在PHP中回答HTTP_IF_MODIFIED_SINCE和HTTP_IF_NONE_MATCH [英] Answering HTTP_IF_MODIFIED_SINCE and HTTP_IF_NONE_MATCH in PHP

问题描述

我使用PHP 5.1.0+制作了可缓存的动态内容。我已经将正确的标题（包括Last-Modified和ETag）发送给客户端。

我现在希望我的脚本能够回答 $ _ SERVER ['HTTP_IF_MODIFIED_SINCE'] 和 $ _ SERVER ['HTTP_IF_NONE_MATCH'] 存在时。当条件匹配时，我想向客户回答 HTTP 304Not Modified。

什么是正确的条件？当我发出一个304而不是整个内容？

有问题的接受答案
如何知道何时发送一个304 Not Modified响应似乎正确地发布了这个，但是我

谢谢！

解决方案

我一直使用：

 函数caching_headers（$ file，$ timestamp）{
 $ gmt_mtime = gmdate（'r'，$ timestamp）; 
 header（'ETag：''.md5（$ timestamp。$ file）。''）; 
 header（'Last-Modified：'。$ gmt_mtime）; 
 header（'Cache-Control：public'）; 
 
 if（isset（$ _ SERVER ['HTTP_IF_MODIFIED_SINCE']）|| isset（$ _ SERVER ['HTTP_IF_NONE_MATCH']））{
 if（$ _SERVER ['HTTP_IF_MODIFIED_SINCE'] == $ gmt_mtime || str_replace（'''，''，stripslashes（$ _ SERVER ['HTTP_IF_NONE_MATCH']））== md5（$ timestamp。$ file））{
 header（'HTTP / 1.1 304 Not Modified'） ; 
 exit（）; 
} 
} 
} 
  

不记得我是写了它还是从其他地方得到它......

我通常以这种方式在文件顶部使用它：
$ b $ pre code $ caching_headers（$ _SERVER ['SCRIPT_FILENAME']，filemtime（$ _ SERVER ['SCRIPT_FILENAME']））;

I have cacheable dynamic content made in PHP 5.1.0+. I already send the correct headers (including Last-Modified and ETag) to clients.

I now want my script to be able to answer $_SERVER['HTTP_IF_MODIFIED_SINCE'] and $_SERVER['HTTP_IF_NONE_MATCH'] when present. When the conditions matches, I want to answer a HTTP 304 "Not Modified" to clients.

What are the correct conditions? When exactly I issue a 304 instead of the whole content?

The accepted answer in question How to know when to send a 304 Not Modified response seems to issue this correctly but I have hard times to port that code to PHP 5.

Thank you!

解决方案

I've always used:

function caching_headers ($file, $timestamp) {
    $gmt_mtime = gmdate('r', $timestamp);
    header('ETag: "'.md5($timestamp.$file).'"');
    header('Last-Modified: '.$gmt_mtime);
    header('Cache-Control: public');

    if(isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) || isset($_SERVER['HTTP_IF_NONE_MATCH'])) {
        if ($_SERVER['HTTP_IF_MODIFIED_SINCE'] == $gmt_mtime || str_replace('"', '', stripslashes($_SERVER['HTTP_IF_NONE_MATCH'])) == md5($timestamp.$file)) {
            header('HTTP/1.1 304 Not Modified');
            exit();
        }
    }
}

Don't remember whether I wrote it or got it from somewhere else...

I'm normally using it at the top of a file in this way:

caching_headers ($_SERVER['SCRIPT_FILENAME'], filemtime($_SERVER['SCRIPT_FILENAME']));

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