php实现根据url自动生成缩略图的方法

sudo a2enmod rewrite 

<IfModule mod_rewrite.c> 
RewriteEngine On 
 
# '-s' (is regular file, with size) 
# '-l' (is symbolic link) 
# '-d' (is directory) 
# 'ornext|OR' (or next condition) 
# 'nocase|NC' (no case) 
# 'last|L' (last rule) 
 
RewriteCond %{REQUEST_FILENAME} -s [OR] 
RewriteCond %{REQUEST_FILENAME} -l [OR] 
RewriteCond %{REQUEST_FILENAME} -d 
RewriteRule ^.*$ - [NC,L] 
RewriteRule ^.*$ createthumb.php?path=%{REQUEST_URI} [NC,L] 
 
</IfModule>

<?php
define('WWW_PATH', dirname(dirname(__FILE__))); // 站点www目录 
 
require(WWW_PATH.'/PicThumb.class.php'); // include PicThumb.class.php 
require(WWW_PATH.'/ThumbConfig.php');  // include ThumbConfig.php 
 
$logfile = WWW_PATH.'/createthumb.log'; // 日志文件 
$source_path = WWW_PATH.'/upload/';   // 原路径 
$dest_path = WWW_PATH.'/supload/';    // 目标路径 
 
$path = isset($_GET['path'])? $_GET['path'] : ''; // 访问的图片URL 
 
// 检查path 
if(!$path){ 
  exit(); 
} 
 
// 获取图片URI 
$relative_url = str_replace($dest_path, '', WWW_PATH.$path); 
 
// 获取type 
$type = substr($relative_url, 0, strpos($relative_url, '/')); 
 
// 获取config 
$config = isset($thumb_config[$type])? $thumb_config[$type] : ''; 
 
// 检查config 
if(!$config || !isset($config['fromdir'])){ 
  exit(); 
} 
 
// 原图文件 
$source = str_replace('/'.$type.'/', '/'.$config['fromdir'].'/', $source_path.$relative_url); 
 
// 目标文件  
$dest = $dest_path.$relative_url; 
 
// 创建缩略图 
$obj = new PicThumb($logfile); 
$obj->set_config($config); 
if($obj->create_thumb($source, $dest)){ 
  ob_clean(); 
  header('content-type:'.mime_content_type($dest)); 
  exit(file_get_contents($dest)); 
} 
 
?>

<?php 
 
$thumb_config = array( 
 
  'news' => array( 
    'fromdir' => 'news', // 来源目录 
    'type' => 'fit', 
    'width' => 100, 
    'height' => 100, 
    'bgcolor' => '#FF0000' 
  ), 
 
  'news_1' => array( 
    'fromdir' => 'news', 
    'type' => 'fit', 
    'width' => 200, 
    'height' => 200, 
    'bgcolor' => '#FFFF00' 
  ), 
 
  'article' => array( 
    'fromdir' => 'article', 
    'type' => 'crop', 
    'width' => 250, 
    'height' => 250, 
    'watermark' => WWW_PATH.'/supload/watermark.png' 
  ) 
 
); 
 
?>