AsyncAction implementation for Suas that performs a URL request

URLSessionAsyncAction.swift

/// Callback called when URLSession operation completes
public typealias URLSessionActionCompletionBlock = (Data?, URLResponse?, Error?, DispatchFunction) -> Void


/// URL Session `AsyncAction` implementation to fetch data from the network asynchronously. Requires `AsyncMiddleware` to be added to the store.
///
/// # Example
///
/// ```
/// let action = URLSessionAsyncAction(url: ...) { data, response, error, dispatch in
///   // Parse data and prepare models
///   dispatch(DataFetchedAction(parsed))
/// }
/// ```
public struct URLSessionAsyncAction: AsyncAction {

  private let urlSession: URLSession
  private let urlRequest: URLRequest
  private let completionBlock:  URLSessionActionCompletionBlock

  /// Create a URLSession AsyncAction
  ///
  /// - Parameters:
  ///   - url: the url to fetch
  ///   - urlSession: (optional) the url session to use. When not set a default one will be used.
  ///   - completionBlock: callback to call when the url operation is ended. In this block `dispatch` is used to dispatch new actions
  /// - Returns: an async action to dispatch
  public init(url: URL,
              urlSession: URLSession = URLSession(configuration: .default),
              completionBlock: @escaping URLSessionActionCompletionBlock) {
    self.init(urlRequest: URLRequest(url: url), urlSession: urlSession, completionBlock: completionBlock)
  }

  /// Create a URLSession AsyncAction
  ///
  /// - Parameters:
  ///   - urlRequest: the url request to fetch
  ///   - urlSession: (optional) the url session to use. When not set a default one will be used.
  ///   - completionBlock: callback to call when the url operation is ended. In this block `dispatch` is used to dispatch new actions
  /// - Returns: an async action to dispatch
  public init(urlRequest: URLRequest,
              urlSession: URLSession = URLSession(configuration: .default),
              completionBlock: @escaping URLSessionActionCompletionBlock) {
    self.urlRequest = urlRequest
    self.urlSession = urlSession
    self.completionBlock = completionBlock
  }

  public func execute(getState: @escaping GetStateFunction, dispatch: @escaping DispatchFunction) {
    // Perform a data task with the reuest
    urlSession.dataTask(with: urlRequest) { data, response, error in
      // When its done, call the completion block                                      
      self.completionBlock(data, response, error, dispatch)
      }.resume()
  }
}