Two-way communication with the Swift binary

[sindresorhus]

We'll need two-way communication to be able to implement pause/resume recording (#28) and to fix #40. We need to use some kind of socket/IPC communication (wulkano/Aperture#8 (comment)).

[sindresorhus]

I just thought of a possible solution. We could use NSDistributedNotificationCenter to communicate between processes.

So on the Swift side we would send a notification when the Swift binary actually started recording:

DistributedNotificationCenter.default().postNotificationName(NSNotification.Name("aperture.recording"), object: nil, userInfo: ["file": url], deliverImmediately: true)

And on the Electron-side we would listen for that event:

electron.systemPreferences.subscribeNotification('aperture.recording', (event, userInfo) => {
	console.log('event', event, userInfo);
});

Which would output the following from Electron:

event aperture.recording { file: '…' }

This would work both ways. The downside is that we would need to write it specifically for Electron, so it would need to be a different mode/option in Aperture.

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Additional reading: https://academy.realm.io/posts/thomas-goyne-fast-inter-process-communication/

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@albinekb @LarsJK Thoughts?

[LarsJK]

Yeah seems like a good solution to me, although I'm not too familiar with DistributedNotificationCenter or Electron..
Maybe you could use libnotify like that last article mentions as a C alternative to DistibutedNotificationCenter? Seems like there are a few node packages for libnotify..

[sindresorhus]

@LarsJK Ah yeah, that's an interesting idea. I couldn't find a Node.js module for this, but shouldn't be too hard to create a simple one that interfaces libnotify using FFI.

[LarsJK]

Maybe XPC could be an alternative as well..

Haven't actually used any of these myself, so I don't know which one would be best..

[albinekb]

Perhaps that lib could use the electron implementation if it's available (and thus we could release a v0 that only supports the electron implementation now)? 🤔 @sindresorhus But yes, that sounds like the best solution so far.