Question

我正在编写一个Router类来驱动我的API（CRUD），如Alamofire文档中所规定的那样，令人讨厌的是，我最终反复重复相同的代码行。这是枚举的一部分：

enum Router: URLRequestConvertible {
  static let baseURLString = "http://xxx.xxx.xxx.xxx"

  case ReadFeed([String: AnyObject])
  case CreateUser([String: AnyObject])
  case LogIn([String:AnyObject])
  case CreatePost([String:AnyObject])
  case ReadUser(id: String, parameters: [String:AnyObject])
  case ListUsers([String:AnyObject])
  case UpdateUser([String: AnyObject])
  case DestroyUser(String)
  case ReadImage(String)
  case Subscribe(String, to: String)

  var method: Alamofire.Method {
    switch self {
    case .CreateUser, .CreatePost:
      return .POST
    case .ReadUser, .ListUsers, .ReadImage, .ReadFeed, .SearchUser:
      return .GET
    case .UpdateUser:
      return .PUT
    case .DestroyUser:
      return .DELETE
    case .LogIn:
      return .POST
    }
  }

  var path: String {
    switch self {
    case .ReadFeed:
      return "/feed"
    case .CreateUser:
      return "/users"
    case .CreateColumn:
      return "/columns"
    case .UploadImage:
      return  "/profilepictures"
    case .ListUsers:
      return "/users"
    case .ReadUser(let id, _):
      return "/users/\(id)"
    case .CreatePost:
      return "/posts"
    case .LogIn:
      return "/users/login"
    case .ReadImage(let ownerID):
      return "/image/\(ownerID)"
    case .Subscribe(let user, _):
      return "/users/\(user)"
    case .UpdateUser(let username, _):
      return "/users/\(username)"
    case .DestroyUser(let username):
      return "/users/\(username)"
    }
  }

  // MARK: URLRequestConvertible

  var URLRequest: NSMutableURLRequest {
    let URL = NSURL(string: Router.baseURLString)!
    let mutableURLRequest = NSMutableURLRequest(URL: URL.URLByAppendingPathComponent(path))
    mutableURLRequest.HTTPMethod = method.rawValue

    switch self {
    case .CreateUser(let parameters):
      return Alamofire.ParameterEncoding.JSON.encode(mutableURLRequest, parameters: parameters).0
      return Alamofire.ParameterEncoding.JSON.encode(mutableURLRequest, parameters: parameters).0
    case .CreatePost(let parameters):
      return Alamofire.ParameterEncoding.JSON.encode(mutableURLRequest, parameters: parameters).0
    case .UploadImage( _, let image, let parameters):
      mutableURLRequest.HTTPBody = UIImageJPEGRepresentation(image, 1)
       return Alamofire.ParameterEncoding.URL.encode(mutableURLRequest, parameters: parameters).0
    case .UpdateUser(_, let parameters):
      return Alamofire.ParameterEncoding.URL.encode(mutableURLRequest, parameters: parameters).0
    case .ListUsers(let parameters):
      return Alamofire.ParameterEncoding.URL.encode(mutableURLRequest, parameters: parameters).0
    case .ReadFeed(let parameters):
      return Alamofire.ParameterEncoding.URL.encode(mutableURLRequest, parameters: parameters).0
    case .ReadUser(_, let parameters):
      return Alamofire.ParameterEncoding.URL.encode(mutableURLRequest, parameters: parameters).0
    case .LogIn(let parameters):
      return Alamofire.ParameterEncoding.URL.encode(mutableURLRequest, parameters: parameters).0
    case .Subscribe(_, let newSubscription):
      let parameters: [String:AnyObject] = ["subscriptions": ["$push": newSubscription]]
      return Alamofire.ParameterEncoding.JSON.encode(mutableURLRequest, parameters: parameters).0
    default:
      return mutableURLRequest
    }
  }
}

如您所见，公式

case .XXX(let parameters):
  return Alamofire.ParameterEncoding.URL.encode(mutableURLRequest, parameters: parameters).0

重复次数和次数。有没有办法避免这种情况？

Answer 1

在所有情况下，您似乎都有parameters，因此可能不应与每个案例相关联。类似于此的结构可能很有用：

struct RouterInfo {
    let type: Router
    let parameters: [String:AnyObject]
}

然后只有enum Router中的某些案例可能会有一些特定于这些案例的关联值。

然后，您的var URLRequest应该是结构的一部分。

Answer 2

你可以定义更多名为'parameters'的变量，它是[String：AnyObject]的一种类型吗？并为每个案例返回这些参数。

请注意，.get服务需要参数为nil，如果.post服务没有参数，则返回[：]（空字典）

var parameters: [String: AnyObject]? {
    switch self {
    case .login(let username, let password):
        return [
            "username": username,
            "password": password
        ]
    case .getUserInfo(let userID):
        return ["userID": userID]
    default: 
        return nil
    }
}

然后在mutableURLRequest中调用此变量

var URLRequest: NSMutableURLRequest {
    let URL = NSURL(string: Router.baseURLString)!
    let mutableURLRequest = NSMutableURLRequest(URL: URL.URLByAppendingPathComponent(path))
    mutableURLRequest.HTTPMethod = method.rawValue

    // Get your parameters via calling the variable
    return Alamofire.ParameterEncoding.JSON.encode(mutableURLRequest, parameters: parameters).0
}

Answer 3

我认为你可以做这样的事情

 switch self {
case .CreateUser(let parameters):
  return Alamofire.ParameterEncoding.JSON.encode(mutableURLRequest, parameters: parameters).0
  return Alamofire.ParameterEncoding.JSON.encode(mutableURLRequest, parameters: parameters).0
case .CreatePost(let parameters):
  return Alamofire.ParameterEncoding.JSON.encode(mutableURLRequest, parameters: parameters).0
case .UploadImage( _, let image, let parameters):
  mutableURLRequest.HTTPBody = UIImageJPEGRepresentation(image, 1)
   return Alamofire.ParameterEncoding.URL.encode(mutableURLRequest, parameters: parameters).0
case .UpdateUser(_, let parameters), .ListUsers(let parameters), .ReadFeed(let parameters), .ReadUser(_, let parameters), case .LogIn(let parameters):
  return Alamofire.ParameterEncoding.URL.encode(mutableURLRequest, parameters: parameters).0
case .Subscribe(_, let newSubscription):
  let parameters: [String:AnyObject] = ["subscriptions": ["$push": newSubscription]]
  return Alamofire.ParameterEncoding.JSON.encode(mutableURLRequest, parameters: parameters).0
default:
  return mutableURLRequest
}

通过这种方式，您将获得最少的重复次数。

当枚举情况具有相同的关联值时，避免重复的代码行？

3 个答案: