nocache_headers()

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概述

nocache_headers() 函数用于设置 HTTP 头部，以阻止不同浏览器的缓存行为。它通过发送多个头部来确保所有浏览器都能正确识别不应缓存内容。

关键要点

函数发送多种 HTTP 头部以防止浏览器缓存，兼容不同浏览器。
内部调用 wp_get_nocache_headers() 获取头部信息，并移除 Last-Modified 头部。
如果头部已发送，函数会提前返回，避免错误。
常用于需要禁用缓存的场景，如错误处理、登录验证或自定义管理页面。

代码示例

add_filter( 'nocache_headers', function() {
    return array(
        'Cache-Control' => 'no-store, no-cache, must-revalidate, max-age=0, some-custom-thing',
        'Pragma'        => 'no-cache',
        'Expires'       => gmdate( 'D, d M Y H:i:s \G\M\T', time() )
    );
} );

注意事项

函数在 WordPress 2.0.0 版本引入，使用时需确保头部未提前发送。
可通过 nocache_headers 过滤器自定义头部，如示例中所示。

📄 原文内容

Sets the HTTP headers to prevent caching for the different browsers.

Description

Different browsers support different nocache headers, so several headers must be sent so that all of them get the point that no caching should occur.

More Information

Usage:

nocache_headers();

Source

function nocache_headers() {
	if ( headers_sent() ) {
		return;
	}

	$headers = wp_get_nocache_headers();

	unset( $headers['Last-Modified'] );

	header_remove( 'Last-Modified' );

	foreach ( $headers as $name => $field_value ) {
		header( "{$name}: {$field_value}" );
	}
}

View all references View on Trac View on GitHub

Uses	Description
wp_get_nocache_headers()`wp-includes/functions.php`	Gets the HTTP header information to prevent caching.

Used by	Description
_jsonp_wp_die_handler()`wp-includes/functions.php`	Kills WordPress execution and displays JSONP response with an error message.
_xml_wp_die_handler()`wp-includes/functions.php`	Kills WordPress execution and displays XML response with an error message.
_json_wp_die_handler()`wp-includes/functions.php`	Kills WordPress execution and displays JSON response with an error message.
wp_start_scraping_edited_file_errors()`wp-includes/load.php`	Starts scraping edited file errors.
WP_Customize_Manager::customize_preview_init()`wp-includes/class-wp-customize-manager.php`	Prints JavaScript settings.
auth_redirect()`wp-includes/pluggable.php`	Checks if a user is logged in, if not it redirects them to the login page.
WP::handle_404()`wp-includes/class-wp.php`	Set the Headers for 404, if nothing is found for requested URL.
wp_not_installed()`wp-includes/load.php`	Redirects to the installer if WordPress is not installed.
_default_wp_die_handler()`wp-includes/functions.php`	Kills WordPress execution and displays HTML page with an error message.
_ajax_wp_die_handler()`wp-includes/functions.php`	Kills WordPress execution and displays Ajax response with an error message.
_xmlrpc_wp_die_handler()`wp-includes/functions.php`	Kills WordPress execution and displays XML response with an error message.

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Changelog

Version	Description
2.0.0	Introduced.

User Contributed Notes

Skip to note 2 content

iSaumya

6 years ago

Use nocache_headers to add custom headers to wp-admin pages. Example code:

add_filter( 'nocache_headers', function() {
    return array(
        'Cache-Control' => 'no-store, no-cache, must-revalidate, max-age=0, some-custom-thing',
        'Pragma'        => 'no-cache',
        'Expires'       => gmdate( 'D, d M Y H:i:s GMT', time() )
    );
} );

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