MACROMEDIA COLFUSION MX 7-CFML, Reference

Page: 17 / 1108

CGI environment variables 17
Server
CGI.GATEWAY_INTERFACE
CGI.SERVER_NAME
CGI.SERVER_PORT
CGI.SERVER_PROTOCOL
CGI.SERVER_SOFTWARE
Client
CGI.CERT_ISSUER
CGI.CERT_SUBJECT
CGI.CLIENT_CERT_ENCODED
CGI.HTTP_ACCEPT
CGI.HTTP_IF_MODIFIED_SINCE
CGI.HTTP_USER_AGENT
The
CERT_ISSUER
,
CERT_SUBJECT
,
CLIENT_CERT_ENCODED
variables are available only when you
use client certificates.
CGI environment variables
When a browser makes a request to a server, the web server and the browser create environment
variables. In ColdFusion, these variables are referred to as
CGI environment variables . They take
the CGI prefix regardless of whether the server uses a server API or CGI to communicate with the
ColdFusion server.
Environment variables contain data about the transaction between the browser and the server,
such as the IP Address, browser type, and authenticated username. You can reference CGI
environment variables for a given page request anywhere in the page. CGI variables are read-only.
Note: The environment variables available to applications depend on the browser and server
software.
Testing for CGI variables
Because some browsers do not support some CGI variables, ColdFusion always returns True
when it tests for the existence of a CGI variable, regardless of whether the browser supports the
variable. To determine if the CGI variable is available, test for an empty string, as shown in the
following example:
<cfif CGI. varname IS NOT "">
CGI variable exists
<cfelse>
CGI variable does not exist
</cfif>