mirror of
https://github.com/seigler/simple-php-buffering
synced 2025-07-26 01:06:14 +00:00
71 lines
2.1 KiB
PHP
71 lines
2.1 KiB
PHP
<?php
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// Based on code from The Art of Web: www.the-art-of-web.com
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// Which was based on PHP code by Dennis Pallett: www.phpit.net
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// location and prefix for cache files
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defined('CACHE_PATH') or define('CACHE_PATH', sys_get_temp_dir().'/cache_');
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// how long to keep the cache files (seconds)
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defined('CACHE_TIME') or define('CACHE_TIME', 5 * 60);
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// return location and name for cache file
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function cache_file()
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{
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return CACHE_PATH . md5('buffer'.$_SERVER['REQUEST_URI']);
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}
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// display cached file if present and not expired
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function cache_display()
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{
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$file = cache_file();
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// check that cache file exists and is not too old
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if(!file_exists($file)) return;
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$last_modified_time = filemtime($file);
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if($last_modified_time < time() - CACHE_TIME) return;
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$etag = md5_file($file);
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// always send headers
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header("Last-Modified: ".gmdate("D, d M Y H:i:s", $last_modified_time)." GMT");
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header("Etag: $etag");
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header("Expires: ".gmdate("D, d M Y H:i:s", $last_modified_time + CACHE_TIME)." GMT");
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// tell any caches that I really mean it with these other headers
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header("Cache-Control: max-age=".CACHE_TIME.", must-revalidate");
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// HTTP 304 and exit if not modified
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if (@strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) == $last_modified_time ||
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@trim($_SERVER['HTTP_IF_NONE_MATCH']) == $etag) {
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header("HTTP/1.1 304 Not Modified");
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exit;
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}
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// if so, display cache file and stop processing
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readfile($file);
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exit;
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}
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// write to cache file
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function cache_page($content)
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{
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if(false !== ($f = @fopen(cache_file(), 'w'))) {
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fwrite($f, $content);
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fclose($f);
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}
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$last_modified_time = time();
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$etag = md5_file('buffer'.$file);
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// always send headers
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header("Last-Modified: ".gmdate("D, d M Y H:i:s", $last_modified_time)." GMT");
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header("Etag: $etag");
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header("Expires: ".gmdate("D, d M Y H:i:s", $last_modified_time + CACHE_TIME)." GMT");
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return $content;
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}
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// execution stops here if valid cache file found
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cache_display();
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// enable output buffering and create cache file
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ob_start('cache_page');
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?>
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