macOS Inter Process Communication

I don't think that would work even if you used a distributed notification centre. The senario were a distributed notification centre works is where the daemon process wants to send out notifications to clients, not vice-versa.

You might want to look at the documentation under Interapplication Communication. Perhaps start with Getting Started with Interapplication Communication.

I don't think Pasteboards are what you want either. These are used user initiated copy'n'paste like operations.

Note that what windows calls a service is nothing like what Mac OS X calls a Service. Under Mac OS X, and Unix in general, you want to be using and looking for the term daemon.

It sounds like you want to do remote messaging. Try Distributed Objects.

But perhaps this is overkills. Perhaps you could just use a file system socket.

Depending on what you want to do, you could implement a service, as would appear in the Services submenu of the application menu as described in this Doc. Such a service can be invoked either by the user, from the menu, or by the program itself (read the section). If you do not want the service to be directly accessible to the user, this might not be the strategy you want to employ.

Alternately, you could implement and publish a Bonjour service. These, IIRC, communicate through pipes (NSPipe — pipes are one-way, so you would need two for back and forth communication) and you could just create a unique type of service that might be application-specific. Bonjour services are node-agnostic: they can live on any machine on the network and be accessed from any machine on the network. If security might be a concern, you would have to set up the service provider to check that the client is ok (e.g., not requesting information or action that should be prohibited to it).

sivaprakash said:

Can you please give me some tutorial which explains step-by-step procedures to write and register service also pass data from client application?

Thanks
Siva

Click to expand...

You should be able to search for any System V IPC Tutorial out on the web.

A quick search came up with this site:

http://www.academictutorials.com/ipc/ipc-system-v-ipc.asp

IPC is pretty standard across the *nix variants.

Depending on what you need to do, one possibility would be to use a NSDistantObject. This would allow you to communicate directly between two applications by passing messages to an object. What that would involve is:

- Create a class that both server app and client(s) are aware of (this might involve building a framework for the class)

- Write a server app that "vends" the object to make it available to the client app

- The client app will look for the vended object and establish a proxy object that it can use to communicate directly via Objective-C method invocations (NSInvocation). Methods can be synchronous (blocking the sending thread) or not. The distant object can also return values to the sender (if the invocation is synchronous).

This is pretty elaborate, but mostly a lot of busywork to implement. You could just use the vended object as a means for the client to locate the server daemon and obtain a pair of pipes – not really sure, but I suspect passing methods to distant objects is probably not terribly efficient and should be used sparingly.

Distant Objects Documentation

If you need bi-directional messaging, it's so much easier to create a socket and communicate that way. Then it won't matter if your clients are on the same node or not.

If you want to get fancy, communicate through shared memory.

Here's a little powerpoint tutorial from University of Chicago

The site I posted above has plenty of IPC tutorials for you to look at and try.