HTTP_*

      These variables are specific to requests made with HTTP.
      Interpretation of these variables may depend on the value of
      SERVER_PROTOCOL.

      Environment variables with names beginning with "HTTP_" contain
      header data read from the client, if the protocol used was HTTP.
      The HTTP header name is converted to upper case, has all
      occurrences of "-" replaced with "_" and has "HTTP_" prepended to
      give the environment variable name. The header data may be
      presented as sent by the client, or may be rewritten in ways which
      do not change its semantics. If multiple headers with the same
      field-name are received then they must be rewritten as a single
      header having the same semantics. Similarly, a header that is
      received on more than one line must be merged onto a single line.
      The server must, if necessary, change the representation of the
      data (for example, the character set) to be appropriate for a CGI
      environment variable.

      The server is not required to create environment variables for all
      the headers that it receives. In particular, it may remove any
      headers carrying authentication information, such as
      "Authorization"; it may remove headers whose value is available to
      the script via other variables, such as "Content-Length" and
      "Content-Type".

   PATH_INFO

      A path to be interpreted by the CGI script. It identifies the
      resource or sub-resource to be returned by the CGI script. The
      syntax and semantics are similar to a decoded HTTP URL `hpath'
      token (defined in RFC 1738 [4]), with the exception that a
      PATH_INFO of "/" represents a single void path segment. Otherwise,
      the leading "/" character is not part of the path.

         PATH_INFO = "" | "/" path
         path      = segment *( "/" segment )
         segment   = *pchar
         pchar     = <any CHAR except "/">





 
INTERNET-DRAFT       Common Gateway Interface - 1.1     15 February 1996


      The PATH_INFO string is the trailing part of the  component
      of the script URI that follows the SCRIPT_NAME part of the path.

   PATH_TRANSLATED

      The OS path to the file that the server would attempt to access
      were the client to request the absolute URL containing the path
      PATH_INFO.  i.e for a request of

         protocol "://" SERVER_NAME ":" SERVER_PORT enc-path-info

      where `enc-path-info' is a URL-encoded version of PATH_INFO. If
      PATH_INFO is NULL then PATH_TRANSLATED is set to NULL.

         PATH_TRANSLATED = *CHAR

      PATH_TRANSLATED need not be supported by the server. The server
      may choose to set PATH_TRANSLATED to NULL for reasons of security,
      or because the path would not be interpretable by a CGI script;
      such as the object it represented was internal to the server and
      not visible in the file-system; or for any other reason.

      The algorithm the server uses to derive PATH_TRANSLATED is
      obviously implementation defined; CGI scripts which use this
      variable may suffer limited portability.

   QUERY_STRING

      A URL-encoded search string; the  part of the script URI.

         QUERY_STRING = query-string
         query-string = *qchar
         qchar        = unreserved | escape | reserved
         unreserved   = alpha | digit | safe | extra
         reserved     = ";" | "/" | "?" | ":" | "@" | "&" | "="
         safe         = "$" | "-" | "_" | "." | "+"
         extra        = "!" | "*" | "'" | "(" | ")" | ","
         escape       = "%" hex hex
         hex          = digit | "A" | "B" | "C" | "D" | "E" | "F" | "a"
                      | "b" | "c" | "d" | "e" | "f"

      The URL syntax for a search string is described in RFC 1738 [4].

   REMOTE_ADDR

      The IP address of the agent sending the request to the server. Not
      necessarily that of the client.