I am developing an application on MAC OS . It has 2 parts -- a UI element and a daemon (which needs to run continuously and must restart on being killed). Currently I am using launchctl to restart the daemon.
But there is another issue. I need the 2 parts of my application to communicate with each other . For this I am using distibuted objects for the same (as given here) . However this does not work when I launch the daemon with launchctl. Can anyone suggest some alternative???
I use NSDistributedNotifications to handle this pretty well in one app, even on 10.7. You have to do your own handshaking since this can be lossy (i.e. include an ack notification and resend in case of timeouts). A side effect of this approach is that if there are multiple clients running (particularly under fast user switching), all of them receive the notifications. That's good in the particular case of this app. It's also extremely simple to implement.
For another app, I use two FIFOs. The server writes to one and reads from the other. The client does the opposite. You can of course also use a network socket to achieve the same thing. I tend to prefer FIFOs because you don't have to do deal with locking down a network socket.
That said, what problem are you seeing using distributed objects under launchd? Are you just seeing problems on 10.7 (which changed the rules around the launchd context)?
Are you using launchd to lazy-load the daemon when the port is accessed (this is the normal way to do it). Have you considered using a launchagent instead of a launchdaemon?
EDIT:
Ah... the bootstrap server. Yes. You need to execute things in the correct bootstrap context in order to talk to them. The bootstrap context for the login session is rooted to the windowserver process. LaunchDaemons run in a different context, so they can't directly communicate with the login sessions. Some background reading:
I am not aware of anyway to get processes into the correct context without using launchctl bsexec. Launchd technically has an API (launchctl uses it), but it is not well documented. You can pull the source from opensource.apple.com.
Even if you stay with NSDistributedObject, I would try to use something other than the bootstrap service if you can. As I mentioned, I tend to use other tools and avoid NSDistributedObject. In my opinion, for the same reasons that REST is better than SOAP, simple protocols are usually better than remote objects. (YMMV)