How Do You Activate Sparkle's XPC Services?

Jun 22nd, 2019

The Sparkle XPC fork is even better than I would’ve imagined!

As I mentioned in the previous post about Sparkle’s XPC branch, you can switch to the new framework version and the new types without having to change much else. The new API is very similar to the old one. If you switch to the work-in-progress ui-separation-and-xpc branch, then you can continue to use CocoaPods or Carthage if all you want is the new API.

Only when you want to use the XPC services will you have to build the Sparkle build products yourself.

That means the Sparkle framework does not require the XPC services to work. They are optional. Unless you want to use them, you won’t notice any difference.

Huh.

But how do you set up your app to use the XPC services if you want to? Is there a new initializer or delegate callback or anything? If disabling XPC services is not required, then enabling must be, right?

Turns out Sparkle does all the decision making for us. In the Sparkle.xcodeproj, search for occurrences of the SPUXPCServiceExists function. Then you’ll see where Sparkle checks if an XPC service is present in its host bundle, aka your app:

If no XPC services are bundled with your app, Sparkle more or less behaves like it used to for a decade and more.
If you bundle the XPC services with your app, Sparkle will utilize them instead.

This is great, because that means you have zero configuration to do!

I was puzzled for a while after I set up the basics yesterday. What’s the next step? Bundle the XPC services with the app, and then what? Nothing: There is no step three!

I’m happy to see that the Sparkle project was designed to be this simple to use.

The SPUXPCServiceExists function is also pretty simple: see code for SPUXPCServiceInfo.m on GitHub.

This was the second post in a series:

How to migrate to the new Sparkle XPC branch
How to toggle use of XPC service (this post)
How to build, embed, and notarize the XPC services in your app

Links to this article

Backlinks Added to the Blog

Everytime I mention, think of, and link to Andy Matuschak’s public notes, I really like how each note displays a list of backlinks at the bottom. In my note-taking, I don’t want backlinks to be added automatically into the content. I can get by with other means just fine to figure out what links to the current note.
How to Migrate to the New Sparkle Updater XPC Branch

This is the first post in a series: The standard solution to provide app updates outside the Mac App Store is to use the amazing Sparkle framework. The releases of Sparkle don’t support sandboxed applications well, though, so the core maintainer Kornel Lesiński (@kornelski) is working on a more secure fork of Sparkle next to the existing one. He’s maintaining the regular Sparkle, and the fork. The fork features various XPC services to deal with Gatekeeper security configurations and Sandbox entitlements in a proper way. (I have to phrase it in such a vague way because I have no clue about the details, yet. Explanations are very welcome in the comments!)
Reference Xcode Configuration Variables in Objective-C

When I pointed out that Sparkle finds its XPC services on its own, I mentioned you can see how it does this by searching for “SPUXPCServiceExists”. If you take a look at the use of this function, you’ll see something like this in the Objective-C (!) source files:
Xcode Project Setup to Build, Embed, Codesign, Notarize, and Use the Sparkle XPC Services

In the previous post, I talked about how to download the “modern” Sparkle updater branch called ui-separation-and-xpc that allows you to update sandboxed apps and migrate your code to use the new types. This time, we’re going to use the actual XPC services that do the grunt work.