elixir - 在分块模式下保持 Elixir Plug 连接打开

Question

是否可以在分块状态下保持连接打开几秒钟？

在请求中，我创建了几个进程，假设需要 5 秒才能完成，之后我想通过 block 向客户端发送响应，但连接已关闭

我正在用 postman 测试这个，我有这个标题:

"Connection": "Keep-Alive", "Keep-Alive": "timeout=10000"

这是我最小化的应用程序，输出始终是“InitEnd”期望的结果是:“Init1234567789End”或类似这样的内容:

defmodule AlivePlug do
  import Plug.Conn

  def init(opts) do
    opts
  end

  def call(conn, _opts) do
    conn = send_chunked(conn, 200)
    # send initial chunk
    chunk(conn, "Init")

    pid = start_thread
    # create 10 async processes which does somthing for 5 seconds and then sends result via chunk
    1..10
    |> Enum.each(fn num -> 
      send pid, {conn, num}
    end)

    # send End as a symbol of last chunk
    chunk(conn, "End")
    conn
  end

  defp start_thread, do: spawn_link(fn -> thread_listener end)
  defp thread_listener do
    receive do
      {conn, num} ->
        :timer.sleep(5000)
        # problem is here :(
        # chunk returns {:error, :closed}
        {:error, :closed} = chunk(conn, "#{num}")
        thread_listener
      _ -> 
        thread_listener
    end
  end
end

Answer 1

作为解决方法，我定期使用 conn。

receive do
  ...
  after 3000 ->
    # avoid connection close.
    # execute `chunk(conn, ".")` every 3000ms
    chunk(conn, ".")
end

作为附加信息，chunk 的第二个参数不应为空字符串。