Session is empty when mount/3 is called the second time

[nileshtrivedi]

I ran into this when trying to create a simple token-based auth for the liveview.

This might be fixable by a custom endpoint which passes @session_options to the socket "/live", Phoenix.LiveView.Socket call. But it would be nice to have sessions working in liveview as expected in PhoenixPlayground.Endpoint which is missing this option.

[nileshtrivedi]

I added this demo script to demonstrate this problem of using sessions in liveviews.

When you run it, you can see that first mount prints this:

12:52:58.137 [info] GET /

12:52:58.140 [debug] Processing with LiveWithSession.Elixir.LiveWithSession/2
  Parameters: %{}
  Pipelines: [:browser]
[examples/demo_live_with_session.exs:21: LiveWithSession.mount/3]
session #=> %{"user_id" => "testuser"}

But then, when the connection is upgraded to websocket, we see this:

12:52:58.188 [info] CONNECTED TO Phoenix.LiveView.Socket in 23µs
  Transport: :websocket
  Serializer: Phoenix.Socket.V2.JSONSerializer
  Parameters: %{"vsn" => "2.0.0"}

12:52:58.208 [debug] MOUNT LiveWithSession
  Parameters: %{}
  Session: %{}
[examples/demo_live_with_session.exs:21: LiveWithSession.mount/3]
session #=> %{}

As you can see, the session object is blank when mount is called for the second time (for the websocket).

A potential fix is to change this line in endpoint.ex :

socket "/live", Phoenix.LiveView.Socket

to

  socket "/live", Phoenix.LiveView.Socket,
    websocket: [connect_info: [session: @session_options]],
    longpoll: [connect_info: [session: @session_options]]

This is how Phoenix's default endpoint behaves and was also suggest in this forum thread.

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A few extra things I noticed:

• README as well as example scripts are using v0.1.6 even though latest version on Hex is 0.1.7
• I tried to add a failing test for this but PhoenixPlayground.Test does not support a :plug option which is needed to use both a LiveView and a custom Plug