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118

Chapter 5 Accessing the Standard CGI Variables

REMOTE_HOST

REMOTE_HOST

 indicates the fully qualified domain name (e.g., 

white 

house.gov

) of the client that made the request. The IP address is 

returned if the domain name cannot be determined. You can access this 

variable with 

request.getRemoteHost()

.

REMOTE_USER

If an 

Authorization

 header was supplied and decoded by the server 

itself, the 

REMOTE_USER

 variable gives the user part, which is useful 

for session tracking in protected sites. Access it with 

request.get 

RemoteUser()

. For decoding 

Authorization

 information directly in 

servlets, see Section 4.5 (Restricting Access to Web Pages).

REQUEST_METHOD

This variable stipulates the HTTP request type, which is usually 

GET

 or 

POST

 but is occasionally 

HEAD

, 

PUT

, 

DELETE

, 

OPTIONS

, or 

TRACE

. Servlets 

rarely need to look up 

REQUEST_METHOD

 explicitly, since each of the 

request types is typically handled by a different servlet method (

doGet

, 

doPost

, etc.). An exception is 

HEAD

, which is handled automatically by 

the 

service

 method returning whatever headers and status codes the 

doGet

 method would use. Access this variable by means of 

request.getMethod()

.

SCRIPT_NAME

This variable specifies the path to the servlet, relative to the server's root 

directory. It can be accessed through 

request.getServletPath()

.

SERVER_NAME

SERVER_NAME

 gives the host name of the server machine. It can be 

accessed by means of 

request.getServerName()

.

SERVER_PORT

This variable stores the port the server is listening on. Technically, the 

servlet equivalent is 

String.valueOf(request.getServerPort())

, 

which returns a 

String

. You'll usually just want 

request.getServer 

Port()

, which returns an 

int

.

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