GetServerVariable

Important:
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This function retrieves information about an HTTP connection or about IIS itself.

Some server variables, such as Request_Method and Content_Length are embedded in the EXTENSION_CONTROL_BLOCKstructure. You can use GetServerVariableto obtain information about the request or server that is not included in the EXTENSION_CONTROL_BLOCK.

BOOL WINAPI GetServerVariable( HCONN
hConn
, LPSTR
lpszVariableName
, LPVOID
lpvBuffer
, LPDWORD
lpdwSizeofBuffer
);

Parameters

hConn

Specifies the connection handle.

lpszVariableName

A null-terminated ANSI string that indicates which variable is requested. The following table lists the possible variables.

Variable	Description
ALL_RAW	Retrieves all headers in raw form. The header names and values appear as they are sent by the client. Currently, this value is primarily used by proxy servers and other similar applications.
AUTH_PASSWORD	Specifies the value entered in the client's authentication dialog. This variable is only available if Basic authentication is used.
AUTH_TYPE	Specifies the type of authentication used. If the string is empty, then no authentication is used. Possible values are Kerberos, user, SSL/PCT, Basic, and integrated Windows authentication.
AUTH_USER	Specifies the value entered in the client's authentication dialog box.
CONTENT_LENGTH	Specifies the number of bytes of data that the script or extension can expect to receive from the client. This total does not include headers.
CONTENT_TYPE	Specifies the content type of the information supplied in the body of a POST request.
HTTPS	Returns on if the request came in through secure channel (with SSL encryption), or off if the request is for an unsecure channel.
PATH_INFO	Specifies the additional path information, as given by the client. This consists of the trailing part of the URL after the script or ISAPI DLL name, but before the query string, if any.
PATH_TRANSLATED	Specifies this is the value of PATH_INFO, but with any virtual path expanded into a directory specification.
QUERY_STRING	Specifies the information that follows the first question mark in the URL that referenced this script.
REMOTE_ADDR	Specifies the IP address of the client or agent of the client (for example gateway, proxy, or firewall) that sent the request.
REMOTE_USER	Specifies the user name supplied by the client and authenticated by the server. This comes back as an empty string when the user is anonymous.
REQUEST_METHOD	Specifies the HTTP request method verb.
SCRIPT_NAME	Specifies the name of the script program being executed.
SERVER_NAME	Specifies the server's host name, or IP address, as it should appear in self-referencing URLs.
SERVER_PORT	Specifies the TCP/IP port on which the request was received.
SERVER_PORT_SECURE	Specifies a string of either 0 or 1. If the request is being handled on the secure port, then this will be 1. Otherwise, it will be 0.
SERVER_PROTOCOL	Specifies the name and version of the information retrieval protocol relating to this request.
SERVER_SOFTWARE	Specifies the name and version of the Web server under which the ISAPI extension DLL program is running.
URL	Specifies the base portion of the URL. Parameter values will not be included. The value is determined when IIS parses the URL from the header.

lpvBuffer

Points to the buffer to receive the requested information.

lpdwSizeofBuffer

Points to a DWORD that indicates the size of the buffer pointed to by lpvBuffer. On successful completion, the DWORD contains the size of bytes transferred into the buffer, including the null-terminating byte.

Return Values

If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. The GetLastErrorfunction can be used to determine why the call failed. The following are the possible error values.

Value	Description
ERROR_INVALID_PARAMETER	Bad connection handle, or invalid values, in either lpszVariableNameor lpdwSizeOfBuffer.
ERROR_INVALID_INDEX	Bad or unsupported variable identifier.
ERROR_INSUFFICIENT_BUFFER	Buffer too small. The required buffer size is * lpdwSizeofBuffer.
ERROR_NO_DATA	The data requested is not available.

Remarks

The GetServerVariablefunction copies information into a buffer supplied by the caller. The information can include CGI variables and information relating to an HTTP connection or to the server itself.

In respect to AUTH_TYPE, if the string is not empty it does not mean the user was authenticated (if 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 scheme.

The lpszVariableNamecan be used to retrieve a specific request (client) header by using the HTTP_ headernamevalue. For example, supplying the value HTTP_ACCEPT returns the Accept header, and HTTP_VERSION returns the Version header.

The values of the fields for the HTTP_ACCEPT variable are concatenated, and separated by a comma (,).

Requirements

Runs On	Versions	Defined in	Include	Link to
Windows CE OS	3.0 and later	httpext.h		Httpfilt.lib

Note This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.

See Also

GetLastError, EXTENSION_CONTROL_BLOCK