12 May
2005
12 May
'05
7:20 p.m.
Dave Robillard wrote:
On Thu, 2005-12-05 at 17:54 +0200, stefan kersten
wrote:
I use this sort of code for request/response RPC-like IPC. In order for
this to work I did have to fix a bug in liblo-0.18, but that was about
sockets not being closed properly. I wonder if this fix would solve your
problem too. I sent the bugfix to Steve, but at that moment he'd just
released 0.18 and feared the anger of Frenando@planetccrma if he'd
release a 0.19. So I guess it's queued for the next release. In the
meantime there is a patched version up at:
http://prdownloads.sourceforge.net/freebob/liblo-0.18-pp.tar.bz2?download
Maybe you should try this one and see if it solves the problem.
As a side note: It might be worthwile to think about a generic solution
to this need for inter-process notifications and/or RPC. I see
LinuxSampler implementing a solution, I know we at freebob need it,
apparently Om does also, the question comes up regarding aeolus. I would
think that this is a natural extention because it pops up every time one
wants to control an app with multiple controllers (e.g. a separate UI
and a HW controller).
Greets,
Pieter
PS:For your reference: I added my code below. It is from the IPC handler
in the freebob deamon, but I removed all error checking and debug
statements for clarity.
<code>
int request_handler(const char *path, const char *types, lo_arg **argv,
int argc, lo_message msg, void *user_data) {
IPCHandler *handler=(IPCHandler *)user_data;
return handler->requestHandler(path, types,argv, argc, msg);
}
int
IPCHandler::requestHandler(const char *path,
const char *types,
lo_arg **argv,
int argc,
lo_message msg)
{
lo_address src=lo_message_get_source ( msg );
if(argc==1) {
if(strcasecmp(&argv[0]->s,"connection_info")==0) {
// send response
lo_send(src, "/response", "s", pConnectionInfo );
}
}
return 0;
}
FBReturnCodes IPCHandler::initialize()
{
/* start a new server */
m_serverThread = lo_server_thread_new(portnumber, ipc_error);
/* add request handler */
lo_server_thread_add_method(m_serverThread, "/freebob/request",
"s",
request_handler, (void *)this);
return eFBRC_Success;
}
FBReturnCodes IPCHandler::start() {
lo_server_thread_start(m_serverThread);
return eFBRC_Success;
}
FBReturnCodes IPCHandler::stop() {
lo_server_thread_stop(m_serverThread);
return eFBRC_Success;
}
</code>
On Thu, May 12, 2005 at 05:22:43PM +0200, Alfons
Adriaensen wrote:
I allow either method in Om. Using the client address does work
usually, but there seems to be a bug in liblo (or below) where the
source network address is garbled, that I havn't been able to figure out
yet... allowing the user to explicitly set the address allows working
around this and other networking oddities.
One thing I forgot to mention regarding /addclient
: the response
to this will include a client ID (integer) that is a required
parameter to all polled requests for information, such as e.g.
the list of stops. This ID identifies the client on the common
server socket (I see no other way to do this with a single socket).
i might be missing something, but why don't you use the
client network address as a unique identifier? you can use
recvfrom(2) to extract the return address from a udp packet.