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Summary of PHP page caching implementation methods_PHP tutorial
- WBOYOriginal
- 2016-07-20 11:11:09843browse
In PHP page caching, the ob series of functions are mainly used, such as ob_start(), ob_end_flush(), and ob_get_contents(). However, more advanced caching does not use these functions. The last implementation of this article is mentioned. You can For reference.
ob_start(): The sign that the page cache starts. The content under this function is saved in the page cache until ob_end_flush() or ob_end_clean();
ob_get_contents(): Used to obtain the content in the page cache. Get In the future, we can process these contents however we want, filter fields, match content, etc.~~~:)
ob_end_flush(): Indicates the end of page caching. And I have verified that the cached content will be output to the current page, that is, the cached content can be displayed.
Using these three php functions, you can achieve powerful functions. If the database query volume is large, cache can be used to solve this problem.
The following is the encoding part.
1. Initialization function, usually setting the page cache path, cache file naming format, etc., which can be customized according to personal preferences. The identification ID used here is the encrypted $_SERVER[REQUEST_URI] parameter. There is an if judgment at the end of this function: if the cache period has not passed, load the cache file, otherwise load the source file.
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{ $url = $_SERVER['REQUEST_URI'];//Sub-url, this parameter is generally unique
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| function page_cache($ttl = 0) { $ttl = $ttl ? $ttl : PAGE_TTL;//Cache time, default 3600s $ contents = ob_get_contents();//Get content from cache $contents = "n".$contents; //Add a custom header: expiration time = generation time + cache time file_put_contents(PAGE_FILE, $contents);//Write to the cache file ob_end_flush();//Release the cache } | |
3. When using functions, please note that these two functions are executed in sequence, and don’t forget ob_start()
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page_init( ); // Page cache initialization ob_start();// Is the last line ?> | |||||
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$_time =10; function cache_start($_time, $dir) function cache_end($dir) cache_start($_time, $dir); | |
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| $_time =10; $dir="D:php";<🎜><🎜>function cache_start($_time, $ dir) { $cachefile = $dir.'/'.sha1($_SERVER['REQUEST_URI']).'.html'; $cachetime = $_time; ob_start(); if(file_exists($cachefile) && (time()-filemtime($cachefile) < $cachetime)) { include($cachefile); ob_end_flush(); exit; } }<🎜><🎜>function cache_end($dir) { $cachefile = $dir.' /'.sha1($_SERVER['REQUEST_URI']).'.html'; $fp = fopen($cachefile, 'w'); fwrite($fp, ob_get_contents()); fclose($fp); ob_end_flush(); }<🎜><🎜>cache_start($_time, $dir); //The following is the output content, Place between cache_start and cache_end methods for ($i=0;$i<5;$i++) { echo $i; sleep(1) ; } cache_end($dir); ?> | |
Example
Using generated files for caching
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/**
* @author He Minghui
* @copyright 2009-3-13
* @param string $cache_folder cache folder
* @param int $cache_create_time file cache time
* @example $cache=new Esj_Cache('./_cache',100)
* @example $cache->read_cache() reads the cache and outputs
* @example $cache->creatre_cache () Create a cache file (put it at the end of the file)
* @example $cache->list_file() Returns a list of all cache files
* @example $cache->del_file() Delete all caches Document
*/class Esj_Cache{
private $cache_folder=null;//cacher folder
private $wroot_dir=null;//site directory
private $cacher_create_time=null;//creation of cacher file Timepublic function __construct($cache_foldername,$cacher_time=100)
{
ob_start();
$this->wroot_dir=$_SERVER['DOCUMENT_ROOT'] ;
$this->cache_folder=$cache_foldername;
$this->cacher_create_time=$cacher_time;
}public function read_cache()
{
try {
if(self::create_folder($this->cache_folder))
{
self::get_cache();//Output cache file information
}else
{
echo "Cache folder creation failed!";
return false;
}}catch(Exception $e){
echo $e;
return false;
}
}//Test whether the cache folder exists
private function exist_folder($foler)
{
if(file_exists($this->wroot_dir."/".$foler)){
return true;
}else {
return false;
}
}//Create a new folder
private function create_folder($foler)
{
if(!self::exist_folder( $foler))
{
try{
mkdir($this->wroot_dir."/".$foler,0777);
chmod($this->wroot_dir ."/".$foler,0777);
return true;
}catch (Exception $e)
{
self::get_cache();//Output cachereturn false;
}
return false;
}
else
{
return true;
}
} //Read cache file
private function get_cache()
{
$file_name=self::get_filename();
if (file_exists($file_name )&&((filemtime($file_name)+$this->cacher_create_time) > time()))
{
$content=file_get_contents($file_name);
if($content )
{
echo $content;
ob_end_flush();
exit;
}else
{
echo "File reading failed" ;
exit;}}
}//Return the name of the file
private function get_filename()
{
$filename=$file_name=$this->wroot_dir.'/'.$this->cache_folder.'/'.md5($_SERVER['QUERY_STRING']).".html";
return $filename;
}//Create cache file
public function create_cache()
{
$filename=self::get_filename( );
if($filename!="")
{
try{
file_put_contents($filename,ob_get_contents());
return true;
}catch (Exception $e)
{
echo "Write cache failed:".$e;
exit();
}
return true;
}
}// Get all files in the cache
public function list_file()
{
$path=$this->cache_folder;
if ($handle = opendir($path)) {
while (false !== ($file = readdir($handle))) {
if($file!=". " && $file!="..") {
$path1=$path."/".$file;
if(file_exists($path1))
{
$result[]=$file;
}
}
}
closedir($handle);
}
return $result;
}//Delete all files in the cache
public function del_file()
{
$path=$this->cache_folder;
if ($ handle = opendir($path)) {
while (false !== ($file = readdir($handle))) {
if($file!="." && $file!=" ..") {
$path1=$path."/".$file;
if(file_exists($path1))
{
unlink($path1);}
}
}
closedir($handle);
}
return true;
}}?>