Question

这是我的一段代码，

protocol Configuration {

    static var url: String { get }
    static var username: String { get }
    static var password: String { get }
}

protocol Server {

    associatedtype Profile: Configuration
    associatedtype Payment: Configuration
    associatedtype Images: Configuration
}

struct Development: Server {

    struct Profile: Configuration {

        static var url: String { return "http://google.com" }
        static var username: String { return "abc" }
        static var password: String { return "xyz" }
    }

    struct Payment: Configuration {

        static var url: String { return "http://bing.com" }
        static var username: String { return "abc" }
        static var password: String { return "xyz" }
    }

    struct Images: Configuration {

        static var url: String { return "http://duckduckgo.com" }
        static var username: String { return "abc" }
        static var password: String { return "xyz" }
    }
}

struct Production: Server {

    struct Profile: Configuration {

        static var url: String { return "http://amazon.com" }
        static var username: String { return "pqr" }
        static var password: String { return "xyz" }
    }

    struct Payment: Configuration {

        static var url: String { return "http://facebook.com" }
        static var username: String { return "pqr" }
        static var password: String { return "xyz" }
    }

    struct Images: Configuration {

        static var url: String { return "http://orkut.com" }
        static var username: String { return "pqr" }
        static var password: String { return "xyz" }
    }
}

问题是我想获取我的'结构'（取决于我的环境）。我需要类似的东西，

struct Environment {

    static func current() -> Any:Server {

        if #DEBUG
            return Development
        #endif

        return Production
    }
}

但是不可能返回确认我的协议的特定类型。

对此或不同方法的任何建议都会有所帮助。

Answer 1

“发展”和“生产”是价值观，而不是类型。您不需要此处的协议，也不应使用它们。只需创建您需要的值并将其返回：

seguidores = followers[2]
datacount = seguidores.attrs['data-count']

Answer 2

您可以返回通用类型，或者只需执行以下操作：

struct Config {

  static var BaseURL: URL {
    switch Environment.current {
      case .debug:
        return URL(string: "https://...dev.com")!
      case .staging:
        return URL(string: "https://...staging.com")!
      case .release:
        return URL(string: "https://...production.com")!
      }
  }

}

Answer 3

只需返回Server，而不是Any:Server：

static func current() -> Server {

    if #DEBUG
        return Development
    #endif

    return Production
}

返回结构类型确认协议

3 个答案: