IIS server variables provide information about the server, the connection with the client, and the current request on the connection. IIS server variables are not the same as environment variables. Some server variables get their information from HTTP headers. It is recommended that you distrust information in HTTP headers because this data can be falsified by malicious users. For more detailed information, see Writing More Secure IIS Applications. Obtaining Server Variables Server variables can be obtained in one of the following ways: Variable Description ALL_ HTTPAll HTTP headers sent by the client. ALL_ RAWRetrieves all headers in raw form. The difference between ALL_ RAW and ALL_ HTTP is that ALL_ HTTP places an HTTP_ prefix before the header name and the header name is always capitalized. In ALL_ RAW the header name and values appear as they are sent by the client. APP_ POOL_ ID IIS 5.1 and earlier: This server variable is not available. Returns the name of the application pool that is running in the IIS worker process that is handling the request. There is also an APP_ POOL_ ID environment variable that is available to applications that are running in the IIS worker process. APPL_ MD_ PATHRetrieves the metabase path of the application. APPL_ PHYSICAL_ PATHRetrieves the physical path corresponding to the metabase path in APPL_ MD_ PATH. AUTH_ PASSWORDThe value entered in the client's authentication dialog. This variable is available only if Basic authentication is used. AUTH_ TYPEThe authentication method that the server uses to validate users when they attempt to access a protected script. It does not mean that the user was authenticated if AUTH_ TYPE contains a value and the authentication scheme is not Basic or integrated Windows authentication. The server allows authentication schemes it does not natively support because an ISAPI filter may be able to handle that particular.
Superglobals were introduced in PHP, and are built-in variables that are always available in all scopes. PHP Global Variables - Superglobals Several predefined variables in PHP are superglobals, which means that they are always accessible, regardless of scope - and you can access them from any function, class or file without having to do anything special. The PHP superglobal variables are: $ GLOBALS $_ SERVER $_ REQUEST $_ POST $_ GET $_ FILES $_ ENV $_ COOKIE $_ SESSION This chapter will explain some of the superglobals, and the rest will be explained in later chapters. PHP $ GLOBALS $ GLOBALS is a PHP super global variable which is used to access global variables from anywhere in the PHP script (also from within functions or methods). PHP stores all global variables in an array called $ GLOBALS[index]. The index holds the name of the variable. The example below shows how to use the super global variable $ GLOBALS: Example Run example » In the example above, since z is a variable present within the $ GLOBALS array, it is also accessible from outside the function! PHP $_ SERVER $_ SERVER is a PHP super global variable which holds information about headers, paths, and script locations. The example below shows how to use some of the elements in $_ SERVER: Example ; echo $_ SERVER[' SERVER_ NAME'];echo
;echo $_ SERVER[' HTTP_ HOST']; echo
;echo $_ SERVER[' HTTP_ REFERER'];echo
;echo $_ SERVER[' HTTP_ USER_ AGENT'];echo
;echo $_ SERVER[' SCRIPT_ NAME'];?> Run example » The following table lists the most important elements that can go inside $_ SERVER: Element/ Code Description $_ SERVER[' PHP_ SELF'] Returns the filename of the currently executing script $_ SERVER[' GATEWAY_ INTERFACE'] Returns the version of the Common.
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