CGI Environmental Variables

In addition to information which is transmitted through CGI variables (like dest, month and day in the previous example), a large amount of information is transfered to CGI programs through environmental variables. These variables can be accessed in your program in the usual way, that is, by using the eviron dictionary of the os module. Table 8.6 lists the names and meanings of some of these environmental variables.

Table 8.6: Some Environmental Variables Passed through CGI

Name	Contents
HTTP_COOKIE	Persistent data stored in cookies
HTTP_REFERER	URL of refering document
HTTP_USER_AGENT	Type of browser being used
QUERY_STRING	URL Fragment after ?
REMOTE_ADDR	IP Address of user
REMOTE_HOST	Hostname of user
REMOTE_USER	Username, if authentication was used
SERVER_NAME	Hostname of server
SERVER_PORT	Port number of server
SERVER_SOFTWARE	Name and version of server software