如何在SwiftUI中获得来自URLSession的响应

import SwiftUI
import Combine

struct ContentView: View {
    @StateObject private var viewModel = URLSessionViewModel()
    
    var body: some View {
        VStack {
            if let response = viewModel.response {
                Text("Response: \(response)")
            } else if let error = viewModel.error {
                Text("Error: \(error.localizedDescription)")
            } else {
                ProgressView()
            }
        }
        .onAppear {
            viewModel.fetchData()
        }
    }
}

class URLSessionViewModel: ObservableObject {
    @Published var response: String?
    @Published var error: Error?
    
    private var cancellables = Set<AnyCancellable>()
    
    func fetchData() {
        guard let url = URL(string: "https://example.com/api/data") else {
            return
        }
        
        URLSession.shared.dataTaskPublisher(for: url)
            .map(\.data)
            .decode(type: ResponseModel.self, decoder: JSONDecoder())
            .receive(on: DispatchQueue.main)
            .sink { completion in
                switch completion {
                case .finished:
                    break
                case .failure(let error):
                    self.error = error
                }
            } receiveValue: { response in
                self.response = response.data
            }
            .store(in: &cancellables)
    }
}

struct ResponseModel: Codable {
    let data: String
}