nns_protocol man page

nameserv::protocol — Name service facility, client/server protocol

Synopsis

Bind name data

Release

Search pattern

ProtocolVersion

ProtocolFeatures

Search/Continuous/Start tag pattern

Search/Continuous/Stop tag

Search/Continuous/Change tag add|remove response

Description

The packages nameserv::server, nameserv, and nameserv::common provide a simple unprotected name service facility for use in small trusted environments.

Please read Name service facility, introduction first.

This document contains the specification of the network protocol which is used by client and server to talk to each other, enabling implementations of the same protocol in other languages.

Nano Name Service Protocol Version 1

This protocol defines the basic set of messages to be supported by a name service, also called the Core feature.

Basic Layer

The basic communication between client and server is done using the remote-execution protocol specified by the Tcl package comm. The relevant document specifying its on-the-wire protocol can be found in comm_wire.

All the scripts exchanged via this protocol are single commands in list form and thus can be interpreted as plain messages instead of as Tcl commands. The commands/messages specified in the next section are the only commands understood by the server-side. Command and variable substitutions are not allowed within the messages, i.e. arguments have to be literal values.

The protocol is synchronous. I.e. for each message sent a response is expected, and has to be generated. All messages are sent by the client. The server does not sent messages, only responses to messages.

Message Layer

Bind name data
The client sends this message when it registers itself at the service with a name and some associated data. The server has to send an error response if the name is already in use. Otherwise the response has to be an empty string.

The server has to accept multiple names for the same client.
Release
The client sends this message to unregister all names it is known under at the service. The response has to be an empty string, always.
Search pattern
The client sends this message to search the service for names matching the glob-pattern. The response has to be a dictionary containing the matching names as keys, and mapping them to the data associated with it at Bind-time.
ProtocolVersion
The client sends this message to query the service for the highest version of the name service protocol it supports. The response has to be a positive integer number.

Servers supporting only Nano Name Service Protocol Version 1 have to return 1.
ProtocolFeatures
The client sends this message to query the service for the features of the name service protocol it supports. The response has to be a list containing feature names.

Servers supporting only Nano Name Service Protocol Version 1 have to return {Core}.

Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category nameserv of the Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist]. Please also report any ideas for enhancements you may have for either package and/or documentation.

See Also

comm_wire(n), nameserv(n), nameserv::server(n)

Keywords

comm, name service, protocol

Category

Networking

Info

0.1 tcllib Name service facility