iOS - FileManager拡張のベストプラクティス

Question

私はこれを作成しましたFileManagerextensionこのextensionで、私はそうのようなファイル階層を作成したい：

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これは、FileManagerextensionのコードです。これは、アプリケーションが起動するとすぐにapp delegateに呼び出されます。次に、このコードを使用して、常にpathのフォルダを取得します。

これは、この階層を作成し、必要なときにパスを取得するための良い方法ですか？これはいい練習ですか？

extension FileManager { 
    static func createOrFindApplicationDirectory() -> URL? { 
     let bundleID = Bundle.main.bundleIdentifier 
     // Find the application support directory in the home directory. 
     let appSupportDir = self.default.urls(for: .applicationSupportDirectory, in: .userDomainMask) 

     guard appSupportDir.count > 0 else { 
      return nil 
     } 

     // Append the bundle ID to the URL for the Application Support directory. 
     let dirPath = appSupportDir[0].appendingPathComponent(bundleID!) 

     // If the directory does not exist, this method creates it. 
     do { 
      try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil) 
      return dirPath 
     } catch let error { 
      print("Error creating Application Support directory with error: \(error)") 
      return nil 
     } 
    } 

    static func createOrFindFavoritesDirectory() -> URL? { 
     guard let appSupportDir = createOrFindApplicationDirectory() else { 
      return nil 
     } 

     let dirPath = appSupportDir.appendingPathComponent("Favorites") 

     // If the directory does not exist, this method creates it. 
     do { 
      try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil) 
      return dirPath 
     } catch let error { 
      print("Error creating Favorites directory with error: \(error)") 
      return nil 
     } 
    } 

    static func createOrFindFeedDirectory() -> URL? { 
     guard let appSupportDir = createOrFindFavoritesDirectory() else { 
      return nil 
     } 

     let dirPath = appSupportDir.appendingPathComponent("Feed") 

     // If the directory does not exist, this method creates it. 
     do { 
      try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil) 
      return dirPath 
     } catch let error { 
      print("Error creating Favorites directory with error: \(error)") 
      return nil 
     } 
    } 

    static func currentImagesDirectory() -> URL? { 
     guard let feedDir = createOrFindFeedDirectory() else { 
      return nil 
     } 

     let dirPath = feedDir.appendingPathComponent("Images") 

     // If the directory does not exist, this method creates it. 
     do { 
      try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil) 
      return dirPath 
     } catch let error { 
      print("Error creating Images directory with error: \(error)") 
      return nil 
     } 
    } 
} 

Answer 1

それはかなり良いように見えますが、あなたはコードのビットを組み合わせて、より良いエラーチェックを持つことができます：

extension FileManager { 
    static func createOrFindApplicationDirectory() -> URL? { 
     guard let bundleID = Bundle.main.bundleIdentifier else { 
      return nil 
     } 

     // Find the application support directory in the home directory. 
     let appSupportDirArray = self.default.urls(for: .applicationSupportDirectory, in: .userDomainMask) 

     guard let appSupportDir = appSupportDirArray.first else { 
      return nil 
     } 

     // Append the bundle ID to the URL for the Application Support directory. 
     let dirPath = appSupportDir.appendingPathComponent(bundleID) 

     // If the directory does not exist, this method creates it. 
     do { 
      try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil) 
      return dirPath 
     } catch let error { 
      print("Error creating Application Support directory with error: \(error)") 
      return nil 
     } 
    } 

    static func createOrFindDirectory(named name: String) -> URL? { 
     guard let appSupportDir = createOrFindApplicationDirectory() else { 
      return nil 
     } 

     let dirPath = appSupportDir.appendingPathComponent(name) 

     // If the directory does not exist, this method creates it. 
     do { 
      try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil) 
      return dirPath 
     } catch let error { 
      print("Error creating \(name) directory with error: \(error)") 
      return nil 
     } 
    } 

    static func currentImagesDirectory() -> URL? { 
     guard let feedDir = createOrFindDirectory(named: "Feed") else { 
      return nil 
     } 

     let dirPath = feedDir.appendingPathComponent("Images") 

     // If the directory does not exist, this method creates it. 
     do { 
      try self.default.createDirectory(at: dirPath, withIntermediateDirectories: true, attributes: nil) 
      return dirPath 
     } catch let error { 
      print("Error creating Images directory with error: \(error)") 
      return nil 
     } 
    } 
}