SAPMLModelManager

public class SAPMLModelManager

The SAPMLModelManager is a convenience class for distributing new versions of Core ML models to the device and handling the local compilation and persistence of the Core ML models. The Core ML models are distributed from SAP Mobile Services as Client Resource files. The Core ML models are distributed remotely allowing the app to use the updated versions of the models, without requiring a re-distribution of the app itself. It is also possible to distribute the initial version of the model within the app and have subsequent versions distributed remotely. SAPMLModelManager provides APIs for performing operations like download, update, delete & list of Core ML models stored on File System.

SAPMLModelManager follows singleton design pattern. So to invoke SAPMLModelManager APIs use SAPMLModelManager.shared instance.

Example use

//Configure `SAPMLModelManager` by setting the `sapUrlSession` and `cpmsSettingsParameters` properties which will be used for downloading the Core ML Models from SAP Mobile Services
   SAPMLModelManager.shared.sapUrlSession = //set the fully configured SAPURLSession
   SAPMLModelManager.shared.cpmsSettingsParameters = //set the cpmsSettingsParameters
   SAPMLModelManager.shared.delegate = MyMLModelManagerDelegate() //set the delegate that will receive a callback on download completion
//Specify the name of the Core ML model that needs to be downloaded from Mobile Services using SAPMLModel
   let helloCPMS = SAPMLModel(named:"HelloCPMSModel" , localURL: nil)
//Trigger download of the model
   SAPMLModelManager.shared.download(model: helloCPMS)
//Handle completion callback received on SAPMLModelManagerDelegate
func sapMLModelManager(_ manager: SAPMLModelManager, model: SAPMLModel?, didCompleteWithError error: SAPMLModelManagerError?) {
    if let err = error {
        switch err {
        case .compilationError(let compilationError):
            // Handle model compilation error
        case .downloadUnderway:
            // Handle model compilation error
        case .other(let otherError):
            // Handle otehr errors
        case .server(let serverError):
            // Handle server error
        case .cpmsSettingsMissing:
            // Handle CPMS Settings missing error
        case .modelNotFound:
            // Handle model not found error

        }
    }
    else {
        // Model downloaded/updated successfully
    }
}
//Access the downloaded and compiled ML model
    do {
       try SAPMLModelManager.shared.mlModel(for: helloCPMS)
    }
    catch _ {
       //Error Handling
    }

Modifications required in AppDelegate

//The SAPMLModelManager downloads the latest version of the Core ML model file that is available as a Client Resource on Mobile Services. It is recommended that the download call is hooked into the AppDelegate `applicationWillEnterForeground` lifecycle method so that the app gets to use the latest version.
    func applicationWillEnterForeground(_: UIApplication) {
        let helloCPMS = SAPMLModel(named:"HelloCPMSModel" , localURL: nil)
        SAPMLModelManager.shared.download(model: helloCPMS)
    }
//As the `SAPMLModelManager` performs download of Core ML models in the background, the handleEventsForBackgroundURLSession event must be forwarded to the SDK to handle
completion of tasks when the application is launched or resumed in the background
func application(_ application: UIApplication, handleEventsForBackgroundURLSession identifier: String, completionHandler: @escaping () -> Void) {
    AppDelegateDispatcher.application(application, handleEventsForBackgroundURLSession: identifier, completionHandler: completionHandler)
}

Example - Starting off with a local Core ML model within the app, updated subsequently with remotely distributed models.

//The Core ML model located at `localURL` will be available using the `mlModel(..)` function.
   let helloCPMS = SAPMLModel(named:"HelloCPMSModel" , localURL: Bundle.main.url(forResource: "myModel", withExtension: "mlmodelc"))
   SAPMLModelManager.shared.download(model: helloCPMS)
   try? SAPMLModelManager.shared.mlModel(for: helloCPMS) //returns local model

 //If a new version of the Core ML model is uploaded on Mobile Services Client Resources, it will be downloaded and compiled.
   let helloCPMS = SAPMLModel(named:"HelloCPMSModel" , localURL: Bundle.main.url(forResource: "myModel", withExtension: "mlmodelc"))
   SAPMLModelManager.shared.download(model: helloCPMS)
   try? SAPMLModelManager.shared.mlModel(for: helloCPMS) //returns remote model