CGI Variable

Environment variables store network system information that a CGI program needed. Snaml environment variables can be accessed through env global array. For example,

set server_name $::env(SERVER_NAME) 
set server_software $::env(SERVER_SOFTWARE) 

Server information variables provide the server status. 'GATEWAY_INTERFACE' is the CGI revision of the server; 'SERVER_NAME' is the host name or IP address of the server; and'SERVER_SOFTWARE' is the name and version of server software. In additon, 'SERVER_PROTOCOL' is the name and revision of the protocol such as HTTP 1.0. Finally, 'SERVER_PORT' is the host port number

#!/usr/local/bin/snaml
__cgi "Content-type: text/html"
_html
_head 
  _title 
    _quote "Server Information"
  title_
head_
_body
  _pre
  _quote "GATEWAY_INTERFACE = $::env(GATEWAY_INTERFACE)"
  _quote "SERVER_NAME       = $::env(SERVER_NAME)"
  _quote "SERVER_SOFTWARE   = $::env(SERVER_SOFTWARE)"
  _quote "SERVER_PROTOCOL   = $::env(SERVER_PROTOCOL)"
  _quote "SERVER_PORT       = $::env(SERVER_PORT)"
  pre_
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Client sends its information to the server through the environment variables. 'HTTP_USER_AGENT' stores the name of a client browser. 'HTTP_USER_FROM' is the email address of a client. Unfortunately, most browsers does not support this property. In addition, 'HTTP_ACCEPT' is a list of MIME type that a client can recognize. 'HTTP_REFERER' is the URL of a client before its visiting. The tracing information of a visitor's URL is useful for statistics.

#!/usr/local/bin/snaml


__cgi "Content-type: text/html"
_html
_head 
  _title 
    _quote "Client Information" 
  title_ 
head_
_body
  _pre
  _quote "HTTP_USER_AGENT = $::env(HTTP_USER_AGENT)"
  _quote "HTTP_USER_FROM = $::env(HTTP_USER_FROM)"
  _quote "HTTP_ACCEPT = $::env(HTTP_ACCEPT)" 
  _quote "HTTP_REFERER = $::env(HTTP_REFERER)"
  pre_	
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Directory information variables provide path information. 'DOCUMENT_ROOT' is the root directory for a web document; 'PATH_INFO' is the extra path information to a CGI program; and 'PATH_TRANSLATED' is the path that maps PATH_INFO to the root directory. Finally 'SCRIPT_NAME' is the relative path name of a CGI script.

#!/usr/local/bin/snaml
__cgi "Content-type: text/html"
_html
_head
  _title
    _quote "Directory Information" 
  title_
head_
_body
  _pre
  _quote "DOCUMENT_ROOT     = $::env(DOCUMENT_ROOT)"
  _quote "PATH_INFO         = $::env(PATH_INFO)"
  _quote "PATH_TRANSLATED   = $::env(PATH_TRANSLATED)"
  _quote "SCRIPT_NAME       = $::env(SCRIPT_NAME)"
  pre_
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html_

#!/usr/local/bin/snaml
__cgi "Content-type: text/html"
_html
_head 
  _title
    _quote "Content Information" 
  title_
head_
_body
  _pre
  _quote "QUERY_STRING = $::env(QUERY_STRING)"
  _quote "CONTENT_TYPE = $::env(CONTENT_TYPE)"
  _quote "CONTENT_LENGTH = $::env(CONTENT_LENGTH)"
  pre_
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Authentication and Identification specify the method of authentication and the identification of user. 'AUTH_TYPE' stores the authentication method; 'REMOTE_HOST' and 'REMOTE_ADDR' are remote hostname and IP address; and 'REMOTE_USER' is user's name. Finally, 'REMOTE_IDENT' is the user name who makes request.

#!/usr/local/bin/snaml
__cgi "Content-type: text/html"
_html
_head
  _title
    _quote "Content Information" 
  title_ 
head_;
_body
  _pre
  _quote "AUTH_TYPE = $env(AUTH_TYPE)" 
  _quote "REMOTE_HOST = $env(REMOTE_HOST)"
  _quote "REMOTE_ADDR = $env(REMOTE_ADDR)"
  _quote "REMOTE_USER = $env(REMOTE_USER)"
  _quote "REMOTE_IDENT = $env(REMOTE_IDENT)" 
  pre_
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GET method makes form data contained in a URL string. POST method makes CGI program receive data as an input stream.