Let's talk about some common PHP cache writing methods

In website development, caching is an effective means to improve website performance. As one of the widely used programming languages, PHP also provides a variety of caching implementation methods. This article will introduce some common PHP cache writing methods to help developers optimize website performance.

1. File caching

File caching is a simple caching method that implements data caching by serializing data and writing it to a file. The code is implemented as follows:

function getCache($key, $lifetime) { $cacheFileName = md5($key) . '.cache'; // 产生缓存文件名 if(file_exists($cacheFileName) && (time() - filemtime($cacheFileName)) < $lifetime) { // 缓存未过期，直接读取缓存文件 return unserialize(file_get_contents($cacheFileName)); } else { // 缓存已过期或不存在，重新获取数据并缓存 $data = getData(); file_put_contents($cacheFileName, serialize($data)); return $data; } }

In the above code, we use file name generation rules to avoid cache file name conflicts, and at the same time determine whether the cache has expired each time the cache data is obtained, thereby ensuring the validity of the cache data. However, this method also has some flaws, such as the high cost of file system IO operations, which has a certain impact on server performance.

2. Memory cache

Memory cache is more efficient than file cache. It stores cached data in memory and does not require file system IO operations, thereby increasing the speed of data acquisition. There are two common memory caching solutions:

1. Memcache

Memcache is a memory-based distributed caching solution that can be used in multiple servers Perform read and write operations of cached data. Memcache's PHP extension provides a simple and easy-to-use interface, allowing developers to easily implement cache reading and writing operations of data. The code is implemented as follows:

$memcache = new Memcache; $memcache->connect('localhost', 11211); // 缓存读取操作 $data = $memcache->get($key); if($data === false) { // 缓存不存在，重新获取数据并缓存 $data = getData(); $memcache->set($key, $data); }

In the above code, we instantiate a Memcache object, and then establish a connection with the Memcache service of the local machine with port 11211. When performing cache operations, you only need to read and write to the cache through the get and set methods.

2. Redis

Redis is a memory-based high-performance non-relational database. It supports a variety of data structures and advanced caching strategies, and can support high concurrency and Fast and responsive network service. The PHP extension for Redis provides API support, allowing developers to easily use Redis as a caching solution.

$redis = new Redis(); $redis->connect('127.0.0.1', 6379); // 缓存读取操作 $data = $redis->get($key); if($data === false) { // 缓存不存在，重新获取数据并缓存 $data = getData(); $redis->set($key, $data); }

In the above code, we first connect to the Redis server, and then perform cache read and write operations through the get and set methods.

3. OPcache

OPcache is a bytecode cache extension that comes with PHP version 5.5.0. It can cache the code in the PHP file into memory, thereby improving the interpreter execution speed. Because the cache is bytecode, it can significantly reduce the time it takes for the interpreter to interpret PHP scripts. The method to open OPcache is very simple:

1. Modify the php.ini file

Find [OPcache] in the php.ini file and enable this extension:

; 打开OPcache扩展 zend_extension=opcache.so [opcache] ; 缓存内存大小 opcache.memory_consumption=128 ; 缓存路径 opcache.file_cache=/tmp ; 开启缓存 opcache.enable=1

2. Using OPcache in the code

$cacheFilePath = 'cache.txt'; // 判断缓存是否存在且未过期 if(!empty(opcache_get_status()) && @file_exists($cacheFilePath) && (time() - filemtime($cacheFilePath)) < 60) { $cache = include $cacheFilePath; } else { // 缓存不存在或已过期，重新获取数据并写入缓存文件 $data = getData(); // 将数据进行缓存 file_put_contents($cacheFilePath, "
        

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In the above code, we first determine whether OPcache is turned on, and then decide whether to read from the cache based on whether the cache file exists and whether the cache time has expired. Fetch the data or re-fetch the data. If the cache does not exist or has expired, we serialize the obtained data and write it into the cache file, and then read the data in the cache file through include.

4. Summary

The above are several common PHP cache writing methods. Each method has its own advantages and disadvantages. Developers need to choose an appropriate caching solution based on specific project conditions. Although file caching is easy to implement, it is inefficient. Although memory caching is highly efficient, the operation is relatively complex. OPcache is PHP's own bytecode caching extension. It does not need to be turned on manually. You only need to use specific functions in the code.

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