This article is the HTTP Header page cache control and header commonly used instructions for a detailed analysis of the introduction, the need for friends to reference the
The caching of the Web page is controlled by the "Cache-control" in the HTTP message header, and the common values are private, No-cache, Max-age, Must-revalidate, and so on, and the default is private. Its role is divided into the following situations according to different browsing methods:
(1) Open a new window
value is private, No-cache, Must-revalidate, then the server will be accessed when a new window is opened.
And if the Max-age value is specified, the server will not be accessed again in the time within this value, for example:
cache-control:max-age=5 (means to access the server again within 5 seconds of accessing this page)
(2) When the Address bar carriage return
value is private or must-revalidate, the server is accessed only for the first visit and is no longer accessible. The
value is No-cache and is accessed every time. The
value is Max-age, and no access is repeated until it expires.
(3) Press back button
to Private, must-revalidate, Max-age, no access,
value No-cache, repeat access every time
(4) Press the refresh button
to access this page does not leave a page backup on the Internet temporary article folder, regardless of the value, which will repeatedly access the
Cache-control value is "No-cache".
Additionally, caching is affected by specifying a "Expires" value. For example, to specify that the Expires value is a long past time, if you repeatedly press ENTER in the Address bar when you visit the network, you will repeat the visit each time: Expires:fri, Dec 1999 16:00:00 GMT
For example: Prohibit the page in IE cache
Strong>http Response message Header setting:
CacheControl = No-cache
Pragma=no-cache
Expires =-1
Expires is a good thing, if the Web page on the server often changes, set it to-1, indicating immediate expiration. If a page is updated daily 1 o'clock in the morning, you can set the expires to 1 o'clock in the morning the next day.
When the HTTP1.1 server specifies CacheControl = No-cache, the browser does not cache the Web page.
Legacy HTTP 1.0 Servers cannot use Cache-control headers.
Therefore, for backward compatibility with HTTP 1.0 servers, IE uses the Pragma:no-cache header to provide special support for HTTP.
Internet Explorer does not cache this response if the client communicates through a secure connection (https://)/with the server, and the server returns Pragma:no-cache headers in the response.
Note: Pragma:no-cache only prevents caching when used in a secure connection, and if used in an unsecured page, the processing is the same as expires:-1, and the page is cached but marked as immediately expired. The
Header common Directive
header is divided into three parts:
The first part is the HTTP protocol version (http-version);
The second part is state code (status);
Part III is divided into causal phrases (reason-phrase).
Copy Code code as follows:
//fix 404 Pages: Use this header directive to resolve the 404 header generated by the URL rewrite
header (' http/1.1 OK ');
//Set 404 Header: Page not found
header (' http/1.1 404 Not Found ');
//Page Permanent Redirect, you can tell the search engine to update their URLs
//Set Moved Permanently header (good for redrictions)
//Use with location header
header (' http/1.1 moved Permanently ');
//Access Limited
header (' http/1.1 403 Forbidden ');
//Server error
header (' http/1.1 Internal Server Error ');
//Redirect to a new location
//Redirect to a new location:
header (' location:http://www.www.jb51.net);
redirect
after a period of delay
//Redrict with delay:
header (' refresh:10; Url=http://www.jb51.net ');
print ' You'll be redirected in seconds ';
//Cover x-powered-by value
//override x-powered-by:php:
header (' x-powered-by:php/4.4.0 ');
header (' x-powered-by:brain/0.6b ');
//Content language (en = 中文版)
//Content language (en = 中文版)
header (' content-language:en ');
//Last modified (available at cache time)
//Last modified (good for caching)
$time = time ()-60; or Filemtime ($FN), etc
header (' last-modified: '. Gmdate (' d, D M Y h:i:s ', $time). ' GMT ');
//Tell the browser what to get is not yet updated
//header for telling the browser the content
//did not get changed
header (' http/1.1 304 not Modified ');
//Set the length of the content (available when cached):
//Set content length (good for caching):
header (' content-length:1234 ');
//used to download files:
//Headers for a download:
header (' Content-type:application/octet-stream ');
header (' content-disposition:attachment; filename= "Example.zip");
header (' content-transfer-encoding:binary ');
//Disable caching of current document:
//Load the file to Send:readfile (' example.zip ');
//Disable caching of the current document:
header (' Cache-control:no-cache, No-store, max-age=0, Must-revalidate ');
header (' Expires:mon, 1997 05:00:00 GMT ');
//Set Content type:
//Date in the Pastheader (' Pragma:no-cache ');
//Set Content type:
header (' content-type:text/html; charset=iso-8859-1 ');
header (' content-type:text/html; Charset=utf-8 ');
//Plain text file
header (' Content-type:text/plain ');
JPG Picture
header (' content-type:image/jpeg ');
//ZIP file
header (' Content-type:application/zip ');
//PDF file
header (' content-type:application/pdf ');
//Audio MPEG (MP3,...) file
header (' content-type:audio/mpeg ');
//Flash animation//show sign In box
header (' Content-type:application/x-shockwave-flash ');
//Display Login dialog box, which can be used for HTTP authentication
header (' http/1.1 401 Unauthorized ');
header (' Www-authenticate:basic realm= ' top Secret ');
print ' Text that'll be displayed if the user hits cancel or ';
print ' enters wrong login data ';