Summary of header usage in PHP, summary of PHPheader usage_PHP tutorial

A summary of header usage in PHP, a summary of PHP header usage

The examples in this article summarize the usage of header in PHP. Share it with everyone for your reference, the details are as follows:

The header() function in PHP is to send header information to the client.

What is header information?

Here is only a brief explanation, please read the http protocol in detail.

In the HTTP protocol, the server-side response content includes two parts: header information (header) and body content. The header information here is not the part in HTML. Similarly, the body content The content is not < /BODY>. The header information is invisible to the user and contains many items, including server information, date, content length, etc. The body content is the entire HTML, which is everything you can see.

What is the use of header information?

Header information has many functions, the most important ones are the following:

1. Jump:

Header("Refresh:2; URL=http://localhost//session.php");//2秒后跳转

If the waiting time is 0, it is equivalent to header("location:").

Header("Location:http://localhost//session.php");//直接跳转

2. The content of the specified web page:

For the same XML file, if the header information specifies: Content-type: application/xml, the browser will parse it according to the XML file format. However, if the header information is: Content-type: text/xml, the browser will interpret it as stored text. (Browsers do not parse files according to extensions)

3. Attachment download:

$filename = "tupian.jpg"; //文件路径 可以绝对路径也可以相对路径
header('Content-type: application/x-jpg'); //文件的类型
header('Content-Disposition: attachment; filename="保存时的文件名.jpg"'); //下载显示的名字
readfile("$filename");
exit();

View:

$link = "tupian.jpg"; //文件路径 可以绝对路径也可以相对路径
//$link = "新建文本文档.xml"; //文件路径 可以绝对路径也可以相对路径
if (isset($link))
{
  Header("HTTP/1.1 303 See Other");
  Header("Location: $link");
  exit;
}

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I hope this article will be helpful to everyone in PHP programming.