Phpheader () function setting Page Cache _ PHP Tutorial-php Tutorial

The phpheader () function sets the page Cache. The header () function is widely used in php. I will introduce some methods to implement page cache using it. However, before using the header, you must note that no output can be made before it, contains spaces. The header () function is widely used in php. I will introduce some methods to implement page cache using it. However, before using the header, you must note that no output can be made before it, contains spaces.

In the manual, we write how to set the cache so that the code is not cached:

The code is as follows:
Header ("Cache-Control: no-store, no-cache, must-revalidate, post-check = 0, pre-check = 0"); // HTTP/1.1 Header ("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Date in the past Header ("Pragma: no-cache"); // Date in the past

In addition, you must note that no output is available before the header. Otherwise, the header settings are invalid but have not been written. how to set Cache for the page, although we know there are some ways, such as E-TAG. Of course, there are also simple settings:

For example, if we perform md5 on the content before the output and treat it as an e-tag, it will not be affected if it does not change. There are other methods:

The code is as follows:
$ Seconds_to_cache = 3600; $ Ts = gmdate ("D, d m y h: I: s", time () + $ seconds_to_cache). "GMT "; Header ("Expires: $ ts"); header ("Pragma: cache "); Header ("Cache-Control: max-age = $ seconds_to_cache ");

Cache for 1 hour, mainly because gmdate is used to set the expiration time, instead of date. Note that the rest is similar. Maxage must be able to match expire.

For dynamic content generated by PHP, you only need to output the mandatory cache header before the content is output. for example, the following code requires the browser to cache the file for one month:

The code is as follows:
Header ("Cache-Control: public "); Header ("Pragma: cache "); $ Offset = 30*60*60*24; // cache 1 month $ ExpStr = "Expires:". gmdate ("D, d m y h: I: s", time () + $ offset). "GMT "; Header ($ ExpStr ); ?>

For static files, the server generally supports a cache status of 3rd. To achieve the fourth level of cache effect, you can use PHP to outsource a layer and then use PHP to process the layer as before GZIP compression. Either the server-side support is required. the mod_expires module of APACHE supports adding the expires header to the file. Add the following code to your blog directory. htaccess file. if the mod_expires module is installed on your server, the file takes effect automatically. images are forcibly cached for one month, and html files are cached for 10 minutes. If this module is not installed, no error will occur.

The code is as follows:
ExpiresActive On ExpiresByType image/gif A2592000 ExpiresByType image/jpeg A2592000 ExpiresByType image/png A2592000 ExpiresByType application/x-shockwave-flash A2592000 ExpiresByType text/css A2592000 ExpiresByType application/x-javascript A2592000 ExpiresByType text/html A600

Here are more detailed documents and tutorials for mod_expires. However, mod_expires is not installed on most servers.

The http://www.bkjia.com/PHPjc/631539.htmlwww.bkjia.comtruehttp://www.bkjia.com/PHPjc/631539.htmlTechArticleheader () function is widely used in php. below I will introduce some methods to use it to implement page cache, but before using the header, you must note that there is no output before it, including spaces ....