rfc1835.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

   brief description of the service (which is intended, among other
   things, to support the automated registration of the service by
   yellow pages directory services). All of these commands are required
   from a conforming WHOIS++ server.



























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------------------------------------------------------------------------

Short  Long Form                               Functionality
-----  ---------                               -------------
       COMMANDS        [ ':' HOLD ]          list valid WHOIS++ commands
                                             supported by this server

       CONSTRAINTS     [ ':' HOLD ]          List valid constraints
                                             supported by this server

       DESCRIBE        [ ':' HOLD ]          Describe this server,
                                             formating the response
                                             using a standard
                                             "Services" template

 '?'   HELP [<string>  [':' <cnstrnts>]]     System help, using a "Help"
                                             template

       LIST            [':' <cnstrnts>]      List templates supported
                                             by this system

       POLLED-BY       [ ':' HOLD ]          List indexing servers
                                             that are know to track
                                             this server

       POLLED-FOR      [ ':' HOLD ]          List information about
                                             what this server is
                                             tracking for

       SHOW <string>   [':' <cnstrnts>]      Show contents of templates
                                             specified

       VERSION         [ ':' HOLD ]          return current version of
                                             the protocol supported.

              Table I - Required WHOIS++ SYSTEM commands.

------------------------------------------------------------------------

   Below follows a descriptions for each command. Examples of responses
   to each command is in Appendix C.

2.2.1.1.  The COMMANDS command

   The COMMANDS command returns a list of commands that the server
   supports. The response is formatted as a FULL response.





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2.2.1.2.  The CONSTRAINTS command

   The CONSTRAINTS command returns a list of constraints and the values
   of those that the server supports. The response is formatted as a
   FULL response, where every constraint is represented as a separate
   record. The template name for these records is CONSTRAINT.  No
   attention is paid to handles. Each record has, as a minimum, the
   following two fields:

     - "Constraint", which contains the attribute name described -
       "Default", which shows the default value for this constraint.

   If the client is permitted to change the value of the constraint,
   there is also:

     - "Range" field, which contains a list of values that this
       server supports, as a comma separated list; Or, if the range
       is numerical, as a pair of numbers separated with a hyphen.

2.2.1.3.  The DESCRIBE command

   The DESCRIBE command gives a brief description about the server in a
   "Services" template. The result is formatted as a FULL response.

2.2.1.4.  The HELP command

   The HELP command takes an optional argument as subject to get help
   for.

2.2.1.5.  The LIST command

   The LIST command returns the name of the templates available on the
   server. The answer is formatted FULL format response.

2.2.1.6.  The POLLED-BY command

   The POLLED-BY command returns a list of servers and the templates and
   attribute names that those server polled as centroids from this
   server. The format is in FULL format with two attributes, Template
   and Field. Each of these is a list of names of the templates or
   fields polled.  An empty result means either that the server is not
   polled by anyone, or that it doesn't support indexing.









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2.2.1.7.  The POLLED-FOR command

   The POLLED-FOR command returns a list of servers that this server has
   polled, and the template and attribute names for each of those.  The
   answer is in FULL format with two attributes, Template and Field.  An
   empty result means either that the server is not polling anyone, or
   that it doesn't support indexing.

2.2.1.8.  The SHOW command

   The SHOW command takes a template name as argument and returns
   information about a specific template, formatted as a FULL response.
   The answer is formatted as a blank template with the requested name.

2.2.1.9.  The VERSION command

   The output format is a FULL response containg a record with template
   name VERSION. The record must have attribute name "Version", which
   value is "1.0" for this version of the protocol.  The record may also
   have the additional fields "Program-Name" and "Program-Version" which
   gives information about the server implementation if the server so
   desires.

2.2.2.  The Search Command

   A search command consists of one or more search terms, which might
   each have local constraints, followed by an optional colon with a set
   of global search constraints.

   Each attribute value in the WHOIS++ database is divided into one or
   more words separated by whitespace. Each search term operates on
   every word in the attribute value.

   Two or more search terms may be combined with boolean operators AND,
   OR or NOT (other than the implied AND between terms). The operator
   AND has higher precedence than the operator OR, but this can be
   changed by the use of parentheses.

   Search constraints that apply to every search term are specified as
   global constraints. Local constraints override global constraints for
   the search term they are bound to. The search terms and the global
   constraints are separated with a colon (':'). Additional global
   constraints are appended to the end of the search command delimited
   with a semicolon ';'.

   If different search constraints can not be fulfilled, or the
   combination of different search constraints is uncombinable, the
   server may choose to ignore some constraints, but still do the search



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   and return some records.

   The set of required constraints are summarized in Table III. The set
   of optional constraints are summarized in Table IV.

   As an option, the server may accept specifications for attributes for
   either inclusion or exclusion from a reply. Thus, users could specify
   -only- those attributes to return, or specific attributes to filter
   out, thus creating custom views.

2.2.2.1.  Format of a Search Term

   Each search term consists of one of the following:

     1) A search string, followed by an optional semicolon and set of
        semicolon-separated local constraints.

     2) A search term specifier (as listed in Table II), followed by a
        '=', followed by a search string, an optional semicolon and a
        set of semicolon-separate local constraints.

     3) An abbreviated search term specifier, followed by a search
        string, followed by an optional semicolon and set of
        semicolon-separated local constraints.

     4) A combination of attribute name, followed by '=', followed by
        a search string, followed by an optional semicolon and set of
        semicolon-separate local constraints.

   If no term identifier is provided, then the search will be applied to
   attribute values only. This corresponds to an identifier of VALUE.

   If a SEARCH-ALL specifier is used then the search will be applied to
   all template names, handles, attribute names and attribute values.

   When the user specifies the search term using the form:

             "<attribute_name> = <value>"

   this is considered to be an ATTRIBUTE-VALUE search.

   For discussion of the system reply format, and selecting the
   appropriate reply format, see section 2.4.








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     -------------------------------------------------------------------

     Valid specifiers:
     -----------------

      Name                                  Functionality
      ----                                  -------------

      ATTRIBUTE-VALUE [ ';' <constrnt>]*    allows combining
                                            attribute and value
                                            specifiers in one term.
      HANDLE          [ ';' <constrnt>]*    Confine search to handles.
      SEARCH-ALL      [ ';' <constrnt>]*    Search everything.
      TEMPLATE        [ ';' <constrnt>]*    Confine search to
                                            template names.
      VALUE           [ ';' <constrnt>]*    Confine search to attribute
                                            values. This is the default.

     (Note: The name HANDLE can be replaced with the shortname '!')

     Acceptable forms of a search specifier:
     ---------------------------------------

     1) <searchstring>  [';' <constraint>]*

     2) <specifier> = <searchstring> [';' <constraint>]*

     3) <shortspecifier> <searchstring>  [';' <constraint>]*

     4) <attribute_name> = <searchstring>  [';' <constraint>]*

     (Note: A <constraint> is a name of a valid local constraint.)

            Table II - Valid search command term specifiers.

     -------------------------------------------------------------------

2.2.2.2.  Format of a Search String

   Special characters that need to be quoted are preceeded by a
   backslash, '\'.

   Special characters are space ' ', tab, equal sign '=', comma ',',
   colon ':', backslash '\', semicolon ';', asterisk '*', period '.',
   parenthesis '()', square brackets '[]', dollar sign '$' and
   circumflex '^'.





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   If the search term is given in some other character set than ISO-
   8859-1, it must be specified by the constraint INCHARSET.

2.3.  WHOIS++ Constraints

   Constraints are intended to be hints or recommendations to the server
   about how to process a command. They may also be used to override
   default behaviour, such as requesting that a server not drop the
   connection after performing a command.

   Thus, a user might specify a search constraint as "SEARCH=exact",
   which means that the search engine is to perform an exact match
   search. It might also specify "LANGUAGE=Fr", which implies that the
   server should use French in fuzzy matches. It might also be able to
   issue system messages in French.

   In general, contraints take the form "<constraintname>=<value>", with
   <value> being one of a specified set of valid values. The notable
   exception is "HOLD", which takes no argument.

   All constraints can be used as a global constraint, but only a few
   can be used as local. See tables IV and V for information of which
   constraints can be local.

   The CONSTRAINTS system command is used to list the search constraints
   supported by an individual server.

   If a server cannot satisfy the specified constraint there will be a
   mechanism for informing the user in the reply, using system messages.
   In such cases, the search is still performed, with the the server
   ignoring unsupported constraints.