export_images_to_zip for medium post

export _images_to_zip.ex

def export_images_to_zip(data, path) do
  images_to_download = Enum.map(data, fn datum ->
    %{url: datum.image, name: datum.name}
  end)
  case images_to_download do
    [] -> nil
    list ->
      zip_path = path<>"/images"
      :ok = File.mkdir_p!(zip_path)
      download_images_in_batch(list, zip_path)
  end
end

def download_images_in_batch(list_of_images, zip_path) do
  list_of_images
    |> Stream.chunk_every(5, 5, [])
    |> Stream.each(fn item ->
      download_images(item, zip_path)
    end)
    |> Enum.to_list
end

def download_images(list_of_images, zip_path) do
  try do
    list_of_images
    |> Enum.map(&Task.async(fn -> download_image(&1) end))
    |> Enum.map(&Task.await(&1, 50000))
    |> Enum.map(fn item ->
      case item do
        {:ok, name, body} ->
          file_path = zip_path<>"/"<>name
          File.write!(file_path, body)
          file_path
        {:error, error} ->
          IO.inspect error
          nil
      end
    end)
  catch
    :exit, error ->
      Logger.error "Error while downloading batches #{inspect error}"
  end
end

def download_image(%{url: url, name: name}) do
  case HTTPotion.get url, [timeout: 50000] do
    %HTTPotion.Response{body: body,status_code: 200} ->
      {:ok, name<>"."<>get_image_extension(url), body}
    %HTTPotion.ErrorResponse{message: message} ->
      {:error, message}
    error ->
      {:error, error}
  end
end

defp get_image_extension(url) do
  String.split(url, "/") |> List.last() |> String.split(".") |> List.last()
end