multiplexer(n)					      One-to-many communication with sockets.					    multiplexer(n)

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NAME

       multiplexer - One-to-many communication with sockets.

SYNOPSIS

       package require Tcl  8.2

       package require logger

       package require multiplexer  ?0.2?

       ::multiplexer::create

       ${multiplexer_instance}::Init port

       ${multiplexer_instance}::Config key value

       ${multiplexer_instance}::AddFilter cmdprefix

       cmdprefix data chan clientaddress clientport

       ${multiplexer_instance}::AddAccessFilter cmdprefix

       cmdprefix chan clientaddress clientport

       ${multiplexer_instance}::AddExitFilter cmdprefix

       cmdprefix chan clientaddress clientport

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DESCRIPTION

       The  multiplexer  package  provides  a generic system for one-to-many communication utilizing sockets.  For example, think of a chat system
       where one user sends a message which is then broadcast to all the other connected users.

       It is possible to have different multiplexers running concurrently.

       ::multiplexer::create
	      The create command creates a new multiplexer 'instance'.	For example:
	      set mp [::multiplexer::create]
	      This instance can then be manipulated like so:
	      ${mp}::Init 35100

       ${multiplexer_instance}::Init port
	      This starts the multiplexer listening on the specified port.

       ${multiplexer_instance}::Config key value
	      Use Config to configure the multiplexer instance.  Configuration options currently include:

	      sendtoorigin
		     A boolean flag. If true, the sender will receive a copy of the sent message.  Defaults to false.

	      debuglevel
		     Sets the debug level to use for the multiplexer instance, according to those specified by the logger  package  (debug,  info,
		     notice, warn, error, critical).

       ${multiplexer_instance}::AddFilter cmdprefix
	      Command to add a filter for data that passes through the multiplexer instance.  The registered cmdprefix is called when data arrives
	      at a multiplexer instance. If there is more than one filter command registered at the instance they will be called in the  order	of
	      registristation,	and  each  filter  will get the result of the preceding filter as its argument. The first filter gets the incoming
	      data as its argument. The result returned by the last filter is the data which will be broadcast to all clients of  the  multiplexer
	      instance.  The command prefix is called as

	      cmdprefix data chan clientaddress clientport
		     Takes  the incoming data, modifies it, and returns that as its result. The last three arguments contain information about the
		     client which sent the data to filter: The channel connecting us to the client, its ip-address, and its ip-port.

       ${multiplexer_instance}::AddAccessFilter cmdprefix
	      Command to add an access filter.	The registered cmdprefix is called when a new client socket  tries  to	connect  to  the  multixer
	      instance.  If there is more than one access filter command registered at the instance they will be called in the order of registris-
	      tation. If any of the called commands returns -1 the access to the multiplexer instance is denied and the client channel	is  closed
	      immediately. Any other result grants the client access to the multiplexer instance.  The command prefix is called as

	      cmdprefix chan clientaddress clientport
		     The arguments contain information about the client which tries to connected to the instance: The channel connecting us to the
		     client, its ip-address, and its ip-port.

       ${multiplexer_instance}::AddExitFilter cmdprefix
	      Adds filter to be run when client socket generates an EOF condition.  The registered cmdprefix is called when a client socket of the
	      multixer	signals  EOF. If there is more than one exit filter command registered at the instance they will be called in the order of
	      registristation. Errors thrown by an exit filter are ignored, but logged. Any result returned by an exit	filter	is  ignored.   The
	      command prefix is called as

	      cmdprefix chan clientaddress clientport
		     The  arguments  contain information about the client which signaled the EOF: The channel connecting us to the client, its ip-
		     address, and its ip-port.

BUGS, IDEAS, FEEDBACK
       This document, and the package it describes, will undoubtedly contain bugs and other problems.  Please report such in the  category  multi-
       plexer  of  the Tcllib SF Trackers [http://sourceforge.net/tracker/?group_id=12883].  Please also report any ideas for enhancements you may
       have for either package and/or documentation.

KEYWORDS

       chat, multiplexer

CATEGORY

       Programming tools

multiplexer								0.2							    multiplexer(n)