Connecting iPadOS and visionOS apps over the local network

At a glance

Project structure

Source bundle/
└── iPadCompanionApp/
    ├── Companion/
    │   ├── CompanionApp.swift
    │   └── Views/
    │       ├── ControlPanelView.swift
    │       ├── RobotAndControlsView.swift
    │       └── ServerContentView.swift
    ├── RobotConfigurationExperience/
    │   ├── RobotConfigurationExperienceApp.swift
    │   └── Views/
    │       └── ClientContentView.swift
    ├── SharedContent/
    │   └── Models/
    │       ├── NetworkCommand.swift
    │       └── RobotViewModel.swift
    └── Packages/
        └── PeerToPeerMessaging/
            └── Sources/
                └── PeerToPeerMessaging/
                    ├── ConnectionTypes.swift
                    ├── Actors/
                    │   └── Client.swift
                    ├── TLS/
                    │   └── CertificateTrustManager.swift
                    └── PeerMessagingController.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 5 project/configuration file(s) and 26 source declaration(s).

Overall architecture

flowchart LR
    N1["CompanionApp"]
    N2["ServerContentView"]
    N3["RobotViewModel"]
    N4["Client"]
    N5["SwiftUI / PeerToPeerMessaging APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4
    N4 --> N5

Reference code

iPadCompanionApp/Companion/CompanionApp.swift:11 — architecture anchor

@main
struct CompanionApp: App {
    @State private var serverController: PeerMessagingController<Server<NetworkCommand>>
    @State private var robotViewModel: RobotViewModel

    init() {
        let serverController = PeerMessagingController<Server<NetworkCommand>>()
        let robotViewModel = RobotViewModel(serverController)

        self.serverController = serverController
        self.robotViewModel = robotViewModel
    }

    var body: some Scene {
        WindowGroup {
            ServerContentView()
                .environment(serverController)
                .environment(robotViewModel)
                .ignoresSafeArea()
        }
    }
}

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into visionOS.

Ownership and state

classDiagram
    CompanionApp *-- PeerMessagingController : serverController
    CompanionApp *-- RobotViewModel : robotViewModel
    RobotConfigurationExperienceApp *-- PeerMessagingController : clientController
    RobotConfigurationExperienceApp *-- RobotViewModel : robotViewModel

Ownership evidence

iPadCompanionApp/Companion/CompanionApp.swift:13 — stored dependency or nearest verified ownership anchor

@main
struct CompanionApp: App {
    @State private var serverController: PeerMessagingController<Server<NetworkCommand>>
    // ...
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Concurrency, scheduling, and thread safety

Evidence limit: actor isolation, async/await, or Task creation does not by itself prove background-thread execution; Sendable conformance alone does not prove thread-safe mutation.

@MainActor/MainActor.run, DispatchQueue.main, and RunLoop.main are reported as distinct isolation, queue, and event-loop mechanisms. A plain Task is kept separate from Task.detached; neither is labeled as a background thread.

Reference code

iPadCompanionApp/Companion/Views/RobotAndControlsView.swift:45 — representative execution boundary

    private func handleRobotEvents() async {
        for await case .robotEvent(let event) in serverController.incomingMessages {
            robotViewModel.handleRobotEvent(event)
        }
    }

State propagation, frameworks, and dependencies

Evidence limit: an import proves a source-level compilation dependency at the cited line; it does not prove runtime use, architectural adoption, or whether a Swift package is a direct application dependency.

receive(on:) describes downstream delivery scheduling, while subscribe(on:) describes upstream subscription/request/cancel scheduling. An import Combine alone establishes neither behavior nor a Store, reducer, Redux, or other application architecture.

Class and protocol design

iPadCompanionApp/Packages/PeerToPeerMessaging/Sources/PeerToPeerMessaging/Protocols/PeerMessagingProtocols.swift:17 — representative type boundary

public protocol PeerMessagingManager<Message>: Actor where Message: PeerToPeerMessage {
    associatedtype Message: PeerToPeerMessage
    // ...
}

The source explicitly defines local protocol relationships: NetworkCommand → PeerToPeerMessage, RobotEvent → PeerToPeerMessage, MockNetworkActor → PeerMessagingManager.

Access control

Reference code

iPadCompanionApp/Companion/CompanionApp.swift:13 — representative boundary

@main
struct CompanionApp: App {
    @State private var serverController: PeerMessagingController<Server<NetworkCommand>>
    // ...
}

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Naming conventions

• Types: App: CompanionApp, RobotConfigurationExperienceApp; Client: Client; Command: NetworkCommand; Manager: CertificateTrustManager, PeerMessagingManager; View: ClientContentView, ControlPanelView, RobotAndControlsView, RobotView, RobotWindowView; ViewModel: RobotViewModel.
• Protocols: PeerMessagingManager, PeerToPeerMessage.
• Methods: toggleWindowPresentation, syncNewSelectedColor, toggleVolumeVisibility, reset, load, loadEntityFromRCPro, updateRobotAppearance, handleRobotEvent.
• Files: iPadCompanionApp/Companion/CompanionApp.swift, iPadCompanionApp/RobotConfigurationExperience/RobotConfigurationExperienceApp.swift, iPadCompanionApp/SharedContent/Models/NetworkCommand.swift, iPadCompanionApp/SharedContent/Models/RobotViewModel.swift, iPadCompanionApp/Packages/PeerToPeerMessaging/Sources/PeerToPeerMessaging/Actors/Client.swift, iPadCompanionApp/Packages/PeerToPeerMessaging/Sources/PeerToPeerMessaging/TLS/CertificateTrustManager.swift.

Architecture takeaways

• CompanionApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, PeerToPeerMessaging, Network, RealityKit through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• Local protocol relationships provide an explicit substitution boundary.

Source map

• Official Apple documentation