The Request Method, as supplied in the REQUEST_METHOD meta-variable,
   identifies the processing method to be applied by the script in
   producing a response.  The script author can choose to implement the
   methods most appropriate for the particular application.  If the
   script receives a request with a method it does not support it SHOULD
   reject it with an error (see section 6.3.3).

4.3.1.  GET

   The GET method indicates that the script should produce a document
   based on the meta-variable values.  By convention, the GET method is
   'safe' and 'idempotent' and SHOULD NOT have the significance of
   taking an action other than producing a document.

   The meaning of the GET method may be modified and refined by
   protocol-specific meta-variables.






 
RFC 3875                    CGI Version 1.1                 October 2004


4.3.2.  POST

   The POST method is used to request the script perform processing and
   produce a document based on the data in the request message-body, in
   addition to meta-variable values.  A common use is form submission in
   HTML [18], intended to initiate processing by the script that has a
   permanent affect, such a change in a database.

   The script MUST check the value of the CONTENT_LENGTH variable before
   reading the attached message-body, and SHOULD check the CONTENT_TYPE
   value before processing it.

4.3.3.  HEAD

   The HEAD method requests the script to do sufficient processing to
   return the response header fields, without providing a response
   message-body.  The script MUST NOT provide a response message-body
   for a HEAD request.  If it does, then the server MUST discard the
   message-body when reading the response from the script.

4.3.4.  Protocol-Specific Methods

   The script MAY implement any protocol-specific method, such as
   HTTP/1.1 PUT and DELETE; it SHOULD check the value of SERVER_PROTOCOL
   when doing so.

   The server MAY decide that some methods are not appropriate or
   permitted for a script, and may handle the methods itself or return
   an error to the client.

4.4.  The Script Command Line

   Some systems support a method for supplying an array of strings to
   the CGI script.  This is only used in the case of an 'indexed' HTTP
   query, which is identified by a 'GET' or 'HEAD' request with a URI
   query string that does not contain any unencoded "=" characters.  For
   such a request, the server SHOULD treat the query-string as a
   search-string and parse it into words, using the rules

      search-string = search-word *( "+" search-word )
      search-word   = 1*schar
      schar         = unreserved | escaped | xreserved
      xreserved     = ";" | "/" | "?" | ":" | "@" | "&" | "=" | "," |
                      "$"

   After parsing, each search-word is URL-decoded, optionally encoded in
   a system-defined manner and then added to the command line argument
   list.




 
RFC 3875                    CGI Version 1.1                 October 2004


   If the server cannot create any part of the argument list, then the
   server MUST NOT generate any command line information.  For example,
   the number of arguments may be greater than operating system or
   server limits, or one of the words may not be representable as an
   argument.

   The script SHOULD check to see if the QUERY_STRING value contains an
   unencoded "=" character, and SHOULD NOT use the command line
   arguments if it does.

5.  NPH Scripts

5.1.  Identification

   The server MAY support NPH (Non-Parsed Header) scripts; these are
   scripts to which the server passes all responsibility for response
   processing.