[SwiftUI Project] 재사용 가능한 NetworkingManager.. with Combine

코인리스트를 받아올 때 네트워크 작업을 하는 CoinDataService.swift 를 재사용 가능하게 작성합니다.

앱이 커지게 되면서 네트워킹 코드를 반복해서 쓰게 될 일을 줄여줍니다. 

 

업데이트 전의 CoinDataService.swift

import Foundation
import Combine

class CoinDataService {
    
    @Published var allCoins: [CoinModel] = []
    
    var coinSubscription: AnyCancellable?
    
    init() {
        getCoin()
    }
    
    private func getCoin() {
        
        guard let url = URL(string: "https://api.coingecko.com/api/v3/coins/markets?vs_currency=usd&order=market_cap_desc&per_page=250&page=1&sparkline=true&price_change_percentage=24h") else { return }
        
        coinSubscription = URLSession.shared.dataTaskPublisher(for: url)
            .subscribe(on: DispatchQueue.global(qos: .default))
            .tryMap { (output) -> Data in
                guard let response = output.response as? HTTPURLResponse,
                      response.statusCode == 200 else {
                          throw URLError(.badServerResponse)
                      }
                return output.data
            }
            .receive(on: DispatchQueue.main)
            .decode(type: [CoinModel].self, decoder: JSONDecoder())
            .sink { (completion) in
                switch completion {
                case .finished:
                    break
                case .failure(let error):
                    print(error.localizedDescription)
                }
            } receiveValue: { [weak self] (returnCoins) in
                self?.allCoins = returnCoins
                self?.coinSubscription?.cancel()
            }
    }
}

 

업데이트 후의 CoinDataService.swift

import Foundation
import Combine

class CoinDataService {
    
    @Published var allCoins: [CoinModel] = []
    
    var coinSubscription: AnyCancellable?
    
    init() {
        getCoin()
    }
    
    private func getCoin() {
        
        guard let url = URL(string: "https://api.coingecko.com/api/v3/coins/markets?vs_currency=usd&order=market_cap_desc&per_page=250&page=1&sparkline=true&price_change_percentage=24h") else { return }
        
        coinSubscription = NetWorkingManager.download(url: url)
            .decode(type: [CoinModel].self, decoder: JSONDecoder())
            .sink(receiveCompletion: NetWorkingManager.handleCompletion, receiveValue: { [weak self] (returnCoins) in
                self?.allCoins = returnCoins
                self?.coinSubscription?.cancel()
            })
    }
}

 

새롭게 추가된 NetworkingManager.swift

import Foundation
import Combine

class NetWorkingManager {
    
    enum NetworkingError: LocalizedError {
        case badURLResponse(url: URL)
        case unknown
        
        var errorDescription: String? {
            switch self {
            case .badURLResponse(url: let url): return "[🔥] Bad response form URL: \(url)"
                // \(url )로 어떤 url에서 에러가 발생했는지 알 수 있습니다.
            case .unknown: return "[⚠️] Unknown error occured"
            }
        }
    }
    
    static func download(url: URL) -> AnyPublisher<Data, Error> {
        return URLSession.shared.dataTaskPublisher(for: url)
            .subscribe(on: DispatchQueue.global(qos: .default))
            .tryMap({ try handleURLResponse(output: $0, url: url) })
            .receive(on: DispatchQueue.main)
            .eraseToAnyPublisher()
    }
    
    static func handleURLResponse(output: URLSession.DataTaskPublisher.Output, url: URL) throws -> Data {
        guard let response = output.response as? HTTPURLResponse,
              response.statusCode == 200 else {
                  throw NetworkingError.badURLResponse(url: url)
              }
        return output.data
    }
    
    static func handleCompletion(completion: Subscribers.Completion<Error>) {
        switch completion {
        case .finished:
            break
        case .failure(let error):
            print(error.localizedDescription)
        }
    }
}

NetworkingManager 문서를 보면 dataTaskPublisher를 통해 데이터를 다운로드 하는 코드, 에러 핸들링 코드가 함수로 정리되어 있습니다.

 

덕분에 앞으로 네트워킹 코드를 작성할 때 수고를 줄일 수 있겠네요!