Event::RPC(3) User Contributed Perl Documentation Event::RPC(3)NAMEEvent::RPC - Event based transparent Client/Server RPC framework
SYNOPSIS
#-- Server Code
use Event::RPC::Server;
use My::TestModule;
my $server = Event::RPC::Server->new (
port => 5555,
classes => { "My::TestModule" => { ... } },
);
$server->start;
----------------------------------------------------------
#-- Client Code
use Event::RPC::Client;
my $client = Event::RPC::Client->new (
server => "localhost",
port => 5555,
);
$client->connect;
#-- Call methods of My::TestModule on the server
my $obj = My::TestModule->new ( foo => "bar" );
my $foo = $obj->get_foo;
ABSTRACTEvent::RPC supports you in developing Event based networking
client/server applications with transparent object/method access from
the client to the server. Network communication is optionally encrypted
using IO::Socket::SSL. Several event loop managers are supported due to
an extensible API. Currently Event and Glib are implemented.
DESCRIPTIONEvent::RPC consists of a server and a client library. The server
exports a list of classes and methods, which are allowed to be called
over the network. More specific it acts as a proxy for objects created
on the server side (on demand of the connected clients) which handles
client side methods calls with transport of method arguments and return
values.
The object proxy handles refcounting and destruction of objects created
by clients properly. Objects as method parameters and return values are
handled as well (although with some limitations, see below).
For the client the whole thing is totally transparent - once connected
to the server it doesn't know whether it calls methods on local or
remote objects.
Also the methods on the server newer know whether they are called
locally or from a connected client. Your application logic is not
affected by Event::RPC at all, at least if it has a rudimentary clean
OO design.
For details on implementing servers and clients please refer to the man
pages of Event::RPC::Server and Event::RPC::Client.
REQUIREMENTSEvent::RPC needs either one of the following modules on the server
(they're not necessary on the client):
Event
Glib
They're needed for event handling resp. mainloop implementation. If
you like to use SSL encryption you need to install
IO::Socket::SSL
As well Event::RPC makes heavy use of the
Storable
module, which is part of the Perl standard library. It's important that
both client and server use exactly the same version of the Storable
module! Otherwise Event::RPC client/server communication will fail
badly.
INSTALLATION
You get the latest installation tarballs and online documentation at
this location:
http://www.exit1.org/Event-RPC/
If your system meets the requirements mentioned above, installation is
just:
perl Makefile.PL
make test
make install
EXAMPLES
The tarball includes an examples/ directory which contains two
programs:
server.pl
client.pl
Just execute them with --help to get the usage. They do some very
simple communication but are good to test your setup, in particular in
a mixed environment.
LIMITATIONS
Although the classes and objects on the server are accessed
transparently by the client there are some limitations should be aware
of. With a clean object oriented design these should be no problem in
real applications:
Direct object data manipulation is forbidden
All objects reside on the server and they keep there! The client just
has specially wrapped proxy objects, which trigger the necessary magic
to access the object's methods on the server. Complete objects are
never transferred from the server to the client, so something like this
does not work:
$object->{data} = "changed data";
(assuming $object is a hash ref on the server).
Only method calls are transferred to the server, so even for "simple"
data manipulation a method call is necessary:
$object->set_data ("changed data");
As well for reading an object attribute. Accessing a hash key will
fail:
my $data = $object->{data};
Instead call a method which returns the 'data' member:
my $data = $object->get_data;
Methods may exchange objects, but not in a too complex structure
Event::RPC handles methods which return objects. The only requirement
is that they are declared as a Object returner on the server (refer to
Event::RPC::Server for details), but not if the object is hided inside
a deep complex data structure.
An array or hash ref of objects is Ok, but not more. This would require
to much expensive runtime data inspection.
Object receiving parameters are more restrictive, since even hiding
them inside one array or hash ref is not allowed. They must be passed
as a direkt argument of the method subroutine.
AUTHORS
JA~Xrn Reder <joern at zyn dot de>
COPYRIGHT AND LICENSE
Copyright (C) 2002-2006 by Joern Reder, All Rights Reserved.
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.14.1 2008-10-25 Event::RPC(3)
