将Alamofire与.publishDecodable结合使用

Question

我需要将.publishDecodable与Result一起使用，我遵循了instructions，但是遇到了这个错误：“无法推断通用参数't'闭包”

@Published var loginModel: [LoginModel] = [LoginModel]()

var cancellation: AnyCancellable?

func request<T: Codable>(_ url: String, method: HTTPMethod = .get, headers: HTTPHeaders? = nil, parameters: Codable? = nil) -> AnyPublisher<Result<T, AFError>, Never> {
    let publisher = AF.request(url, method: method, headers: headers)
        .validate()
        .publishDecodable(type: T.self)
    return publisher.result()
}

 func login(email: String, password: String) {
    let parameters = LoginParameters(
        email: email,
        password: password
    )

    cancellation = request(serverURL + "login", method: .post, parameters: parameters)
        .sink { [self] response in
            switch response {
            case .success:
                loginModel = response.value()
            case .failure(error):
                print(error)
            }
        }
}

Answer 1

您应该帮助编译器通过提供您期望的T的类型来推断response的类型。例如，您对request(_:method:headers:parameters:)函数的调用可能看起来像这样：

cancellation = request(serverURL + "login", method: .post, parameters: parameters)
    .sink { [self] (response: Result<[LoginModel], AFError>) in
        switch response {
        case .success(let value):
            self.loginModel = value
        case .failure(let error):
            print(error)
        }
    }

或者，如果您愿意，也可以指定request(_:method:headers:parameters:)函数的返回类型，如下所示：

let publisher: AnyPublisher<Result<[LoginModel], AFError>, Never>
publisher = request(serverURL + "login", method: .post, parameters: parameters)
cancellation = publisher.sink { [self] response in
    switch response {
    case .success(let value):
        self.loginModel = value
    case .failure(let error):
        print(error)
    }
}