Broadcasting an event from a controller doesn't seem to work. MyApp.Endpoint.broacast(@topic, @event, @payload)

thomasdola

Hey guys first post here!
It seems that I’m missing something because I can’t get this problem to work.

I have a simple controller when hit broadcast a welcome message to clients using Endpoint.broadcast!() function.
But event broadcast from my controller using the Endpoint does not seem to hit clients.
I even run test on the controller and they are failing…

What is confusing me is when i broadcast the same in my channel with both Channel.broadcast() and Endpoint.broadcast!() , the event hits the clients…

My Controller

defmodule RealTimeWeb.PageController do
  use RealTimeWeb, :controller

  def index(conn, _params) do
    RealTimeWeb.Endpoint.broadcast!("PAGE", "WELCOME", %{data: "Welcome to Real Time Page"})
    render(conn, "index.html")
  end
end

My Controller Test => Failed

defmodule RealTimeWeb.PageControllerTest do
  use RealTimeWeb.ConnCase

  test "GET /", %{conn: conn} do
    conn = get(conn, "/")
    assert_receive %Phoenix.Socket.Broadcast{event: "WELCOME", topic: "PAGE", payload: %{"data" => _}}
    #assert html_response(conn, 200) =~ "Welcome to Phoenix!"
  end
end

My Channel

defmodule RealTimeWeb.PageChannel do
    use RealTimeWeb, :channel

    @topic "PAGE"

    def join(@topic = topic, params, socket), do: _join(params, topic, socket)
    def join(_, _, _), do: {:error, %{reason: "unauthorized"}}

    defp _join(_params, topic, socket) do
        send(self(), {:after_join, topic})
        {:ok, socket}
    end

    def handle_info({:after_join, @topic}, socket) do
        broadcast!(socket, "WELCOME", %{data: "welcome to Real Time Channel"})
        RealTimeWeb.Endpoint.broadcast(@topic, "WELCOME", %{data: "Welcome to Real Time Channel with endpoint"})
        {:noreply, socket}
    end
end

My Channel Test => Passed

defmodule RealTimeWeb.PageChannelTest do
    use RealTimeWeb.ChannelCase
    alias RealTimeWeb.UserSocket

    setup do
        {:ok, socket} = connect(UserSocket, %{})
        {:ok, socket: socket}
    end

    test "send welcome message when join topic successfully", %{socket: socket} do
        {:ok, _, _socket} = subscribe_and_join(socket, "PAGE", %{})

        assert_broadcast "WELCOME", %{data: _}
    end

end

My Socket

defmodule RealTimeWeb.UserSocket do
  use Phoenix.Socket

  ## Channels
  channel "PAGE", RealTimeWeb.PageChannel

  def connect(_params, socket, _connect_info) do
    {:ok, socket}
  end

  def id(_socket), do: nil
end

Client side (Socket.js)


import {Socket} from "phoenix"

let socket = new Socket("/socket", {params: {token: window.userToken}})

socket.connect()

let channel = socket.channel("PAGE", {})

channel.on("WELCOME", data => console.log(data))

channel.join()
  .receive("ok", resp => { console.log("Joined successfully", resp) })
  .receive("error", resp => { console.log("Unable to join", resp) })

export default socket

I really need your help…
Thank you..

15 comments

/phoenix #channels

0 3061 15

2024-12-22 16:26:27 UTC

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hubertlepicki

Is your problem only test-related, or does it also not work when you start the app, open browser, trigger some action - in that case do you get the broadcast sent to clients?

Post #1

thomasdola

Also browser related…

Only events broadcasted from Channel Module is hitting the browser…
Not The ones being broadcasted from the Controller Module…

Post #2

rjk

just created a new phx app from scratch and copy pasted in your code. For me it worked fine (also the broadcast from the controller). I can see all messages inside the browsers dev console.
The only change on top of your code was uncommenting this line in app.js:

import socket from "./socket"

with these kind of issues I would advise to create a public github project with your whole project inside, in that way people can help you better and you talk about the exact same code (bit by bit).

Post #3

thomasdola

Dont have access at the moment ..
I ll upload the whole demo to github and link so that u can have a look at it…

Thank you..

Post #4

chrismccord

Creator of Phoenix

You need to subscribe your test process in your controller test to the topic you are broadcasting to:

RealTimeWeb.Endpoint.subscribe("PAGE")

Post #5

hubertlepicki

That’s why I asked if it’s only test-related issue. But the author claims it’s happening outside tests too.

Post #6

benwilson512

Author of Craft GraphQL APIs in Elixir with Absinthe

@hubertlepicki Sure, but the fact remains that if they want to make the test work they need to join the channel within the test.

Post #7

hubertlepicki

You, sir, make a lot of sense

Post #8

thomasdola

this is a link to the github project…
RealTime

Post #10

thomasdola

Changed the controller test to this…

defmodule RealTimeWeb.PageControllerTest do
  use RealTimeWeb.ConnCase

  setup do
    RealTimeWeb.Endpoint.subscribe("PAGE")
  end

  test "GET /", %{conn: conn} do
    conn = get(conn, "/")
    assert_receive %Phoenix.Socket.Broadcast{event: "WELCOME", topic: "PAGE", payload: %{"data" => _}}
    assert html_response(conn, 200) =~ "Welcome to Phoenix!"
  end
end

And it passed successfully.

Yet am still not receiving the “WELCOME” event in my client side…


import {Socket} from "phoenix"

let socket = new Socket("/socket", {params: {token: window.userToken}})

socket.connect()

let channel = socket.channel("PAGE", {})

channel.on("WELCOME", data => console.log(data))

channel.join()
  .receive("ok", resp => { console.log("Joined successfully", resp) })
  .receive("error", resp => { console.log("Unable to join", resp) })

export default socket

Am supposed to have 3 console log, but only 2 displaying…

These are event are hitting the client side (Being broadcasted from RealTime.PageChannel)

def handle_info({:after_join, @topic}, socket) do
        broadcast!(socket, "WELCOME", %{data: "welcome to Real Time Channel"})
        RealTimeWeb.Endpoint.broadcast(@topic, "WELCOME", %{data: "Welcome to Real Time Channel with endpoint"})
        {:noreply, socket}
end

But the following no hitting the client side (Being broadcasted from RealTime.PageController)

def index(conn, _params) do
    RealTimeWeb.Endpoint.broadcast!("PAGE", "WELCOME", %{data: "Welcome to Real Time Page"})
    render(conn, "index.html")
end

Console Log