topic_channel.ex

defmodule Votio.TopicChannel do
  use Votio.Web, :channel
  use Guardian.Channel

  def join("topics:lobby", %{claims: claim, resource: resource}, socket) do
    {:ok, %{ message: "Joined"}, socket}
  end

  def join("topics:lobby", _, socket) do
    {:error, %{error: "authentication required"}}
  end

  def handle_in("ping", _payload, socket) do
    user = Guardian.Channel.current_resource(socket)
    push socket, "pong", %{ message: "pong", from: user.email}
    {:reply, :ok, socket}
  end

  # It is also common to receive messages from the client and
  # broadcast to everyone in the current topic (votes:lobby).
  def handle_in("shout", payload, socket) do
    broadcast socket, "shout", payload
    {:noreply, socket}
  end



  # This is invoked every time a notification is being broadcast
  # to the client. The default implementation is just to push it
  # downstream but one could filter or change the event.
  def handle_out(event, payload, socket) do
    push socket, event, payload
    {:noreply, socket}
  end

end

topic_channel_test.exs

defmodule Votio.TopicChannelTest do
  use Votio.ChannelCase

  alias Votio.TopicChannel
  import Votio.Factory

  setup do
    user = create(:user)
    {:ok, jwt, full_claims} = Guardian.encode_and_sign(user)
    {:ok, _, socket} =
    socket()
      |> subscribe_and_join(TopicChannel, "topics:lobby", %{"guardian_token" => "#{jwt}"})

    {:ok, socket: socket}
  end

  test "ping replies with status ok", %{socket: socket} do
    ref = push socket, "ping", %{}
    assert_reply ref, :ok, _
  end

  test "shout broadcasts to topics:lobby", %{socket: socket} do
    push socket, "shout", %{"hello" => "all"}
    assert_broadcast "shout", %{"hello" => "all"}
  end

  test "broadcasts are pushed to the client", %{socket: socket} do
    broadcast_from! socket, "broadcast", %{"some" => "data"}
    assert_push "broadcast", %{"some" => "data"}
  end

  test "can't push without being authenticated" do
    ref =
      socket()
    |> join(TopicChannel, "topics:lobby")
    assert_reply ref, :error, %{error: "not authenticated"}
  end

end