DJI Control Server — iOS

iOS app that exposes a high-level REST API to control DJI drones and fetch certain state variables. Primarily created to control DJI drones from code in a GPS-denied indoor environment.

This is an iOS port of dkapur17/DJIControlServer (originally an Android/Kotlin app). The REST API is byte-for-byte compatible with the original, so existing clients — including the Python DJIControlClient — work unchanged. The drone connects to an Apple device running this app, and the control server becomes available on the device's IP address on port 8080.

What changed in the port

Concern	Android (original)	iOS (this fork)
Language	Kotlin	Swift 5.5
UI	Android Views (activity_main.xml)	SwiftUI
Drone SDK	DJI Mobile SDK for Android 4.16.1	DJI Mobile SDK for iOS ~> 4.16
HTTP server	Ktor + Netty	Embedded server on Apple's Network framework
JSON	Gson	Codable / JSONEncoder
Async	Kotlin coroutines (suspendCoroutine)	Swift concurrency (async/await, withCheckedContinuation)
App key location	AndroidManifest.xml meta-data	Info.plist → DJISDKAppKey

The motion-planning maths (constant, trapezoidal and S-curve velocity profiles) and every endpoint's behaviour and JSON shape are preserved.

Project layout

DJIControlServer/
├── App/
│   ├── DJIControlServerApp.swift   # SwiftUI @main entry point
│   ├── AppDelegate.swift           # Registers the SDK + starts the server
│   └── Info.plist                  # DJI app key, permissions, MFi protocols
├── Models/
│   └── Models.swift                # CommandCompleted, DroneState, IMUState, enums
├── Server/
│   ├── HTTPServer.swift            # Embedded HTTP/1.1 server (Network framework)
│   ├── Router.swift                # `{param}` path routing
│   └── NetworkInfo.swift           # Wi-Fi IPv4 lookup for the UI
├── Drone/
│   ├── DroneController.swift           # SDK connection + flight state
│   ├── DroneController+DJIDelegates.swift  # SDK/flight/battery callbacks
│   ├── DroneController+Routes.swift        # Endpoint registration + handlers
│   ├── DroneController+Motion.swift        # Velocity-profile motion planning
│   └── DroneController+Camera.swift        # Camera & gimbal commands
└── UI/
    └── ContentView.swift           # Status screen

Building

The project is tracked as plain source plus an XcodeGen spec and a CocoaPods Podfile, so no binary .xcodeproj is committed.

1. Install the tooling (one time):

   brew install xcodegen
   sudo gem install cocoapods   # or: brew install cocoapods

2. Generate the Xcode project:

   xcodegen generate

3. Install the DJI SDK pod and create the workspace:

   pod install

4. Open DJIControlServer.xcworkspace in Xcode.
5. In DJIControlServer/App/Info.plist, replace YOUR-DJI-APP-KEY-HERE with an app key generated on the DJI developer portal. The key must be registered against the bundle identifier com.rrc.djiControlServer (or change both to match).
6. Select your team for code signing, build, and install on an iOS device.

The DJI Mobile SDK requires a physical device connected to a DJI remote controller (or supported aircraft). It does not run in the iOS Simulator.

Usage

Launch the app and connect the iOS device to a DJI remote controller. Once the drone is connected, all endpoints are available at the device's IP on port 8080 (shown on screen).

curl http://<device-ip>:8080/            # -> Connected
curl http://<device-ip>:8080/takeoff
curl http://<device-ip>:8080/moveForward/1.5

Endpoints

All endpoints are GET requests, identical to the original server.

Connection

• / — connection test, returns Connected.

Takeoff and landing

• /takeoff, /land, /confirmLanding
• /isLandingProtectionEnabled, /enableLandingProtection, /disableLandingProtection

Control modes

• /getControlMode, /setControlMode/{mode} — mode is POSITION or VELOCITY (default POSITION).

Motion planning settings

• /getMaxSpeed, /setMaxSpeed/{speed} (m/s)
• /getMaxAngularSpeed, /setMaxAngularSpeed/{speed} (deg/s)
• /getVelocityProfile, /setVelocityProfile/{profile} — CONSTANT, TRAPEZOIDAL or S_CURVE (default CONSTANT).

IMU state reading

• /startCollectingIMUState/{interval}, /stopCollectingIMUState
• /getCollectedIMUStates, /clearCollectedIMUStates, /getCurrentIMUState

Positional movement and rotation (only in POSITION mode)

• /moveForward/{dist}, /moveBackward/{dist}, /moveLeft/{dist}, /moveRight/{dist}
• /moveUp/{dist}, /moveDown/{dist}
• /rotateClockwise/{angle}, /rotateCounterClockwise/{angle}

Velocity control (only in VELOCITY mode)

• /startVelocityControl, /stopVelocityControl
• /setVelocityCommand/{xVel}/{yVel}/{zVel}/{yawVel}, /getCurrentVelocityCommand

Camera and gimbal

• /captureShot, /startVideoRecording, /stopVideoRecording, /capturePanorama
• /pitchGimbal/{angle}, /fetchPreviewFromIndex/{n}

Other

• /getHeading — heading relative to true north.
• /getAltitude — ultrasonic height in metres (when the sensor is active).

Caveats

These carry over from the original project, plus a couple specific to iOS:

1. All motion commands are open-loop, so distances are approximate. The CONSTANT profile tracks the requested distance best; TRAPEZOIDAL and S_CURVE are smoother but accumulate more error.
2. confirmLanding behaves as expected in the DJI simulator but may differ on a physical drone.
3. No GPS-based functionality is implemented — this is for indoor, GPS-denied use.
4. /reboot is implemented for API parity but returns an error: the iOS Mobile SDK does not expose a public flight-controller reboot (the Android SDK does).
5. The camera/gimbal endpoints target Mobile SDK 4.16 API names. If you build against a different SDK version, a few method/enum names (setFlatMode, DJIFlatCameraMode, DJIGimbalRotation) may need adjusting.
6. iOS only serves the local-network API while the app is in the foreground (or briefly via the external-accessory background mode). Keep the app on-screen during a flight session.