How to use Memcache for data storage and reading in PHP development

How to use Memcache for data storage and reading in PHP development

Overview:
In Web development, data caching is one of the important ways to improve system performance. Memcache is a high-performance memory key-value storage system that can be used to cache commonly used data and reduce the number of database accesses. This article will introduce how to use Memcache for data storage and reading in PHP development, and provide code examples.

1. Installation and configuration of Memcache:
   First, we need to install the Memcache extension on the server. You can install it by running the following command:

   sudo apt-get install memcached
   sudo apt-get install php-memcached

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   After successful installation, you need to enable the Memcache extension in the php.ini file. You can find the location of the php.ini file by running the following command:

   php -i | grep php.ini

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   Find php.ini file, use a text editor to open the file and find the following line:

   ;extension=memcached.so

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   Change it to:

   extension=memcached.so

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   Save and exit the php.ini file, then restart the web server to enable The changes take effect.

2. Connecting Memcache:
   In PHP, we can use the Memcache class to connect and operate the Memcache server. First, we need to create a Memcache object:

   $memcache = new Memcache();

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   Then, use the connect() method to connect to the Memcache server, passing in the server’s IP address and port number:

   $memcache->connect('127.0.0.1', 11211);

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3. Storing and reading data:
   Next, we can use the set() method to store data into Memcache. The set() method accepts three parameters: key, value and expiration time (optional). The following is an example:

   $key = 'username';
   $value = 'John Doe';
   $expiration = 3600; // 数据过期时间为1小时
   $memcache->set($key, $value, 0, $expiration);

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   The above code stores the data with the key name 'username' and the value 'John Doe' into Memcache, and sets the expiration time to 1 hour.

To read data from Memcache, you can use the get() method. The get() method accepts one parameter: key. The following is an example:

$key = 'username';
$data = $memcache->get($key);
if ($data !== false) {
    // 数据存在
    echo "Username: " . $data;
} else {
    // 数据不存在或已过期
    echo "Username not found";
}

The above code will read data from Memcache based on the key name 'username' and determine whether the data exists. If it exists, the user name is output; if it does not exist or has expired, a prompt message is output.

4. Delete data:
   If you need to delete data from Memcache, you can use the delete() method. The delete() method accepts one parameter: key. The following is an example:

   $key = 'username';
   $memcache->delete($key);

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   The above code will delete the corresponding data from Memcache based on the key name 'username'.

5. Use case:
   The following is an example of using Memcache to cache data:

$memcache = new Memcache();
$memcache->connect('127.0.0.1', 11211);

function getUserData($userId) {
    global $memcache;
    $key = 'user_' . $userId;
    $userData = $memcache->get($key);
    if ($userData === false) {
        // 从数据库中获取用户数据
        $userData = getUserDataFromDatabase($userId);
        $expiration = 3600; // 数据过期时间为1小时
        $memcache->set($key, $userData, 0, $expiration);
    }
    return $userData;
}

$userId = 123;
$userData = getUserData($userId);
echo "User Name: " . $userData['name'];
echo "Email: " . $userData['email'];

The above code defines a getUserData() function for obtaining User data. First, the function will try to get the user data from Memcache; if the data does not exist, it will be obtained from the database and stored in Memcache for next time use. Finally, output the user's name and email address.

Conclusion:
Using Memcache for data storage and reading can greatly improve system performance and reduce access to the database. With the code examples provided in this article, you can easily use Memcache for data caching in PHP development. Hope this article helps you!

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