Updating CoreML models in an iOS app typically involves fetching a new model file, parsing it, and then updating the CoreML model with the new version. JSON parsing can be used to extract necessary information from the fetched JSON file. Below is a step-by-step guide using Swift:
Fetch and Parse JSON
Fetch a JSON file containing information about the updated CoreML model, including its download URL, version, etc.
import Foundation
// Replace with the URL of your JSON file
let jsonURLString = "https://example.com/model_info.json"
if let url = URL(string: jsonURLString),
let data = try? Data(contentsOf: url),
let json = try? JSONSerialization.jsonObject(with: data, options: []) as? [String: Any] {
// Extract information from the JSON
if let newModelURLString = json["new_model_url"] as? String,
let newModelVersion = json["new_model_version"] as? String {
// Continue with the next steps
updateCoreMLModel(with: newModelURLString, version: newModelVersion)
}
}
Download and Save New Model:
Download the new CoreML model file from the provided URL and save it locally.
func updateCoreMLModel(with modelURLString: String, version: String) {
guard let modelURL = URL(string: modelURLString),
let modelData = try? Data(contentsOf: modelURL) else {
print("Failed to download the new model.")
return
}
// Save the new model to a local file
let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let newModelURL = documentsDirectory.appendingPathComponent("newModel.mlmodel")
do {
try modelData.write(to: newModelURL)
print("New model downloaded and saved.")
updateCoreMLModelWithNewVersion(newModelURL, version: version)
} catch {
print("Error saving new model: \(error.localizedDescription)")
}
}
Update CoreML Model:
Load the new CoreML model and update the app's model.
import CoreML
func updateCoreMLModelWithNewVersion(_ modelURL: URL, version: String) {
do {
// Load the new CoreML model
let newModel = try MLModel(contentsOf: modelURL)
// Replace the existing CoreML model with the new version
// Assuming your model has a custom CoreMLModelManager class
CoreMLModelManager.shared.updateModel(newModel, version: version)
print("CoreML model updated to version \(version).")
} catch {
print("Error loading new CoreML model: \(error.localizedDescription)")
}
}
Handle Model Updates in App:
Depending on your app's architecture, you might want to handle the model update in a dedicated manager or service. Ensure that you handle the update gracefully and consider user experience during the update process.
Make sure to replace placeholder URLs and customize the code according to your actual implementation. Additionally, handle errors appropriately and test thoroughly to ensure a smooth update process.
