we will use: getData, setData and delData. Now, lets check first example file:

index.php

<?php

$aData = array(
    'name' => 'table',
    'color' => 'brown',
    'size' => array(
        'x' => 200,
        'y' => 120,
        'z' => 150,
    ),
    'strength' => 10,
);

require_once('classes/memcache.caching.php');
$oCache = new CacheMemcache();

echo 'Initial data: <pre>'; // lets see what we have
print_r($aData);
echo '</pre>';


if ($oCache->bEnabled) { // if Memcache enabled

    $oCache->setData('my_object', $aData); // saving data to cache server
    $oCache->setData('our_class_object', $oCache); // saving object of our class into cache server too

    echo 'Now we saved all in cache server, click <a href="index2.php">here</a> to check what we have in cache server';

} else {
    echo 'Seems Memcache not installed, please install it to perform tests';
}

?>

In this file you can see that I saving 2 objects in memory: some predefined array and class object. Now, lets check second example file:

index2.php

<?php

require_once('classes/memcache.caching.php');
$oCache = new CacheMemcache();

if ($oCache->bEnabled) { // if Memcache enabled

    $aMemData = $oCache->getData('my_object'); // getting data from cache server
    $aMemData2 = $oCache->getData('our_class_object'); // getting data from cache server about our class

    echo 'Data from cache server: <pre>'; // lets see what we have from cache server
    print_r($aMemData);
    echo '</pre>';

    echo 'Data from cache server of object of CacheMemcache class: <pre>';
    print_r($aMemData2);
    echo '</pre>';

    echo 'As you can see - all data read successfully, now lets remove data from cache server and check results, click <a href="index3.php">here</a> to continue';

} else {
    echo 'Seems Memcache not installed, please install it to perform tests';
}

?>

Here we only reading data from memory. And, as we see – all data is successfully read from the memory. Now, lets check last example file:

index3.php

<?php

require_once('classes/memcache.caching.php');
$oCache = new CacheMemcache();

if ($oCache->bEnabled) { // if Memcache enabled

    $oCache->delData('my_object'); // removing data from cache server
    $oCache->delData('our_class_object'); // removing data from cache server

    $aMemData = $oCache->getData('my_object'); // lets try to get data again
    $aMemData2 = $oCache->getData('our_class_object');

    echo 'Data from cache server: <pre>'; // lets see what we have from cache server
    print_r($aMemData);
    echo '</pre>';

    echo 'Data from cache server of object of CacheMemcache class: <pre>';
    print_r($aMemData2);
    echo '</pre>';

    echo 'As you can see - all data successfully removed. Great !';

} else {
    echo 'Seems Memcache not installed, please install it to perform tests';
}

?>

download in archive

Conclusion

Today, I told you how we can use Memcache. I hope you got new thoughts on optimizing your website(s). Good luck in your work!


14 COMMENTS

  1. Good read, but I am curious/concerned about one thing. PHP5 changed the way you used classes, why do you, in 2011, still use the PHP4 way to develop your classes?

    • Hello pjack,
      Basically – you always can use our tutorial for database too.
      You can use ‘setData’ function to store anything in memory. Even results from database. Just imagine – you have extracted some information from DB (into array), then – you need to store this (array) to our cache (I will advise you to use some prefix to such Keys for database, as example db_). Then, next time, instead taking data directly from database – check, if memory contain necessary results using ‘getData’ function. And, if memory contain necessary results (not null) – use this data, otherwise – pick data from database and store results to cache after.

  2. I am using PHP to program and want to use memcache as well. How can I install memcache on a windows localhost ? any ideas ?

    have a good day

    • Hello yavuz,
      I can suspect that you use WAMP software to work on a windows localhost. If so – you have to click at WAMP icon, then: PHP -> PHP Extensions. And select ‘php_memcache’ in list to activate this extension.

  3. On MacOSX Lion with Xampp 1.7.3 I replace the constructor as followed :

    // constructor
    function CacheMemcache() {

    by

    // constructor
    function __construct() {

    And now it’s ok.

    • Hello Veer,
      Then, you have to put our library into your ‘CodeIgniter’ project, and, I hope that you know all inner sources of that project very well, only in this case you will be able to modify it’s sources to use methods of our class.

  4. HI Friends,

    thank you very much for share this knowledge, i would like to learn it and also work with it,
    i just download your zip file

    source
    ———–
    |- classes
    | |- memcache.caching.php
    |
    | – index.php
    |- index2.php
    |- index3.php

    i just execute my life by using http://localhost/source/example150/index.php

    i got following error:
    Fatal error: Call to a member function set() on a non-object in D:\xampp\htdocs\source\example150\memcache.caching.php on line 30

    i Executed index2.php file

    Fatal error: Call to a member function get() on a non-object in D:\xampp\htdocs\source\example150\memcache.caching.php on line 23

    please solve this error
    thanks in advance.

    • Hello kranthi,
      I think that it can be only in case if Memcache was not initialized. Make sure that it is installed at your localhost.

  5. Thank you. Usefull class.
    But fix error in the class please.
    14 if (! $this->oCache->connect(‘localhost’, 11211)) { // Instead ‘localhost’ here can be IP
    15 $this->oCache = null;
    16 $this->bEnabled = true; <– this must be false of cource
    17 }

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