What does php header mean?

The header function sends some header information in PHP. We can use it directly to do 301 jumps, etc. Below I will summarize the usage of the header function and some common questions. Solution.

Send a raw HTTP header [Http Header] to the client. The header is a string sent by the server before transmitting HTML data to the browser using HTTP protocol. A blank line is required between the header and the HTML file.

1. Direction.

Header("Location: http://www.mobiletrain.org");

exit; //"exit" must be added after each redirection to avoid continuing execution after an error occurs.

2. Disable page caching in IE

header( 'Expires: Mon, 26 Jul 1997 05:00:00 GMT' );
header( 'Last-Modified: ' . gmdate( 'D, d M Y H:i:s' ) . ' GMT' );
header( 'Cache-Control: no-store, no-cache, must-revalidate' );
header( 'Cache-Control: post-check=0, pre-check=0', false );
header( 'Pragma: no-cache' ); //兼容http1.0和https

3. Implement file download

header('Content-Type: application/octet-stream');//设置内容类型
header('Content-Disposition: attachment; filename="example.zip"'); //设置MIME用户作为附件下载 如果将attachment换成inline意思为在线打开
header('Content-Transfer-Encoding: binary');//设置传输方式
header('Content-Length: '.filesize('example.zip'));//设置内容长度
readfile('example.zip');//读取需要下载的文件

4. Send the Status header

header(”Status: 404 Not Found”);

to the browser, but I found that the response actually returned by the browser is:

// ok
header(‘HTTP/1.1 200 OK’);
//设置一个404头:
header(‘HTTP/1.1 404 Not Found’);
//设置地址被永久的重定向
header(‘HTTP/1.1 301 Moved Permanently’);
HTTP/1.x 200 OK
Date: Thu, 03 Aug 2006 07:49:11 GMT
Server: Apache/2.0.55 (Win32)php/5.0.5
X-Powered-By: PHP/5.0.5
Status: 404 Not Found
Content-Length: 0
Keep-Alive: timeout=15, max=98
Connection: Keep-Alive
Content-Type: text/html
注意事项有以下几点.

There cannot be a space between Location and ":", otherwise it will An error occurred (note: I just tested it. In my local environment, there was no page jump, but no error was reported, I don’t know the reason);

There cannot be any output before using the header (note: Everyone knows this. If there is any output before the header, including blanks, the error "header already sent by xxx" will appear);

Things after the header will still be executed.

Recommended: "PHP Tutorial"

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