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Net::Server::Multiplex(3)




NAME

       Net::Server::Multiplex - Multiplex several connections within one
       process


SYNOPSIS

         package MyPlexer;

         use base 'Net::Server::Multiplex';

         sub mux_input {
            #...code...
         }

         __PACKAGE__->run();


DESCRIPTION

       This personality is designed to handle multiple connections all within
       one process.  It should only be used with protocols that are guaranteed
       to be able to respond quickly on a packet by packet basis.  If
       determining a response could take a while or an unknown period of time,
       all other connections established will block until the response
       completes.  If this condition might ever occur, this personality should
       probably not be used.

       This takes some nice features of Net::Server (like the server listen
       socket setup, configuration file processing, safe signal handling,
       convenient inet style STDIN/STDOUT handling, logging features,
       deamonization and pid tracking, and restartability -SIGHUP) and some
       nice features of IO::Multiplex (automatic buffered IO and per-file-
       handle objects) and combines them for an easy-to-use interace.

       See examples/samplechat.pl distributed with Net::Server for a simple
       chat server that uses several of these features.


PROCESS FLOW

       The process flow is written in an open, easy to override, easy to hook,
       fashion.  The basic flow is shown below.

         $self->configure_hook;

         $self->configure(@_);

         $self->post_configure;

         $self->post_configure_hook;

         $self->pre_bind;

         $self->bind;

         if( Restarting server ){
            $self->restart_open_hook();
         }

         $self->post_bind_hook;

         $self->post_bind;

         $self->pre_loop_hook;

         $self->loop; # This basically just runs IO::Multiplex::loop
         # For routines inside a $self->loop
         # See CLIENT PROCESSING below

         $self->pre_server_close_hook;

         $self->post_child_cleanup_hook;

         $self->server_close;

         if( Restarting server ){
            $self->restart_close_hook();
            $self->hup_server;
            # Redo process again starting with configure_hook
         }

       The server then exits.


CLIENT PROCESSING

       The following represents the client processing program flow:

         $self->{server}->{client} = Net::Server::Proto::TCP->accept();  # NOTE: Multiplexed with mux_input() below

         if (check_for_dequeue seconds have passed) {
           $self->run_dequeue();
         }

         $self->get_client_info;

         $self->post_accept_hook; # Net::Server style

         if( $self->allow_deny

             && $self->allow_deny_hook ){

           # (Net::Server style $self->process_request() is never called.)

           # A unique client specific object is created
           # for all mux_* methods from this point on.
           $self = __PACKAGE__->new($self, client);

           $self->mux_connection; # IO::Multiplex style

           for (every packet received) {
             $self->mux_input;  # NOTE: Multiplexed with accept() above
           }

         }else{

           $self->request_denied_hook;

           # Notice that if either allow_deny or allow_deny_hook fails, then
           # new(), mux_connection(), and mux_input() will never be called.
           # mux_eof() and mux_close() will still be called, but using a
           # common listen socket callback object instead of a unique client
           # specific object.

         }

         $self->mux_eof;

         $self->post_process_request_hook;

         $self->mux_close;

       This process then loops multiplexing between the accept() for the next
       connection and mux_input() when input arrives to avoid blocking either
       one.


HOOKS

       The *_hook methods mentioned above are meant to be overridden with your
       own subroutines if you desire to provide additional functionality.

       The loop() method of Net::Server has been overridden to run the loop
       routine of IO::Multiplex instead.  The Net::Server methods may access
       the IO::Multiplex object at "$self->{mux}" if desired.  The
       IO::Multiplex methods may access the Net::Server object at
       "$self->{net_server}" if desired.

       The process_request() method is never used with this personality.

       The other Net::Server hooks and methods should work the same.

       "$self->run_dequeue()"
           This hook only gets called in conjuction with the check_for_dequeue
           setting.  It will run every check_for_dequeue seconds.  Since no
           forking is done, this hook should run fast in order to prevent
           blocking the rest of the processing.


TIMEOUTS

       set_timeout

       To utilize the optional timeout feature of IO::Multiplex, you need to
       specify a timeout by using the set_timeout method.

       $self->{net_server}->{mux}->set_timeout($fh, $seconds_from_now);

       $fh may be either a client socket or a listen socket file descriptor
       within the mux.  $seconds_from_now may be fractional to achieve more
       precise timeouts.  This is used in conjuction with mux_timeout, which
       you should define yourself.

       mux_timeout

       The main loop() routine will call $obj->mux_timeout($mux, $fh) when the
       timeout specified in set_timeout is reached where $fh is the same as
       the one specified in set_timeout() and $obj is its corresponding object
       (either the unique client specific object or the main listen callback
       object) and $mux is the main IO::Multiplex object itself.


CALLBACK INTERFACE

       Callback objects should support the following interface.  You do not
       have to provide all of these methods, just provide the ones you are
       interested in.  These are just like the IO::Multiplex hooks except that
       STDOUT is tied to the corresponding client socket handle for your
       convenience and to more closely emulate the Net::Server model.
       However, unlike some other Net::Server personalities, you should never
       read directly from STDIN yourself.   You should define one or more of
       the following methods:

       mux_connection ($mux,$fh)

       (OPTIONAL) Run once when the client first connects if the allow_deny
       passes.  Note that the "$self->{net_server}->{server}" property hash
       may be modified by future connections through Net::Server.  Any values
       within it that this object may need to use later should be copied
       within its own object at this point.

       Example:
         $self->{peerport} = $self->{net_server}->{server}->{peerport};

       mux_input ($mux,$fh,\$data)

       (REQUIRED) Run each time a packet is read.  It should consume $data
       starting at the left and leave unconsumed data in the scalar for future
       calls to mux_input.

       mux_eof ($mux,$fh,\$data)

       (OPTIONAL) Run once when the client is done writing.  It should consume
       the rest of $data since mux_input() will never be run again.

       mux_close ($mux,$fh)

       (OPTIONAL) Run after the entire client socket has been closed.  No more
       attempts should be made to read or write to the client or to STDOUT.

       mux_timeout ($mux,$fh)

       (OPTIONAL) Run once when the set_timeout setting expires as explained
       above.


BUGS

       This is only known to work with TCP servers.

       If you need to use the IO::Multiplex style set_timeout / mux_timeout
       interface, you cannot use the Net::Server style check_for_dequeue /
       run_dequeue interface.  It will not work if the check_for_dequeue
       option is specified.  The run_dequeue method is just a compatibility
       interface to comply with the Net::Server::Fork style run_dequeue but is
       implemented in terms of the IO::Multiplex style set_timeout and
       mux_timeout methods.


AUTHOR

       Rob Brown <bbb@cpan.org>


MAINTAINER

       Paul Seamons <paul@seamons.com>


LICENSE

         This package may be distributed under the terms of either the
         GNU General Public License
            or the
         Perl Artistic License

         All rights reserved.


SEE ALSO

       Net::Server(3) by Paul Seamons <paul@seamons.com>,

       IO::Multiplex(3) by Bruce Keeler <bruce@gridpoint.com>.



perl v5.10.0                      2007-02-02         Net::Server::Multiplex(3)

Mac OS X 10.6 - Generated Thu Sep 17 20:14:18 CDT 2009
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