Environment Variables

Environment variables are values passed to a program by the server on the system where the program is running. Common Gateway Interface (CGI) scripts, which perform such tasks as processing HTML forms, get their input mainly from environment variables. These environment variables are set when the server executes the gateway program. CGI scripts use environment variables to send your program its parameters.

URLs:

• CGI Environment Variables
• Common Gateway Interface
• Your Session Info (See Your Environment Variables!)

W3E References:

• CGI

Detail:

These are the CGI environment variables:

AUTH_TYPE

If the server supports user authentication, and the script is protected, this is the protocol-specific authentication method used to validate the user.

CONTENT_LENGTH

The length of the said content as given by the client.

CONTENT_TYPE

For queries which have attached information, such as HTTP POST and PUT, this is the content type of the data.

GATEWAY_INTERFACE

The revision of the CGI specification to which this server complies. Format: CGI/revision

PATH_INFO

The extra path information, as given by the client. Scripts can be accessed by their virtual pathname, followed by extra information at the end of this path. Decoded by the server.

PATH_TRANSLATED

The server provides a translated version of PATH_INFO, which takes the path and does any virtual-to-physical mapping to it.

QUERY_STRING

The information which follows the ? in the URL which referenced this script. It should not be decoded in any fashion.

REMOTE_ADDR

The IP address of the remote host making the request.

REMOTE_HOST

The hostname making the request. If the server does not have this information, it should set REMOTE_ADDR and leave this unset.

REMOTE_IDENT

If the HTTP server supports RFC 931 identification, then this variable will be set to the remote user name retrieved from the server.

REMOTE_USER

If the server supports user authentication, and the script is protected, this is the username they have authenticated as.

REQUEST_METHOD

The method with which the request was made. For HTTP, this is "GET", "HEAD", "POST", etc.

SCRIPT_NAME

A virtual path to the script being executed, used for self-referencing URLs.

SERVER_NAME

The server's hostname, DNS alias, or IP address as it would appear in self-referencing URLs.

SERVER_PORT

Port number to which the request was sent.

SERVER_PROTOCOL

The name and revision of the information protocol this request came in with.

SERVER_SOFTWARE

The name and version of the information server software answering the request (and running the gateway). Format: name/version