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ActiveTcl User Guide
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multiplexer(n) 0.2 "One-to-many communication with
sockets."
multiplexer - One-to-many communication with sockets.
package require Tcl
package require logger
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:
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set mp [::multiplexer::create]
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This instance can then be manipulated like so:
- ${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 registristation. 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.
chat , multiplexer