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ASID Working Group Patrik Faltstrom
Internet-Draft Tele 2
Expires: September 1997 Sima Newell
draft-ietf-asid-whoispp-01.txt Bunyip Information Systems Inc.
Replaces: RFC-1835 Leslie L. Daigle
Bunyip Information Systems Inc.
March 1997
Architecture of the Whois++ service
Status of this Memo
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its
areas, and its working groups. Note that other groups may also
distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other docu-
ments at any time. It is inappropriate to use Internet- Drafts as
reference material or to cite them other than as ``work in
progress.''
To learn the current status of any Internet-Draft, please check
the ``1id-abstracts.txt'' listing contained in the Internet-
Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net
(Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East
Coast), or ftp.isi.edu (US West Coast).
Distribution of this document is unlimited.
Abstract
This document describes Whois++, an extension to the trivial WHOIS
service described in RFC 954 to permit WHOIS-like servers to make
available more structured information to the Internet. We describe
an extension to the simple WHOIS data model and query protocol and a
companion extensible, distributed indexing service. A number of
options have also been added such as the use of multiple languages
and character sets, more advanced search expressions, structured data
and a number of other useful features. An optional authentication
mechanism for protecting all or part of the associated Whois++
information database from unauthorized access is also described.
Table of Contents
Part I - Whois++ Overview .................................
1.1. Purpose and Motivation ..............................
1.2. Basic Information Model .............................
1.2.1. Changes to the current WHOIS Model ................
1.2.2. Registering Whois++ servers .......................
1.2.3. The Whois++ Search Selection Mechanism ............
1.2.4. The Whois++ Architecture ..........................
1.3. Indexing in Whois++ .................................
1.4. Getting Help ........................................
1.4.1. Minimum HELP Required .............................
1.5. Options and Constraints .............................
1.6. Formatting Responses ................................
1.7. Reporting Warnings and Errors .......................
1.8. Privacy and Security Issues .........................
Part II - Whois++ Implementation ..........................
2.1. The Whois++ interaction model .......................
2.2. The Whois++ Command set .............................
2.2.1. System Commands ...................................
2.2.1.1. The COMMANDS command ............................
2.2.1.2. The CONSTRAINTS command .........................
2.2.1.3. The DESCRIBE command ............................
2.2.1.4. The HELP command ................................
2.2.1.5. The LIST command ................................
2.2.1.6. The POLLED-BY command ...........................
2.2.1.7. The POLLED-FOR command ..........................
2.2.1.8. The SHOW command ................................
2.2.1.9. The VERSION command .............................
2.2.2. The Search Command ................................
2.2.2.1. Format of a Search Term .........................
2.2.2.2. Format of a Search String .......................
2.3. Whois++ Constraints .................................
2.3.1. Required Constraints ..............................
2.3.2. Optional CONSTRAINTS ..............................
2.3.2.1. The SEARCH Constraint ...........................
2.3.2.2. The FORMAT Constraint ...........................
2.3.2.3. The MAXFULL Constraint ..........................
2.3.2.4. The MAXHITS Constraint ..........................
2.3.2.5. The CASE Constraint .............................
2.3.2.6. The AUTHENTICATE Constraint .....................
2.3.2.7. The NAME Constraint .............................
2.3.2.8. The PASSWORD Constraint .........................
2.3.2.9. The LANGUAGE Constraint .........................
2.3.2.10. The INCHARSET Constraint .......................
2.3.2.11. The INCHARSET Constraint .......................
2.3.2.12. The IGNORE Constraint ..........................
2.3.2.13. The INCLUDE Constraint .........................
2.4. Server Response Modes ...............................
2.4.1. Default Responses .................................
2.4.2. Format of Responses ...............................
2.4.3. Syntax of a Formatted Response ....................
2.4.3.1. A FULL format response ..........................
2.4.3.2. ABRIDGED Format Response ........................
2.4.3.3. HANDLE Format Response ..........................
2.4.3.4. SUMMARY Format Response .........................
2.4.3.5. SERVERS-TO-ASK Response .........................
2.4.4. System Generated Messages .........................
2.5. Compatibility with Older WHOIS Servers ..............
3. Miscellaneous .........................................
3.1. Acknowledgements ....................................
3.2. References ..........................................
3.3. Authors' Addresses ..................................
Appendix A - Some Sample Queries ..........................
Appendix B - Some sample responses ........................
Appendix C - Sample responses to system commands ..........
Appendix D - Sample Whois++ session .......................
Appendix E - System messages ..............................
Appendix F - The Whois++ Input Syntax .....................
Appendix G - The Whois++ Response Syntax ..................
Appendix H - Description of Regular expressions ...........
1. Part I - Whois++ Overview
1.1. Purpose and Motivation
The current NIC WHOIS service [HARR85] is used to provide a very
limited directory service, serving information about a small number
of Internet users registered with the DDN NIC. Over time the basic
service has been expanded to serve additional information and similar
services have also been set up on other hosts. Unfortunately, these
additions and extensions have been done in an ad hoc and
uncoordinated manner.
The basic WHOIS information model represents each individual record
as a Rolodex-like collection of text. Each record has a unique
identifier (or handle), but otherwise is assumed to have little
structure. The current service allows users to issue searches for
individual strings within individual records, as well as searches for
individual record handles using a very simple query-response
protocol.
Despite its utility, the current NIC WHOIS service cannot function as
a general White Pages service for the entire Internet. Given the
inability of a single server to offer guaranteed response or
reliability, the huge volume of traffic that a full scale directory
service will generate and the potentially huge number of users of
such a service, such a trivial architecture is obviously unsuitable
for the current Internet's needs for information services.
This document describes the architecture and protocol for Whois++, a
simple, distributed and extensible information lookup service based
upon a small set of extensions to the original WHOIS information
model. These extensions allow the new service to address the
community's needs for a simple directory service, yet the extensible
architecture is expected to also allow it to find applications in a
number of other information service areas.
Added features include an extension to the trivial WHOIS data model
and query protocol and a companion extensible, distributed indexing
service. A number of other options have also been added, like boolean
operators, more powerful search constraints and search methods. In
addition, the data has been structured to make both the client and
server elements of the dialogue more stringent and easily
parsed. An optional authentication mechanism for protecting all or
parts of the associated Whois++ information database from
unauthorized access is also briefly described.
The architecture of Whois++ allows distributed maintenance of
the directory contents and the use of the Whois++ indexing service
for locating additional Whois++ servers. Although a general overview
of this service is included for completeness, the indexing extensions
are described described separately in [WINDX].
It should be noted that Whois++ is not backward compatible with WHOIS.
1.2. The Whois++ Information Model
The Whois++ service is based on the use of information templates, which
consist of ordered sets of data elements (or attribute-value pairs).
It underlying recommendation is to use standardized templates where
available.
It is intended that adding structured template types to a server
and subsequently searching through information stored in templates
of a specified type should be simple tasks. The creation and use of
customized templates should also be possible with little effort, although
their use is discouraged where appropriate standardized templates exist.
Registration and schema definitions are done on an attribute by
attribute basis, so a client that receives a record parses the
record structure one attribute at a time. Because of this system,
the client does not need to know the structure of the whole record,
only individual attributes. If the client sees an unknown
attribute, it will skip that one and continue parsing the
subsequent attributes. A server that defines schemas can therefore
add its own unregistered attributes to a well-defined template type.
We also offer methods to allow the user to constrain searches to
desired attributes or template types, in addition to the existing
commands for specifying handles or simple strings.
It is expected that the minimalist approach we have taken will find
applications where the high cost of configuring and operating
traditional White Pages services can not currently be justified.
Note also that the architecture makes no assumptions about the search
and retrieval mechanisms used within individual servers. Operators
are free to use dedicated database formats, fast indexing software or
even provide gateways to other directory services to store and
retrieve information. The Whois++ server simply functions as a
known front end, offering a simple data model and communicating
through a well known port and query protocol. The format of both
queries and replies has been structured to allow the use of client
software for generating searches and displaying the results. At the
same time, some effort has been made to keep responses legible (to
some degree) by human users, both to ensure low entry cost and to
ease debugging.
The actual implemention details of an individual Whois++ search
engine are left to the imagination of the implementor. It is hoped
that the simple, extensible approach taken will encourage
experimentation and the development of improved search engines.
1.2.1. Changes to the current WHOIS Model
The current WHOIS service is based upon an extremely simple data
model. The NIC WHOIS database consists of a series of individual
records, each of which is identified by a single unique identifer
(the "handle"). Each record contains one or more lines of
information. Currently, there is no structure or implicit ordering of
this information, although each record is implicitly concerned
with information about a single user or service.
We have implemented two basic changes to this model. First, we have
structured the information within the database as collections of data
elements that are simple attribute/value pairs. Each individual record
contains a specified ordered set of these data elements.
Second, we have introduced the classing of database records into
template types. In effect, each record is based upon one template of a
specified set; each template contains a finite and specified number
of data elements. This classing allows users to limit searches
to specific collections of information, such as information about
users, services, abstracts of papers, or descriptions of software.
Since the data typing is done at the attribute level, not the template
level, it is also possible to add non-standard attributes to a
well-known template type.
As an addition to the model, we require that each individual Whois++
database on the Internet be assigned a unique handle, analogous to
the handle associated with each database record.
The Whois++ database structure is shown in Fig. 1.
______________________________________________________________________
| |
| + Single unique Whois++ server handle |
| |
| _______ _______ _______ |
| handle3 |.. .. | handle6 |.. .. | handle9 |.. .. | |
| _______ | _______ | _______ | |
| handle2 |.. .. | handle5 |.. .. | handle8 |.. .. | |
| _______ | _______ | _______ | |
| handle1 |.. .. | handle4 |.. .. | handle7 |.. .. | |
| |.. .. | |.. .. | |.. .. | |
| ------- ------- ------- |
| Template Template Template |
| Type 1 Type 2 Type 3 |
| |
| |
| |
| |
| Fig.1 - Structure of a Whois++ database. |
| |
| Notes: - Entire database is identified by a single unique Whois++ |
| serverhandle. |
| - Each record has a single unique handle. |
| - Each record has a specific set of attributes, which is |
| determined by the Template Type used. |
| - Each value associated with an attribute is a text string |
| of an arbitrary length. |
|______________________________________________________________________|
1.2.2. Registering Whois++ servers
We propose that individual database handles be registered through the
Internet Assigned Numbers Authority (the IANA), ensuring their
uniqueness. This will allow us to specify each Whois++ entry on the
Internet as a unique pair consisting of a server handle and a record
handle.
A unique registered handle is preferable to using the host's IP
address, since it is conceivable that the Whois++ server for a
particular domain may move over time. If we preserve the unique
Whois++ handle in such cases we have the option of using it for
resource discovery and networked information retrieval (see [IIIR]
for a discussion of resource and discovery and support issues).
Uniqueness of server handles can be guaranteed by registering them with
IANA.
We believe that organizing information around a series of such
templates will make it easier for administrators to gather and
maintain this information and thus encourage them to make such
information available. At the same time, as users become more
familiar with the data elements available within specific templates
they will be able to specify their searches better, and the service
will become more useful.
1.2.3. The Whois++ Search Selection Mechanism
The WHOIS++ search mechanism is intended to be extremely simple. A
search command comprises one required element and one optional
element. The first (required) element is a set of one or more search
terms. The second (optional) element is a colon followed by set of
one or more global constraints, which modify or control the search.
Within each search term, the user may specify the template type,
attribute, value or handle that any record returned must satisfy. Each
search term can have an optional set of local constraints that apply
only to that term.
A Whois++ database may be seen as a single collection of
typed records. Each search term specifies a further constraint that the
selected set of output records must satisfy. Each term may thus be
thought of as performing a subtractive selection, in the sense that
any record that does not fulfill the term is discarded from the result
set. Result sets can be further specified by supplying multiple search
terms, related by logical connectives (AND, OR, NOT).
1.2.4. The Whois++ Architecture
The Whois++ directory service has an architecture which is separated
into two components: the base level server, which is described in
this paper, and an indexing server (described in [WINDX]). A single
physical server can act as both a base level server and an indexing server.
A base level server is one which contains only filled templates. An
indexing server is one which contains forward knowledge (q.v.) and
pointers to other indexing servers or base level servers.
1.3. Indexing in Whois++
Indexing in Whois++ is used to tie together many base level servers
and index servers into a unified directory service. For more detailed
information on this subject, see [WINDX].
Each base level server and index server that is to participate
in the unified directory service must generate forward knowledge
for the entries it contains. One type of forward knowledge is the
"centroid".
An example of a centroid is as follows. Consider a Whois++ server
that contains exactly three records:
Record 1 Record 2
Template: Person Template: Person
First-Name: John First-Name: Joe
Last-Name: Smith Last-Name: Smith
Favourite-Drink: Labatt Beer Favourite-Drink: Molson Beer
Record 3
Template: Domain
Domain-Name: foo.edu
Contact-Name: Mike Foobar
the centroid for this server would be
Template: Person
First-Name: Joe
John
Last-Name: Smith
Favourite-Drink:Beer
Labatt
Molson
Template: Domain
Domain-Name: foo.edu
Contact-Name: Mike
Foobar
An index server would then collect this centroid for this server as
forward knowledge.
Index servers can collect forward knowledge for any servers it
polls. In effect, all of the servers that the index server knows
about can be searched with a single query to the index server; the
index server holds the forward knowledge along with pointers to the
servers it indexes, and can refer the query to servers which might
hold information which satisfies the query.
Implementors of this protocol are strongly encouraged to incorporate
centroid generation abilities into their servers.
Whois++ uses the Common Indexing Protocol, which was originally described
in [WINDX] as a centroid-like object to provide index information
(forward knowledge) about server contents. This work is being extended in
the IETF's FIND Working-Group.
-------------------------------------------------------------------
____ ____
top level | | | |
whois index | | | |
servers ---- ----
/ \________ /
/ \ /
____ ____
first level | | | |
whois index | | | |
servers ---- ----
/ / \
/ / \
____ ____ ____
individual | | | | | |
whois servers | | | | | |
---- ---- ----
Fig. 2 - Indexing system architecture.
-------------------------------------------------------------------
1.4. Getting Help
Another extension to the basic WHOIS service is the requirement that
all servers support at least a minimal set of help commands, allowing
users to find out information about both the individual server and
the entire Whois++ service itself. This is done in the context of the
new extended information model by defining two specific template
formats and requiring each server to offer at least one example of
each record using these formats. The operator of each Whois++ service
is therefor expected to have, as a minimum, a single example of
SERVICES and HELP records, which can be accessed through appropriate
commands.
1.4.1. Minimum HELP Required
Executing the command:
DESCRIBE
gives a brief information about the Whois++ server.
Executing the command:
HELP
gives a brief description of the Whois++ service itself.
The text of both required helped records should contain pointers to
additional help subjects that are available.
Executing the command:
HELP <searchstring>
gives information on <searchstring>.
1.5. Options and Constraints
The Whois++ service is based upon a minimal core set of commands and
controlling constraints. A small set of additional optional commands
and constraints can be supported by a server. These allow users to
perform such tasks as provide security options, modify the
information contents of a server or add multilingual support. The
required set of Whois++ commands are listed in section 2.2.
Whois++ constraints are described in section 2.3. Optional
constraints are described in section 2.3.2.
1.6. Formatting Responses
The output returned by a Whois++ server is structured to allow
machine parsing and automated handling. Of particular interest is the
ability to return summary information about a search instead of having
to return the entire results.
All output of searches will be returned in one of five output
formats, which will be one of FULL, ABRIDGED, HANDLE, SUMMARY or
SERVER-TO-ASK. Note that a conforming server is only required to
support the FULL format.
When available, SERVER-TO-ASK format is used to indicate that a
search cannot be completed but that one or more alternative Whois++
servers may be able to perform the search.
Details of each output format are specified in section 2.4.
1.7. Reporting Warnings and Errors
The formatted response of Whois++ commands allows the encoding of
warning or error messages to simplify parsing and machine handling.
The syntax of output formats are described in detail in section 2.4,
and details of Whois++ warnings and error conditions are given in
Appendix E.
All system messages are numerical, but can be tagged with text. It is
the client's decision if the text is presented to the user.
1.8. Privacy and Security Issues
The basic Whois++ service was conceived as a simple, unauthenticated
information lookup service, but there are occasions when
authentication mechanisms are required. To handle such cases, one
optional mechanism is provided for authenticating each Whois++
transaction. This is the ability to name a (mutually-recognized)
authentication scheme in the optional AUTHENTICATE global constraint.
The one currently defined authentication scheme is PASSWORD, which
uses simple password authentication. Any other scheme name used must
begin with the characters "X-" and should thus be regarded as
experimental and non-standard.
Note that the Whois++ authentication mechanism does not dictate the
actual authentication scheme used, it merely provides a framework for
indicating that a particular transaction is to be authenticated, and
the appropriate scheme to use. This mechanism is extensible and
individual implementors are free to add additional schemes.
This document describes a very simple authentication scheme in which a
combination of username and password is sent together with the search
string so the server can verify that the user have access to the
information. Note that this is NOT by any means a method recommended
to secure the data itself because both password and information are
transferred unencrypted over the network.
Other, more sophisticated security and authentication schemes may
be proposed to address specific needs. For example, the Simple
Authentication and Security Layer (SASL) work proposed by John Myers
(particularly for POP and IMAP) may be applicable here.
2. Part II - Whois++ Implementation
2.1. The Whois++ interaction model
The Whois++ service has an assigned port number -- number 63.
However, there is nothing inherent the Whois++ protocol or interaction
model that prevents it from being used on any TCP connection on
any port -- the specification of the connection is outside the scope
of this protocol spec. Once a connection is established, the
server issues a banner message, and listens for input. The command
specified in this input is processed and the results returned
including an ending system message. If the client
does not specify the optional HOLD constraint, the connection is
then terminated.
If the server supports the optional HOLD constraint, and this
constraint is specified as part of any command, the server continues
to listen on the connection for another (single) line of input.
This cycle continues as long as the sender continues to append the
required HOLD constraint to each subsequent command.
2.2. The Whois++ Command set
The Whois++ command set consists of a core set of required systems
commands, a single required search command and an set of optional
system commands which support features that are not required by all
servers. The set of required Whois++ system commands are listed in
Table I. Valid search terms for the search command
are described in Table II.
Each Whois++ command also allows the use of one or more controlling
constraints, which, when selected, are used to override defaults or
otherwise modify the server's behavior. There is a core set of
constraints that must be supported by all conforming servers:
SEARCH (which controls the type of search performed), FORMAT (which
determines the output format used) and MAXHITS (which determines the
maximum number of matches that a search can return). These required
constraints are summarized in Table III.
An additional set of optional constraints are used to provide support
for different character sets, provide data for the authentication
scheme, and requesting multiple transactions during a single communications
session. These optional constraints are listed in Table IV.
It is possible, using the required COMMANDS and CONSTRAINTS system
commands, to query any Whois++ server for its list of supported
commands and constraints.
Please note that the line terminator is defined as a carriage
return and line feed (CR/LF) pair. Also, none of the commands or
constraints supported by Whois++ are case sensitive. For example,
the following are equivalent: HELP, Help, help, hElp.
Capitalization of all letters (e.g. HELP) is used only to improve
the legibility of this document. Finally, "attribute value" is
defined as "the value associated with an attribute".
2.2.1. System Commands
System commands are commands to the server for information or to
control its operation. These include commands to list the template
types available from individual servers, to obtain a single blank
template of any available type, and commands to obtain the list of
valid commands and constraints supported on a server.
There are also commands to obtain the current version of the Whois++
protocol supported, to access a simple help subsystem, to obtain a
brief description of the service provided by the Whois++
server. The DESCRIBE command is intended, among other
things, to support the automated registration of the service in
yellow pages directory services. The required commands are listed
in Table I.
------------------------------------------------------------------------
Short Long Form Functionality
----- --------- -------------
COMMANDS [ ':' HOLD ] List 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> [':' (<othercnstrnts> / HOLD)
0*(';' (<otherconstraints> / HOLD))]]
Provide help specific to this
Whois++ server, using a
"Help" template
LIST [':' (<othercnstrnts> / HOLD)
0*(';' (<otherconstraints> / HOLD))]
List templates supported
by this server
POLLED-BY [ ':' HOLD ] List indexing servers
that are known to poll
this server
POLLED-FOR [ ':' HOLD ] List information about
servers this server polls
SHOW <string> [':' <cnstrnts>] Show contents of template
specified in <string>
VERSION [ ':' HOLD ] Show the version of
the protocol supported by
this server
Table I - Required Whois++ SYSTEM commands.
------------------------------------------------------------------------
Below follows a descriptions for each command. Examples of responses
to each command are provided 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.
2.2.1.2. The CONSTRAINTS command
The CONSTRAINTS command returns a list of both the constraints and
their values 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 attributes:
- "Constraint", whose value is the constraint name
- "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", 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.
Note that, irrespective of whether a session is continued (with the HOLD
constraint) or not, constraints are set to the default value unless
explicitly changed with a constraint in each query.
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 with
as a minimum one attribute:
- "Text", which describes the service in a form legible by human users.
2.2.1.4. The HELP command
The HELP command takes an optional argument which is the subject on
which to get help. The answer is formatted as a FULL format response.
2.2.1.5. The LIST command
The LIST command returns the name of the templates available on the
server. The answer is formatted as a 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 servers polled as centroids from this
server. The format is in FULL format with two attributes, "Template"
and "Field", whose values are lists of the names of the polled
templates and fields, respectively. An empty result means either
that the server is not polled by anyone, or that it doesn't support
indexing.
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 that 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", whose
value is "2.0" 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.
If the server also supports the earlier version of the protocol,
"1.0", two records are given back as a response to the VERSION
command, one for each version supported.
2.2.2. The SEARCH Command
A SEARCH command comprises one required element and one optional
element. The first (required) element is a set of one or more search
terms. The second (optional) element is a set of global constraints,
which modify or control the search. Each search term can have an
optional set of local constraints that apply only to that term.
Each attribute value in the Whois++ database is divided into one or
more words separated by whitespace (see Appendix F for a definition
of whitespace) . Each search term operates on every word in the attribute
value.
Two or more search terms have to be combined with boolean operators AND,
OR or NOT. The operator AND has higher precedence than the operator OR,
but this can be changed by the use of parentheses.
Boolean operators function as follows for two search terms, A and
B. Let A1 be the result set from the first search term and B1 be the
result set from the second search. The operation A AND B returns the
hits in the intersection of sets A1 and B1. The operation A OR B
returns the hits in the union of the sets A1 and B1. The operation
NOT A returns all possible results that are not in set A1. The
behaviour of the boolean operators can be generalized to N search
terms where N > 2. Note that NOT has a higher precedence than AND
or OR, so NOT A AND B returns the hits in B that are not in A.
Search constraints that apply to all search terms 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 (':'). Each additional global
constraint is appended to the end of the search command, and a
semicolon ';' is used as the delimiter between global constraints.
If any of the search constraints can not be fulfilled, or if
several of the specified constraints are mutually exclusive, the
server ignores the constraints that can not be fulfilled and those
that are mutually exclusive. The server performs the search using
only the remaining constraints and returns the corresponding set of
records.
The set of required constraints are listed in Table III. The set
of optional constraints are listed in Table IV.
As an option, the server may accept specifications for attributes
to be included or excluded 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 set of semicolon-
separated local constraints. If local constraints are
specified, they are separated from the search string by a
semicolon. This is noted as:
<value> [';' <constraint>]*
2) A search term specifier (as listed in Table II), followed by a
'=', followed by a search string, an optional set of
semicolon-separated local constraints. If local constraints are
specified, they are separated from the search string by a
semicolon. This is noted as:
<specifier> = <value> [';' <constraint>]*
3) An attribute name, followed by '=', followed by
a search string, followed by an optional set of
semicolon-separate local constraints. If local constraints are
specified, they are separated from the search string by a
semicolon.
<attribute_name> = <value> [';' <constraint>]*
(Note: A <constraint> is a valid local constraint specification.)
If no search term specifier is provided, then the search will be
applied to attribute values only. This corresponds to an identifier
of VALUE.
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.
-------------------------------------------------------------------
Valid specifiers:
-----------------
Name Functionality
---- -------------
HANDLE Confine search to handles.
VALUE Confine search to attribute
values.
(Note: The specifier HANDLE= can be replaced with the shorthand '!')
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 '^'.
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. The user might also specify "LANGUAGE=Fr", which means that the
server should (if possible) display the French versions of the attribute
values, and if possible use French in fuzzy matches. The server should also
issue system messages in French.
In general, constraints take the form "<constraintname>=<value>", where
<value> is 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 (i.e., on the
whole query transaction). Only a few can be used as a constraint
local to a search term. See tables III and IV for information about 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, the server should
indicate this to the user through the use of system messages.
In such cases, the search is still performed, with the the server
ignoring unsupported constraints.
2.3.1. Required Constraints
The following CONSTRAINTS must be supported in all conforming Whois++
servers.
------------------------------------------------------------------
Format LOCAL/GLOBAL
------ -------------
SEARCH= exact / lstring LOCAL/GLOBAL
FORMAT= full / abridged / handle / summary GLOBAL
MAXHITS= 1-<max-allowed> GLOBAL
Table III - Required Whois++ constraints.
------------------------------------------------------------------
2.3.2. Optional CONSTRAINTS
The following CONSTRAINTS and constraint values are not required of a
conforming Whois++ server, but may be supported. If supported, their
names and supported values must be returned in the response to the
CONSTRAINTS command.
---------------------------------------------------------------------
Format LOCAL/GLOBAL
------ -------------
SEARCH= regex / fuzzy / substring LOCAL/GLOBAL
CASE= ignore | consider LOCAL/GLOBAL
FORMAT= server-to-ask GLOBAL
MAXFULL= 1-<max-allowed> GLOBAL
AUTHENTICATE= password GLOBAL
NAME= <string> GLOBAL
PASSWORD= <string> GLOBAL
INCHARSET= us-ascii / iso-8859-* /
UNICODE-1-1-UTF-8 / UNICODE-2-0-UTF-8 GLOBAL
OUTCHARSET= us-ascii / iso-8859-* /
UNICODE-1-1-UTF-8 / UNICODE-2-0-UTF-8 GLOBAL
LANGUAGE= <As defined in ISO 639:1988> GLOBAL
HOLD GLOBAL
IGNORE= <attributelist> GLOBAL
INCLUDE= <attributelist> GLOBAL
Table IV - Optional Whois++ constraints.
----------------------------------------------------------------------
2.3.2.1. The SEARCH Constraint
The SEARCH constraint is used for specifying the method that is to be
used for the search. The default method is "exact". Following is a
definition of each search method.
exact The search will succeed for a word that exactly
matches the search string.
substring The search will succeed for a word that matches
a part of a word.
regex The search will succeed for a word when a regular
expression matches the searched data. Regular
expression is built up by using constructions of
'*', '.', '^', '$', and '[]'. For use of
regular expressions see Appendix H.
fuzzy The search will succeed for words that matches the
search string by using an algorithm designed to catch
closely related names with different spelling, e.g.
names with the same pronunciation. The server
chooses which algorithm to use, but it may vary
depending on template name, attribute name and
language used (see Constraint Language above).
lstring The search will succeed for words that begins
with the search string.
2.3.2.2. The FORMAT Constraint
The FORMAT constraint describes what format the result will be in.
Default format is FULL. For a description of each format, see Server
Response Modes below.
2.3.2.3. The MAXFULL Constraint
The MAXFULL constraint sets the limit of the number of matching
records the server allows before it enforces SUMMARY responses. The
client may attempt to override this value by specifying another value
to that constraint. Example: If, for privacy reasons, the server is to
return the response in SUMMARY format if the number of hits exceeds
2, the MAXFULL constraint is set to 2 by the server.
Regardless of what format the client asked for, the server will change the
response format to SUMMARY when the number of matching records equals or
exceeds this value.
2.3.2.4. The MAXHITS Constraint
The MAXHITS constraint sets the maximum number of records returned to the
client in response to a query.
2.3.2.5. The CASE Constraint
The CASE constraint defines if the search should be case
sensitive or not. Default value is to have case ignored.
2.3.2.6. The AUTHENTICATE Constraint
The AUTHENTICATE constraint describes which authentication scheme to
use when executing the search. Depending on the authentication scheme
used, some other constraints may have to be specified. The authentication
scheme definition identifies which constraints it requires.
The only authentication scheme described in this document is
"password". If used, also the two other constraints "name" and
"password" need to be set.
2.3.2.7. The NAME Constraint
The NAME constraint is only used together with some authentication
scheme named by the constraint "authenticate".
With the password authentication scheme, this is expected to be a string
of characters representing a username, for which the specified password
should be verified (i.e., similar to the UNIX login program).
2.3.2.8. The PASSWORD Constraint
The PASSWORD constraint is only used together with some
authentication scheme named by the constraint "authenticate".
The password authentication scheme requires that the password associated
with the username be supplied by this constraint. The server
can use that pair of strings to do a simple authentication check,
similar to the UNIX login program.
2.3.2.9. The LANGUAGE Constraint
The LANGUAGE constraint specifies the language in which the client
wishes to receive responses. It therefore specifies which attribute
values should be presented to the user (i.e., only those in the specified
language, or for which no language information is available).
It can also be used as an extra information to the fuzzy matching search
method, and it might also be used to tell the server to give the system
responses in another language. This should preferably be handled by
the client. The language codes defined in RFC 1766 [ALVE95] should be
used as a value for the language constraint. In these, the case of
the letters are insignificant.
If a record has attribute values in different languages, and no LANGUAGE
search constraint was given in the query, the switch between the
different languages should be given in the response by the use
of system messages 601 which has one argument only, the name of the
language or one of the predefined strings "ANY" or "DEF". A block
of alternative attribute values starts with a language definition
like "% 601 SE". After the first language specification, zero or
more language specifications can be given, each switching into the
desired language. When all specific languages have been tagged, the
specification "% 601 DEF" can be used for specifying default attribute
values. A block of alternative attributes must end with "% 601 ANY".
The following is an example of a response using the language messages:
# FULL USER LOCAL USER-DOE
% 601 FR
Name: Monsieur John Doe
% 601 SV
Name: Herr John Doe
% 601 DEF
Name: Mister John Doe
% 601 ANY
Email: jdoe@doe.pp.se
# END
The language specifications may be suppressed by the server (using
the % 601 messages) if the client has explicitly, by using the global
constraint LANGUAGE, asked for a specific language.
2.3.2.10. The INCHARSET Constraint
The INCHARSET constraint tells the server in which character set the
search string itself is given. The default character set is ISO-
8859-1.
2.3.2.11. The OUTCHARSET Constraint
The OUTCHARSET constraint tells the server in which character set the
search result is supposed to be given in. The default character set is
ISO-8859-1, but the server may choose something else.
2.3.2.12. The IGNORE Constraint
The IGNORE constraint specifies which attributes NOT to include in
the result. All other attributes will be included (as if named
explicitly by the "include" constraint).
If an attribute is named both with the "include" and "ignore"
constraint, the attribute is to be included in the result, but the
system message "% 112 Requested constraint not fulfilled" must be
sent.
2.3.2.13. The INCLUDE Constraint
The INCLUDE constraint specifies which attributes to include in the
result. All other attributes will be excluded (as if named explicitly
by the "ignore" constraint).
If an attribute is named both with the "include" and "ignore"
constraint, the attribute is to be included in the result, but the
system message must be "% 112 Requested constraint not fulfilled".
2.3.2.14. The HOLD Constraint
The HOLD constraint requests that the server hold open the connection
after sending the response to the query. The server waits for another
user input string.
2.4. Server Response Modes
The grammar for Whois++ responses is given in Appendix G, and described
below.
There are currently a total of five different response modes possible
for Whois++ servers. These are FULL, ABRIDGED, HANDLE, SUMMARY and
SERVER-TO-ASK. The syntax of each output format is specified in more
detail in Appendix G.
1) A FULL format response provides the complete contents of a
template matching the specified query, including the template
type, the server handle and an optional record handle.
2) An ABRIDGED format response provides a brief summary, including
(as a minimum) the server handle, the corresponding record handle
and relevant information for that template.
3) A HANDLE format response returns a line with information about
the server handle and record handle for a record that matched
the specified query.
4) A SUMMARY response provides only a brief summary of information
the number of matches and the list of template types in which the
matches occurred.
5) A SERVER-TO-ASK response only returns pointers to other index
servers which might possibly be able to answer the specified
query.
The server may optionally respond with an empty result set and may also
respond with an empty response together with a system message to indicate
that the query was too complex for it to fulfill.
2.4.1. Default Responses
By default, a Whois++ server will provide FULL responses. This may be
changed by the client with the use of the global constraint "format".
The server will not respond with more matches than the value
specified with the global constraint "maxhits" in any response
format. If the number of matches exceeds this value, the server will
issues the system message 110 (maxhits value exceeded), but will
still show the responses, up to the number of the "maxhits"
constraint value. This mechanism will allow the server to hide the
number of possible matches to a search command.
2.4.2. Format of Responses
Each response consists of a numerical system generated message, which
can be tagged with text, followed by an optional formatted response
message, followed by a second system generated message. The formatted
response itself can include system messages, for example for switches in
language.
That is:
'%' <system messages> <nl>
[ <formatted response> ]
'%' <system messages> <nl>
If there are no matches to a query, the system is not required to
generate any output as a formatted response, although it must still
generate system messages.
For information about the standard text for system messages, see
Appendix E.
2.4.3. Syntax of a Formatted Response
All formatted responses except for the HANDLE response, consist of a
response-specific START line, followed by an optional response-
specific data section, followed by a TERMINATION line. The HANDLE
response is different in that it only consists of a START line. It
is permissible to insert any number of lines consisting solely of
CR/LF pairs within a formatted response to improve readability.
Each line shall be limited to no more than 81 characters, including
the terminating CR/LF pair. If a line (including the required leading
single space) would exceed 81 characters, it must be broken into
lines of no more than 81 characters, with each continuation line
beginning with a "+" character in the first column instead of the
leading character.
If an attribute value in a data section includes a line break, the
line break must be replaced by a CR/LF pair and the following line
begin with a "-" character in the first column, instead of the
leading character. The attribute name is not repeated on consecutive
lines.
A TERMINATION line consists of a line with a '#' in the first column,
followed by one space (ASCII 32) character, followed by the keyword END,
followed by zero or more characters, followed by a CR/LF pair.
A response-specific section will be one of the following:
1) FULL Format Response
2) ABRIDGED Format Response
3) HANDLE Format Response
4) SUMMARY Format Response
5) SERVER-TO-ASK Format Response
2.4.3.1. A FULL format response
A FULL format response consists of a series of responses, each
consisting of a START line, followed by the complete template
information for the matching record and a TERMINATION line.
Each START line consists of a '#' in the first column, followed by
one space character, the word "FULL", a space character,
the name of the corresponding template type, one space
character, the server handle, a space character, (optionally) the
handle for the record, and a terminating CR/LF pair.
The template information for the record will be returned as a series
of lines consisting of a single space, followed by the corresponding
line of the record.
The line of the record shall consist of a single space and the
attribute name followed by a ':', a single space, the value of that
attribute, and a CR/LF pair.
2.4.3.2. ABRIDGED Format Response
Each ABRIDGED format response consists of a START line, a single line
excerpt of the template information from each matching record and a
TERMINATION line. The excerpt information shall include information
that is relevant to the template type.
The START line consists of a '#' in the first column, followed by one
space character, the word "ABRIDGED", a space character,
the name of the corresponding template type, a space character,
the server handle, a space character, the handle for the
record, and a terminating CR/LF pair.
The abridged template information will be returned as a line,
consisting of a single space, followed by the abridged line of the
record and a CR/LF pair.
2.4.3.3. HANDLE Format Response
A HANDLE response consists of a single START line, which shall start
with a '#' in the first column, followed by one space
character, the word "HANDLE", a space character, the name of
the corresponding template, a space character, the handle for
the server, a space character, the handle for that record, and
a terminating CR/LF pair.
2.4.3.4. SUMMARY Format Response
A SUMMARY format response consists of a single response,
consisting of a line listing the number of matches to the specified
query, optionally a count of referrals, followed by a list of all template
types which satisfied the query at least once.
The START line shall begin with a '#' in the first column, be
followed by one white space character, the word "SUMMARY", a white
space character, the handle for the server, and a terminating
CR/LF pair.
The format of the attributes in the SUMMARY format follows the
rules for the FULL template, with the attributes "matches",
"referrals" and "templates". "matches" and "templates" are
mandatory, "referrals" optional.
The first line must begin with the string "matches:", be
followed by a space and the number of responses to the query and
terminated by a CR/LF pair.
The following line shall either begin with the string "templates: "
or the string "referrals: ". The string "templates: " are followed
by a CR/LF separated list of the name of the template types
which matched the query. Each line following the first which
include the text "templates:" must begin with a '-' instead of
a space. The string "referrals: " is followed by the number of
referrals included in the number of hits.
2.4.3.5. SERVER-TO-ASK Response
A SERVER-TO-ASK response consists of information to the client about
a server to contact next to resolve a query. If the server has
pointers to more than one server, it will present additional SERVER-
TO-ASK responses.
The SERVER-TO-ASK response will consist of a START line and a number
of lines with attribute-value pairs, separated by CRLF. Each line is
indented with one space. The end of a SERVER-TO-ASK response is
indicated with a TERMINATION line.
Each START line consists of a '#' in the first column, followed by
one space character, the word "SERVER-TO-ASK", a space
character, the handle of the server and a terminating CR/LF pair.
1. "Server-Handle" - The server handle of the server pointed at.
(req.)
2. "Host-Name" - Hostname for the server pointed at.
3. "Host-Port" - Portnumber for the server pointed at.
4. "Protocol" - The protocol to use when contacting this server. (opt.)
Other attributes may be present, depending on the index server.
The default protocol to use is Whois++.
2.4.4. System Generated Messages
All system generated messages must have a '%' as the first
character, a space as the second one, followed by a three digit
number, a space and an optional text message. The total length of the
line must be no more than 81 characters long, including the
terminating CR/LF pair. There is no limit to the number of system
messages that may be generated.
The format for multiline replies requires that every line, except the
last, begin with "%", followed by space, the reply code, a hyphen,
and an optional text. The last line will begin with "%", followed by
space, the reply code, a space and some optional text.
System generated messages displayed before or after the formatted
response section are expected to refer to operation of the system or
refer to the entire query. System generated messages within the
output of an individual record during a FULL response are expected to
refer to that record only, and could (for example) be used to
indicate problems with that record of the response. See Appendix E
for a description of system messages.
2.5. Compatibility with Older WHOIS Servers
Note that this format, although potentially more verbose, is still in
a human readable form. Responses from older systems that do not
follow this format are still conformant, since their responses would
be interpreted as being equivalent to optional text messages, without
a formatted response. Clients written to this specification would
display the responses as a advisory text message, where it would
still be readable by the user.
3. Miscellaneous
3.1. Acknowledgements
This document has been through many iterations of refinement, with
contributions of different natures along the way. These acknowledgements
accrue.
The Whois++ effort began as an intensive brainstorming session at the
24th IETF, in Boston Massachusetts. Present at the birth, and
contributing ideas through this early phase, were (alphabetically)
Peter Deutsch, Alan Emtage, Jim Fullton, Joan Gargano, Brad
Passwaters, Simon Spero, and Chris Weider. Others who have since
helped shape this document with feedback and suggestions include
Roxana Bradescu, Patrik Faltstrom, Kevin Gamiel, Dan Kegel, Michael
Mealling, Mark Prior and Rickard Schoultz.
Version 2 of the protocol is based on input during the lifetime of
version 1. Special mention goes to Jeff Allen, Leslie Daigle,
and Philippe Boucher. During the polishing of the RFC for version 2,
important input was given by Len Charest, Clarke Anderson and others
in the ASID working group of the IETF.
Work in the European ROADS project provided the opportunity to test this
protocol specification from the point of view of developing a test suite.
The challenge was not only to provide AN implementation that satisfied the
document, but to build tools that would be able to respond to all
POSSIBLE responses that could be implemented from the spec. This then
lead to the contribution of some textual clarifications. Specific thanks
go to Bill Heelan and Philippe Boucher.
3.2 References
[ALVE95] Alvestrand H., "Tags for the Identification of
Languages", RFC 1766, UNINETT, March 1995.
[RFC822] Crocker, D., "Standard for the Format of ARPA Internet
Text Messages", RFC 822, August 1982.
[HARR85] Harrenstein K., Stahl M., and E. Feinler,
"NICNAME/WHOIS", RFC 954, SRI, October 1985.
[POST82] Postel J., "Simple Mail Transfer Protocol", STD 10,
RFC 821, USC/Information Sciences Institute,
August 1982.
[IIIR] Weider C., and P. Deutsch, "A Vision of an
Integrated Internet Information Service", RFC 1727
Bunyip Information Systems, Inc., December 1994.
[WINDX] Weider, C., J. Fullton, and S. Spero, "Architecture of
the Whois++ Index Service", RFC 1913, February 1996.
3.3. Authors Addresses
Patrik Faltstrom
Tele2
Borgarfjordsgatan 16
BOX 62
194 64 Kista
SWEDEN
Email: paf@swip.net
Sima Newell
Bunyip Information Systems Inc.
310 Ste. Catherine St. W
Suite 300
Montreal, Quebec, CANADA
H2X 2A1
Email: sima@bunyip.com
Leslie L. Daigle
Bunyip Information Systems Inc.
310 Ste. Catherine St. W
Suite 300
Montreal, Quebec, CANADA
H2X 2A1
Email: leslie@bunyip.com
Appendix A - Some Sample Queries
author=leslie and template=user
The result will consist of all records where attribute "author"
matches "leslie" with case ignored. Only USER templates will be
searched. An example of a matching attribute is "Author=Leslie L. Daigle".
This is the typical case of searching.
author=leslie and template=user:language=fr
The result will consist of the same records as above, but if
attributes are available in alternative languages, only the
ones in French will be displayed. These are either the ones which
have explicitly been tagged as having French values, or ones that
are tagged as being in the "DEF" (default) language.
schoultz and rick;search=lstring
The result will consist of all records which have one attribute value
matching "schoultz" exactly (because the default search type is exact)
and one attribute with "rick" as leading substring, both with case ignored.
One example is "Name=Rickard Schoultz".
value=phone;search=substring
The result will consist of all records which have attribute values
matching *phone*, for example the record "Name=Acme telephone inc.",
but will not match the attribute name "phone". (Since term specifier
is "value" by default, the search term could just as well have been
simply "phone").
ucdavis;search=substring and (gargano or joan):include=name,email
This search command will find records which have records containing
the words "gargano" or "joan" somewhere in the record, and has the
word "ucdavis" somewhere in a word. The result will only show the
"name" and "email" fields.
Appendix B - Some sample responses
1) FULL format responses:
# FULL USER SERVERHANDLE1 PD45
Name: Peter Deutsch
email: peterd@bunyip.com
# END
# FULL USER SERVERHANDLE1 AE1
Name: Alan Emtage
email: bajan@bunyip.com
# END
# FULL USER SERVERHANDLE1 NW1
Name: Nick West
Favourite-Bicycle-Forward-Wheel-Brand: New Bicy
+cles Acme Inc.
email: nick@bicycle.acme.com
My-favourite-song: Happy birthday to you!
-Happy birthday to you!
-Happy birthday dear Nick!
-Happy birthday to you.
# END
# FULL SERVICES SERVERHANDLE1 WWW1
Type: World Wide Web
Location: the world
# END
--------------------
2) An ABRIDGED format response:
# ABRIDGED USER SERVERHANDLE1 PD45
Peter Deutsch peterd@bunyip.com
# END
# ABRIDGED USER SERVERHANDLE1 AE1
Alan Emtage bajan@bunyip.com
# END
# ABRIDGED USER SERVERHANDLE1 WWW1
World Wide Web the world
# END
--------------------
3) HANDLE format responses:
# HANDLE USER SERVERHANDLE1 PD45
# HANDLE USER SERVERHANDLE1 AE1
# HANDLE SERVICES SERVERHANDLE1 WWW1
--------------------
4) A SUMMARY format response:
# SUMMARY SERVERHANDLE1
Matches: 35
Referrals: 2
Templates: User
-Services
-Abstracts
# END
Appendix C - Sample responses to system commands
C.1 Response to the LIST command
# FULL LIST SERVERHANDLE1
Templates: USER
-SERVICES
-HELP
# END
C.2 Response to the SHOW command
This example shows the result after issuing "show user":
# FULL USER SERVERHANDLE1
Name:
Email:
Work-Phone:
Organization-Name:
City:
Country:
# END
C.3 Response to the POLLED-BY command
# FULL POLLED-BY SERVERHANDLE1
Server-handle: serverhandle2
Cached-Host-Name: sunic.sunet.se
Cached-Host-Port: 7070
Template: USER
Field: ALL
# END
# FULL POLLED-BY SERVERHANDLE1
Server-handle: serverhandle3
Cached-Host-Name: kth.se
Cached-Host-Port: 7070
Template: ALL
Field: Name,Email
# END
C.4 Response to the POLLED-FOR command
# FULL POLLED-FOR SERVERHANDLE1
Server-Handle: serverhandle5
Template: ALL
Field: Name,Address,Job-Title,Organization-Name,
+Organization-Address,Organization-Name
# END
# FULL POLLED-FOR SERVERHANDLE1
Server-Handle: serverhandle4
Template: USER
Field: ALL
# END
C.5 Response to the VERSION command
# FULL VERSION BUNYIP.COM
Version: 2.0
Program-Name: Digger
Program-Version: 3.0b1
Program-Author: Bunyip Information Systems Inc.
Program-Author-Email: digger-info@bunyip.com
Bug-Report-Email: digger-bugs@bunyip.com
# END
C.6 Response to the CONSTRAINTS command
# FULL CONSTRAINTS SERVERHANDLE1
CONSTRAINT: maxhits
DEFAULT: 100
RANGE: 0-100
# END
# FULL CONSTRAINTS SERVERHANDLE1
CONSTRAINT: case
DEFAULT: ignore
RANGE: ignore, consider
# END
# FULL CONSTRAINTS SERVERHANDLE1
CONSTRAINT: search
DEFAULT: exact
RANGE: exact, lstring, substring, fuzzy
# END
# FULL CONSTRAINTS SERVERHANDLE1
CONSTRAINT: language
DEFAULT: DEF
RANGE: FR, EN, SV, ANY, DEF
# END
# FULL CONSTRAINTS SERVERHANDLE1
CONSTRAINT: incharset
DEFAULT: ISO-8859-1
RANGE: ISO-8859-1, UNICODE-1-1-UTF8
# END
# FULL CONSTRAINTS SERVERHANDLE1
CONSTRAINT: outcharset
DEFAULT: ISO-8859-1
RANGE: ISO-8859-1, UNICODE-1-1-UTF8, HTML
# END
C.7 Response to the COMMANDS command
# FULL COMMANDS SERVERHANDLE1
Commands: commands
-constraints
-describe
-help
-list
-polled-by
-polled-for
-show
-version
# END
Appendix D - Sample Whois++ session
Below is an example of a session between a client and a server. The
angle brackets to the left is not part of the communication, but is
just put there to denote the direction of the communication between
the server or the client. Text appended to '>' means messages from
the server and '<' from the client.
Client connects to the server
>% 220-Welcome to
>% 220-the Whois++ server
>% 220 at ACME inc.
<name=Nick:hold
>% 200 Command okay
>
># FULL USER ACME.COM NW1
> name: Nick West
> email: nick@acme.com
># END
># SERVER-TO-ASK ACME.COM
> Server-Handle: SUNETSE01
> Host-Name: whois.sunet.se
> Host-Port: 7070
># END
># SERVER-TO-ASK ACME.COM
> Server-Handle: KTHSE01
># END
>% 226 Transfer complete
<version
>% 200 Command okay
># FULL VERSION ACME.COM
> Version: 2.0
># END
>% 226 Transfer complete
>% 203 Bye
Server closes the connection
In the example above, the client connected to a Whois++ server and
queried for all records where the attribute "name" equals "Nick", and
asked the server not to close the connection after the response by
using the global constraint "HOLD".
The server responds with one record and a pointer to two other
servers that either holds records or pointers to other servers.
The client continues with asking for the servers version number
without using the HOLD constraint. After responding with protocol
version, the server closes the connection.
Note that each response from the server begins system message 200
(Command OK), and ends with system message 226 (Transfer Complete).
Appendix E - System messages
A system message begins with a '%', followed by a space and a three
digit number, a space, and an optional text message. The line message
must be no more than 81 characters long, including the terminating CR
LF pair. There is no limit to the number of system messages that may
be generated.
A multiline system message have a hyphen instead of a space in column
6, immediately after the numeric response code in all lines, except
the last one, where the space is used.
Example 1
% 200 Command okay
Example 2
% 220-Welcome to
% 220-the Whois++ server
% 220 at ACME inc.
The client is not expected to parse the text part of the response
message except when receiving reply 600 or 601, in which case the
text part is in the former case the name of a character set that
will be used by the server in the rest of the response, and in the
latter case when it specifies what language the attribute value is in.
The valid values for characters sets is specified in the "characterset"
list in the grammar in Appendix F.
The theory of reply codes is described in Appendix E in STD 10, RFC
821 [POST82].
------------------------------------------------------------------------
List of system response codes
------------------------------
110 Too many hits The number of matches exceeded
the value specified by the
maxhits constraint. Server
will still reply with as many
records as "maxhits" allows.
111 Requested constraint not supported One or more constraints in
query is not implemented, but
the search is still done.
112 Requested constraint not fulfilled One or more constraints in
query has unacceptable value
and was therefore not used,
but the search is still done.
200 Command Ok Command accepted (i.e., syntax
okay, will be executed).
The client must wait for a
transaction end system message.
201 Command Completed successfully Command accepted and executed.
203 Bye Server is closing connection
220 Service Ready Greeting message. Server is
accepting commands.
226 Transaction complete End of data. All responses to
query are sent.
430 Authentication needed Client requested information
that needs authentication.
500 Syntax error
502 Search expression too complicated This message is sent when the
server is not able to resolve
a query (i.e. when a client
sent a regular expression that
is too deeply nested).
530 Authentication failed The authentication phase
failed.
600 <token> Subsequent attribute values
are encoded in the character
set specified by <token>.
601 <token> Subsequent attribute values
are in the language specified
by <token>.
601 DEF Subsequent attribute values
are default values, i.e. they
should be used for all languages
not specified by "601 <token>"
since last "601 ANY" message.
601 ANY Subsequent attribute values
are for all languages.
Table V - System response codes
------------------------------------------------------------------------
Appendix F - The Whois++ Input Grammar
The following grammar, which uses BNF-like notation as defined in [RFC822],
defines the set of acceptable input to a Whois++ server.
N.B.: All Whois++ command, constraint, and value literals are shown here in
lower case for simplicity. These literals are to be accepted in upper, lower,
or mixed case.
whois-command = ( system-command [":" "hold"]
/ terms [":" globalcnstrnts] ) NL
system-command = "constraints"
/ "describe"
/ "commands"
/ "polled-by"
/ "polled-for"
/ "version"
/ "list"
/ "show" [1*SP string]
/ "help" [1*SP string]
/ "?" [string]
terms = and-expr *("or" and-expr)
and-expr = not-expr *("and" not-expr)
not-expr = ["not"] (term / ( "(" terms ")" ))
term = generalterm / specificterm
/ shorthandle / combinedterm
generalterm = string *(";" localcnstrnt)
specificterm = specificname "=" string
*(";" localcnstrnt)
specificname = "handle" / "value"
shorthandle = "!" string *(";" localcnstrnt)
combinedterm = attributename "=" string *(";" localcnstrnt)
globalcnstrnts = globalcnstrnt *(";" globalcnstrnt)
globalcnstrnt = localcnstrnt
/ "format" "=" format
/ "maxfull" "=" 1*digit
/ "maxhits" "=" 1*digit
/ opt-globalcnst
opt-globalcnst = "hold"
/ "authenticate" "=" auth-method
/ "name" "=" string
/ "password" "=" string
/ "language" "=" language
/ "incharset" "=" characterset
/ "ignore" "=" string
/ "include" "=" string
format = "full" / "abridged" / "handle" / "summary"
/ "server-to-ask"
language = <The language code defined in RFC1766 [ALVE95]>
characterset = "us-ascii" / "iso-8859-1" / "iso-8859-2" /
"iso-8859-3" / "iso-8859-4" / "iso-8859-5" /
"iso-8859-6" / "iso-8859-7" / "iso-8859-8" /
"iso-8859-9" / "iso-8859-10" / "UNICODE-1-1-UTF-8" /
"UNICODE-2-0-UTF-8" / charset-value
charset-value = 1*char
localcnstrnt = "search" "=" searchvalue /
"case" "=" casevalue
searchvalue = "exact" / "substring" / "regex" / "fuzzy"
/ "lstring"
casevalue = "ignore" / "consider"
auth-method = "password"
string = 0*char
attributename = 1*normalchar
char = "\" specialchar / normalchar
normalchar = <Characters 32 to 254(decimal) except specialchar>
specialchar = " " / <tab> / "=" / "," / ":" / ";" / "\" /
"*" / "." / "(" / ")" / "[" / "]" / "^" /
"$" / "!" / "?"
whitespace = 1*(" " / <tab> / <CR> / <LF> / "@")
digit = "0" / "1" / "2" / "3" / "4" /
"5" / "6" / "7" / "8" / "9"
NL = <CR LF (decimal 13 10)>
NOTE: Blanks that are significant to a query must be escaped. The
following characters, when significant to the query, may be preceded
and/or followed by a single blank:
: ; , ( ) = !
Appendix G - The Whois++ Response Grammar
The following grammar, which uses BNF-like notation as defined in [RFC822],
defines the set of responses expected from a Whois++ server upon receipt of a
valid Whois++ query.
N.B.: All the literals supplied by the Whois++ server may be in upper, lower,
or mixed case. For clarity, they are shown here in upper case only.
server = goodmessage mnl output mnl endmessage onlynl
/ badmessage onlynl endmessage onlynl
output = full / abridged / summary / handle
full = 0*(full-record / server-to-ask)
abridged = 0*(abridged-record / server-to-ask)
summary = summary-record
handle = 0*(handle-record / server-to-ask)
full-record = "# FULL " template serverhandle localhandle nl
1*(fulldata nl)
"# END" nl
abridged-record = "# ABRIDGED " template serverhandle localhandle nl
abridgeddata nl
"# END" nl
summary-record = "# SUMMARY " serverhandle nl
summarydata nl
"# END" nl
handle-record = "# HANDLE " template serverhandle localhandle nl
server-to-ask = "# SERVER-TO-ASK " serverhandle nl
server-to-askdata nl
"# END" nl
fulldata = " " attributename ": " attributevalue
abridgeddata = " " 0*( attributevalue / tab )
summarydata = " Matches: " number nl
[" Referrals: " number nl]
" Templates: " template 0*( nl "-" template)
server-to-ask-data = " Server-Handle:" <serverhandle> <nl>
" Host-Name: " hostname nl
" Host-Port: " number nl
[" Protocol: " prot nl]
0*(" " sstring ": " sstring nl)
attributename = sstring
attributevalue = longstring
template = sstring
serverhandle = sstring
localhandle = sstring
hostname = sstring
prot = sstring
longstring = string 0*( nl ( "+" / "-" ) string )
string = 0*char
sstring = 0*schar
schar = <Characters 32-254 (decimal) except special-char>
char = <Characters 32-254 (decimal) except nl>
special-char = ":" / " " / tab / nl
tab = <TAB (decimal 9)>
mnl = 1*nl
nl = onlynl [ 1*(message onlynl) ]
onlynl = <CR LF (decimal 13 10)>
message = [1*( messagestart "-" string onlynl)]
messagestart " " string onlynl
messagestart = "% " digit digit digit
goodmessage = [1*( goodmessagestart "-" string onlynl)]
goodmessagestart " " string onlynl
goodmessagestart= "% 200"
messagestart = "% " digit digit digit
badmessage = [1*( badmessagestart "-" string onlynl)]
badmessagestart " " string onlynl
badmessagestart = "% 5" digit digit
endmessage = endmessageclose / endmessagecont
endmessageclose = [endmessagestart " " string onlynl]
byemessage
endmessagecont = endmessagestart " " string onlynl
endmessagestart = "% 226"
byemessage = byemessagestart " " string onlynl
endmessagestart = "% 203"
number = 1*( digit )
digit = "0" / "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9"
Appendix H - Description of Regular expressions
The regular expressions described in this section are the same as used
in many other applications and operating systems. However, it is very
simple and does not include logical operators AND and OR.
Searches using regular expressions always use substring
matching except when the regular expression contains the characters
'^' or '$'.
Character Function
--------- --------
<any except those listed in this table> Matches itself
. Matches any character
a* Matches zero or more 'a'
[ab] Matches 'a' or 'b'
[a-c] Matches 'a', 'b' or 'c'
^ Matches beginning of
a token
$ Matches end of a token
Examples
---------
String Matches Doesn't match
------- ------- -------------
hello xhelloy heello
h.llo hello helio
h.*o hello helloa
h[a-f]llo hello hgllo
^he.* hello ehello
.*lo$ hello helloo