使用URLSession并發處理后端驗證錯誤

是否可以解碼來自物件內部具有未知密鑰的服務器的錯誤回應？我將如何處理這樣的回應？

現在我像這樣在 URLSession 上做了一個擴展

extension URLSession {
    func post<T: Decodable, U: Encodable>(
        _ type: T.Type = T.self,
        data: U,
        from url: URL,
        keyDecodingStrategy: JSONDecoder.KeyDecodingStrategy = .convertFromSnakeCase
    ) async throws  -> T {
        var request = URLRequest(url: url)
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        request.httpMethod = "POST"
        
        let body = try JSONEncoder().encode(data)
        
        let token = UserDefaults.standard.string(forKey: "AccessToken")
        if token != nil {
            request.setValue("Bearer \(token!)", forHTTPHeaderField: "Authorization")
        }
        do {
            let (data, response) = try await upload(for: request, from: body)
            let decoder = JSONDecoder()
            decoder.keyDecodingStrategy = keyDecodingStrategy

            let decoded = try decoder.decode(T.self, from: data)
            return decoded
        } catch {
            print(error)
            throw error
        }
        
    }
}

這樣我可以向后端發出 POST 請求并取回解碼的物件所以當我嘗試登錄時，我可以這樣做：

    func login(email: String, password: String) async {
        let body = LoginRequest(email: email, password: password)
        let url = URL(string: "https://api.junoreader.com/api/auth/login")!
        do {
            let response = try await URLSession.shared.post(DetailModel<UserModel>.self, data: body, from: url)
            setUser(data: response.data)
        } catch {
            print("api error")
            print(error)
        }
    }

回應的樣子

struct DetailModel<T: Codable>: Codable {
    var data: T
}
struct UserModel: Codable, Identifiable, ObservableObject {
    let id: Int
    let firstName: String
    let lastName: String
    let username: String
    let bio: String

    var name: String {
        return "\(firstName ?? "") \(lastName ?? "")"
    }
}

但是，當登錄憑據錯誤時，服務器會使用 403 回應 JSON 物件，如下所示

{
  "data": {
    "errors": {
      "login": [
        "Email/password do not match."
      ]
    }
  }
}

資料和錯誤鍵始終存在，但根據我所做的請求和后端的驗證，“登錄”可能會有所不同。所以“錯誤”也可能有多個鍵。

解碼此類錯誤物件的最佳方法是什么？如何在“post”函式中處理這些錯誤？同樣，當錯誤發生而不是立即拋出錯誤時，swift仍在嘗試解碼資料。

uj5u.com熱心網友回復：

您可以為 API 錯誤定義一個物件：

struct ApiErrorPayload: Decodable {
    let errors: [String: [String]]
}

然后Error，您可以定義一個列舉，以便您可以拋出此錯誤（以及一般 HTTP 錯誤）：

enum ApiError: Error {
    case serviceError(ApiErrorPayload)
    case httpError(Data, HTTPURLResponse)
}

然后您可以定義您的post方法來檢查狀態代碼并解碼您的錯誤物件或您的ApiErrors：

extension URLSession {
    func post<T: Decodable, U: Encodable>(
        _ type: T.Type = T.self,
        data: U,
        from url: URL,
        keyDecodingStrategy: JSONDecoder.KeyDecodingStrategy = .convertFromSnakeCase
    ) async throws  -> T {
        var request = URLRequest(url: url)
        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
        request.httpMethod = "POST"

        let body = try JSONEncoder().encode(data)

        if let token = UserDefaults.standard.string(forKey: "AccessToken") {
            request.setValue("Bearer "   token, forHTTPHeaderField: "Authorization")
        }

        let (data, response) = try await upload(for: request, from: body)
        guard let response = response as? HTTPURLResponse else {
            throw URLError(.badServerResponse)
        }

        let decoder = JSONDecoder()
        decoder.keyDecodingStrategy = keyDecodingStrategy

        switch response.statusCode {
        case 200 ..< 300:
            return try decoder.decode(T.self, from: data)

        case 400 ..< 500:
            let payload = try decoder.decode(ApiErrorPayload.self, from: data)
            throw ApiError.serviceError(payload)

        default:
            throw ApiError.httpError(data, response)
        }
    }
}

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