The php Function GetAllHeaders

The php function getallheaders is used to read all the headers of a request sent by the web server. This is a useful function for blocking caches and for understanding how the web browser is communicating with the web server. This article will discuss this php function in depth and also provide some real-world examples of how it can be used.

The function gets all the headers of a request and stores them in an associative array. The headers can then be accessed and displayed using the foreach loop. The associative array can also be sorted to easily locate a particular header. However, it is important to note that the getallheaders() function is only available when PHP is running as an Apache module.

In other cases, it is possible to read request headers from the $_SERVER superglobal variable. This is done by using the syntax $_SERVER['HTTP_*'] where * indicates the header name and hyphens (-) are replaced by underscores (_). This is useful when working with other servers such as IIS.

Another option is to use the sys_stdin stream input function to read the body of the request. This is a useful function because it will return a StreamInterface instance and is guaranteed to work in both SAPI and non-SAPI environments.