SwiftUI/Other Projects/GitHub Search/GitHubSearchWithSwiftUI/Extension/URLSession.Combine.swift

//
//  URLSession.Combine.swift
//  GitHubSearchWithSwiftUI
//
//  Created by marty-suzuki on 2019/06/05.
//  Copyright © 2019 jp.marty-suzuki. All rights reserved.
//

import Combine
import Foundation

extension URLSession: CombineCompatible {}

extension CombineExtension where Base == URLSession {

    func send(request: URLRequest) -> AnyPublisher<Data, URLSessionError> {

        base.dataTaskPublisher(for: request)
            .mapError { URLSessionError.urlError($0) }
            .flatMap { data, response -> AnyPublisher<Data, URLSessionError> in
                guard let response = response as? HTTPURLResponse else {
                    return .fail(.invalidResponse)
                }

                guard 200..<300 ~= response.statusCode else {
                    return .fail(.serverErrorMessage(statusCode: response.statusCode,
                                                     data: data))
                }

                return .just(data)
            }
            .eraseToAnyPublisher()
    }
}

enum URLSessionError: Error {
    case invalidResponse
    case serverErrorMessage(statusCode: Int, data: Data)
    case urlError(URLError)
}