Maintaining the current logged in user.

How do we maintain the current user, like in liveviews we fetch it from the session.

60 Replies

You can use the load_from_session plug in your router, which should be documented and then you can use the live session For instance, we do this in ash_hq around our liveviews

    ash_authentication_live_session :main,
      on_mount: [
        {AshHqWeb.LiveUserAuth, :live_user_optional},
        {AshHqWeb.InitAssigns, :default}
      ],
      session: {AshAuthentication.Phoenix.LiveSession, :generate_session, []},
      root_layout: {AshHqWeb.LayoutView, :root} do
  ...
end

    ash_authentication_live_session :main,
      on_mount: [
        {AshHqWeb.LiveUserAuth, :live_user_optional},
        {AshHqWeb.InitAssigns, :default}
      ],
      session: {AshAuthentication.Phoenix.LiveSession, :generate_session, []},
      root_layout: {AshHqWeb.LayoutView, :root} do
  ...
end

talha-azeemOP•3y ago

so i will add the on_mount one? in my liveviews?

ZachDaniel•3y ago

Have you done this kind of thing with liveview before? It might be worth reading their documentation on this stuff too The load_from_session plug is documented in the getting started guide for ash_authentication_phoenix, and will make a current_user assign available the on_mount is something you write yourself but just adding ash_authentication_live_session will set the current_user assign So the {AshHqWeb.LiveUserAuth, :live_user_optional} is something I wrote for AshHq specifically

talha-azeemOP•3y ago

yes i have but at that time i had to write a custom live helper to fetch the current user from session and assign it to the socket and called that function in every mount of liveview.

ZachDaniel•3y ago

Ah, yeah so thats been updated and now you can use on_mount hooks like the one I mentioned so ash_authentication_live_session will set current_user assign, and then you can add an on_mount hook to do things like require that the user is there for certain routes i.e

 ash_authentication_live_session :main,
      on_mount: [
        {MyApp.LiveUserAuth, :live_user_optional},
      ] do
  live "/unsecured_route", ...
end

 ash_authentication_live_session :main,
      on_mount: [
        {MyApp.LiveUserAuth, :live_user_required},
      ] do
  live "/secured_route", ...
end

 ash_authentication_live_session :main,
      on_mount: [
        {MyApp.LiveUserAuth, :live_user_optional},
      ] do
  live "/unsecured_route", ...
end

 ash_authentication_live_session :main,
      on_mount: [
        {MyApp.LiveUserAuth, :live_user_required},
      ] do
  live "/secured_route", ...
end

This is what it looks like in AshHq

defmodule AshHqWeb.LiveUserAuth do
  @moduledoc """
  Helpers for authenticating users in liveviews
  """

  import Phoenix.Component
  use AshHqWeb, :verified_routes

  def on_mount(:live_user_optional, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, socket}
    else
      {:cont, assign(socket, :current_user, nil)}
    end
  end

  def on_mount(:live_user_required, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, socket}
    else
      {:halt, Phoenix.LiveView.redirect(socket, to: ~p"/sign-in")}
    end
  end
end

defmodule AshHqWeb.LiveUserAuth do
  @moduledoc """
  Helpers for authenticating users in liveviews
  """

  import Phoenix.Component
  use AshHqWeb, :verified_routes

  def on_mount(:live_user_optional, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, socket}
    else
      {:cont, assign(socket, :current_user, nil)}
    end
  end

  def on_mount(:live_user_required, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, socket}
    else
      {:halt, Phoenix.LiveView.redirect(socket, to: ~p"/sign-in")}
    end
  end
end

That makes sure that the assigns I want are always there (current_user) and also handles requiring a user for some routes

talha-azeemOP•3y ago

What i understood from on_mount live user required one is making sure that the current user is present.

ZachDaniel•3y ago

Correct This example is from the getting started guide for ash authentication phoenix:

defmodule MyAppWeb.Router do
  use MyAppWeb, :router
  use AshAuthentication.Phoenix.Router

  pipeline :browser do
    # ...
    plug(:load_from_session) # <- this line will load the user from the session
  end

  pipeline :api do
    # ...
    plug(:load_from_bearer)
  end

  # This stuff is the authentication routes
  scope "/", MyAppWeb do
    pipe_through :browser
    sign_in_route
    sign_out_route AuthController
    auth_routes_for MyApp.Accounts.User, to: AuthController
  end

  scope "/", MyAppWeb do
    ash_authentication_session <opts> do 
    #<- this sets the `current_user` assign if the user is logged in, for any liveviews inside
       live ....
    end
  end
end

defmodule MyAppWeb.Router do
  use MyAppWeb, :router
  use AshAuthentication.Phoenix.Router

  pipeline :browser do
    # ...
    plug(:load_from_session) # <- this line will load the user from the session
  end

  pipeline :api do
    # ...
    plug(:load_from_bearer)
  end

  # This stuff is the authentication routes
  scope "/", MyAppWeb do
    pipe_through :browser
    sign_in_route
    sign_out_route AuthController
    auth_routes_for MyApp.Accounts.User, to: AuthController
  end

  scope "/", MyAppWeb do
    ash_authentication_session <opts> do 
    #<- this sets the `current_user` assign if the user is logged in, for any liveviews inside
       live ....
    end
  end
end

talha-azeemOP•3y ago

Now i understood it. I am sorry. I couldn't find it in the docs. 😅

ZachDaniel•3y ago

no problem 👍

talha-azeemOP•3y ago

If i want the relationships of user to be loaded then?

ZachDaniel•3y ago

Put that in your on_mount hook and use Accounts.load(user, [:relationships, ...])

talha-azeemOP•3y ago

so that i have to do through plug.

ZachDaniel•3y ago

You can do it in the on_mount hook like I showed above, just add logic to load relationships

  def on_mount(:live_user_optional, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, assign(socket, :current_user, MyApp.Accounts.load!(socket.assigns.current_user, [:foo, :bar])}
    else
      {:cont, assign(socket, :current_user, nil)}
    end
  end

  def on_mount(:live_user_required, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, assign(socket, :current_user, MyApp.Accounts.load!(socket.assigns.current_user, [:foo, :bar])}
    else
      {:halt, Phoenix.LiveView.redirect(socket, to: ~p"/sign-in")}
    end
  end

  def on_mount(:live_user_optional, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, assign(socket, :current_user, MyApp.Accounts.load!(socket.assigns.current_user, [:foo, :bar])}
    else
      {:cont, assign(socket, :current_user, nil)}
    end
  end

  def on_mount(:live_user_required, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, assign(socket, :current_user, MyApp.Accounts.load!(socket.assigns.current_user, [:foo, :bar])}
    else
      {:halt, Phoenix.LiveView.redirect(socket, to: ~p"/sign-in")}
    end
  end

Like that

talha-azeemOP•3y ago

yeah i got it 😄 or i can add another on_mount just to load the relations

ZachDaniel•3y ago

yep! That would be a good way to do it

talha-azeemOP•3y ago

in list we provide the relations that we need to load, right? is it different from the Ash.Query.load?

ZachDaniel•3y ago

They are exactly the same 👍

talha-azeemOP•3y ago

MyApp.Accounts.load!(socket.assigns, :current_user, [:teams]) if i do this it gives me error

ZachDaniel•3y ago

That isn't how that works the first argument to load! is the ash record and the second argument is the stuff you want to load MyApp.Accounts.load!(socket.assigns.current_user, [:teams])

talha-azeemOP•3y ago

oh, i picked the one you wrote above in the on_mount hook

ZachDaniel•3y ago

Oh sorry 🙂

talha-azeemOP•3y ago

no, don't be.

ZachDaniel•3y ago

I've fixed the example

talha-azeemOP•3y ago

its just i am new 😅

ZachDaniel•3y ago

Doesn't help when I give you bad code samples 😆

talha-azeemOP•3y ago

it still gives me the error * No read action exists for Dummy.Accounts.Team when: loading relationship teams I have this defined in Team resource:

actions do
    defaults [:create, :read, :update, :destroy]
  end

actions do
    defaults [:create, :read, :update, :destroy]
  end

ZachDaniel•3y ago

Can I see the whole resource?

talha-azeemOP•3y ago

defmodule Dummy.Accounts.Team do
  use Ash.Resource, data_layer: AshPostgres.DataLayer

  postgres do
    repo(Dummy.Repo)
    table("teams")
  end

  actions do
    defaults [:create, :read, :update, :destroy]
  end

  attributes do
    uuid_primary_key :id
    attribute :name, :string
    timestamps()
  end

  relationships do
    many_to_many :users, Dummy.Accounts.User do
      through Dummy.Accounts.TeamJoinedUser
      source_attribute_on_join_resource :team_id
      destination_attribute_on_join_resource :user_id
    end
  end
end

defmodule Dummy.Accounts.Team do
  use Ash.Resource, data_layer: AshPostgres.DataLayer

  postgres do
    repo(Dummy.Repo)
    table("teams")
  end

  actions do
    defaults [:create, :read, :update, :destroy]
  end

  attributes do
    uuid_primary_key :id
    attribute :name, :string
    timestamps()
  end

  relationships do
    many_to_many :users, Dummy.Accounts.User do
      through Dummy.Accounts.TeamJoinedUser
      source_attribute_on_join_resource :team_id
      destination_attribute_on_join_resource :user_id
    end
  end
end

ZachDaniel•3y ago

You sure you've saved it and recompiled and everything? That looks right to me

talha-azeemOP•3y ago

yes, i have auto save enabled

ZachDaniel•3y ago

and you restarted your server? Sorry, just being thorough because that looks right to me

talha-azeemOP•3y ago

Yup same error

ZachDaniel•3y ago

Can I see your code where you're loading it?

talha-azeemOP•3y ago

yes gimme a sec

def on_mount(:load_assocs_current_user, _params, _session, socket) do
    {:cont, assign(socket, :current_user, Dummy.Accounts.load!(socket.assigns.current_user, [:teams]))}
  end

def on_mount(:load_assocs_current_user, _params, _session, socket) do
    {:cont, assign(socket, :current_user, Dummy.Accounts.load!(socket.assigns.current_user, [:teams]))}
  end

added this is auth plug

ZachDaniel•3y ago

Ah That is fine, but I think the issue is probably on your join resource Dummy.Accounts.TeamJoinedUser also needs defaults [:read, :create, :update, :destroy]

talha-azeemOP•3y ago

yeah that was the issue Am i missing something here? no function clause matching in Plug.Conn.assign/3 It is giving me this error.

ZachDaniel•3y ago

That shouldn't be calling Plug.Conn.assign it should be from Phoenix.Component I believe did you try to put the on_mount in a plug?

talha-azeemOP•3y ago

nope

ZachDaniel•3y ago

can I see the whole module

talha-azeemOP•3y ago

defmodule DummyWeb.User.TeamLive.Index do
  use DummyWeb, :live_view

  alias Dummy.Accounts

  on_mount {Dummy.AuthPlug, :load_assocs_current_user}

  @impl true
  def mount(_params, _session, socket) do
    {:ok, socket}
  end

  @impl true
  def handle_event("show-team-details", %{"id" => team_id}, socket) do
    # team = Accounts.get_team!(id)
    # {:noreply, socket}
    user_id = socket.assigns.current_user.id
    {:noreply, redirect(socket, to: "<path>")}
  end

  @impl true
  def handle_params(params, _uri, socket) do
    {:noreply, apply_action(socket, socket.assigns.live_action, params)}
  end

  def apply_action(socket, :index, _params) do
    assign(socket, page_title: "All Teams")
  end

  # def apply_action(socket, :team_details, _params) do
  #   assign(socket, page_title: "Team Details")
  # end

  def apply_action(socket, :new, _params) do
    # form =
    #   Accounts.Team
    #   |> AshPhoenix.Form.for_create(:create,
    #     api: Team,
    #     forms: [auto?: true]
    #   )
    #   |> IO.inspect(label: "here in team form => ")

    socket
    |> assign(page_title: "New Team")
    # |> assign(form: form, page_title: "New Team")
  end
end

defmodule DummyWeb.User.TeamLive.Index do
  use DummyWeb, :live_view

  alias Dummy.Accounts

  on_mount {Dummy.AuthPlug, :load_assocs_current_user}

  @impl true
  def mount(_params, _session, socket) do
    {:ok, socket}
  end

  @impl true
  def handle_event("show-team-details", %{"id" => team_id}, socket) do
    # team = Accounts.get_team!(id)
    # {:noreply, socket}
    user_id = socket.assigns.current_user.id
    {:noreply, redirect(socket, to: "<path>")}
  end

  @impl true
  def handle_params(params, _uri, socket) do
    {:noreply, apply_action(socket, socket.assigns.live_action, params)}
  end

  def apply_action(socket, :index, _params) do
    assign(socket, page_title: "All Teams")
  end

  # def apply_action(socket, :team_details, _params) do
  #   assign(socket, page_title: "Team Details")
  # end

  def apply_action(socket, :new, _params) do
    # form =
    #   Accounts.Team
    #   |> AshPhoenix.Form.for_create(:create,
    #     api: Team,
    #     forms: [auto?: true]
    #   )
    #   |> IO.inspect(label: "here in team form => ")

    socket
    |> assign(page_title: "New Team")
    # |> assign(form: form, page_title: "New Team")
  end
end

ZachDaniel•3y ago

on_mount {Dummy.AuthPlug, :load_assocs_current_user} I didn't even know you could do this

talha-azeemOP•3y ago

really?

ZachDaniel•3y ago

Yeah, I only ever did them in the live_session

talha-azeemOP•3y ago

I got to know about them recently myself tho.

ZachDaniel•3y ago

anyway, can I see AuthPlug? Because it looks like you did something like import Plug and thats not what you want to do

talha-azeemOP•3y ago

when i implemented mix phx.gen.auth it gave an example there for this.

defmodule DummyWeb.AuthPlug do
  use AshAuthentication.Plug, otp_app: :dummy_app
  use DummyWeb, :verified_routes

  def handle_success(conn, _activity, user, token) do
    if is_api_request?(conn) do
      conn
      |> send_resp(200, Jason.encode!(%{
        authentication: %{
          success: true,
          token: token
        }
      }))
    else
      conn
      |> store_in_session(user)
      |> send_resp(200, EEx.eval_string("""
      <h2>Welcome back <%= @user.email %></h2>
      """, user: user))
    end
  end

  def handle_failure(conn, _activity, _reason) do
    if is_api_request?(conn) do
      conn
      |> send_resp(401, Jason.encode!(%{
        authentication: %{
          success: false
        }
      }))
    else
      conn
      |> send_resp(401, "<h2>Incorrect email or password</h2>")
    end
  end

  defp is_api_request?(conn), do: "application/json" in get_req_header(conn, "accept")

  def on_mount(:live_user_required, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, socket}
    else
      {:halt, Phoenix.LiveView.redirect(socket, to: ~p"/sign-in")}
    end
  end

  def on_mount(:load_assocs_current_user, _params, _session, socket) do
    {:cont, assign(socket, :current_user, Dummy.Accounts.load!(socket.assigns.current_user, [:teams]))}
  end
end

defmodule DummyWeb.AuthPlug do
  use AshAuthentication.Plug, otp_app: :dummy_app
  use DummyWeb, :verified_routes

  def handle_success(conn, _activity, user, token) do
    if is_api_request?(conn) do
      conn
      |> send_resp(200, Jason.encode!(%{
        authentication: %{
          success: true,
          token: token
        }
      }))
    else
      conn
      |> store_in_session(user)
      |> send_resp(200, EEx.eval_string("""
      <h2>Welcome back <%= @user.email %></h2>
      """, user: user))
    end
  end

  def handle_failure(conn, _activity, _reason) do
    if is_api_request?(conn) do
      conn
      |> send_resp(401, Jason.encode!(%{
        authentication: %{
          success: false
        }
      }))
    else
      conn
      |> send_resp(401, "<h2>Incorrect email or password</h2>")
    end
  end

  defp is_api_request?(conn), do: "application/json" in get_req_header(conn, "accept")

  def on_mount(:live_user_required, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, socket}
    else
      {:halt, Phoenix.LiveView.redirect(socket, to: ~p"/sign-in")}
    end
  end

  def on_mount(:load_assocs_current_user, _params, _session, socket) do
    {:cont, assign(socket, :current_user, Dummy.Accounts.load!(socket.assigns.current_user, [:teams]))}
  end
end

ZachDaniel•3y ago

Yeah, so because you put that in your AuthPlug, when you say assign its calling the imported Plug.Conn.assign But there is a different assign that you are supposed to use with liveview sockets Phoenix.Component.assign For example, the one we use in ash_hq

defmodule AshHqWeb.LiveUserAuth do
  @moduledoc """
  Helpers for authenticating users in liveviews
  """

  import Phoenix.Component
  use AshHqWeb, :verified_routes

  def on_mount(:live_user_optional, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, socket}
    else
      {:cont, assign(socket, :current_user, nil)}
    end
  end

  def on_mount(:live_user_required, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, socket}
    else
      {:halt, Phoenix.LiveView.redirect(socket, to: ~p"/sign-in")}
    end
  end
end

defmodule AshHqWeb.LiveUserAuth do
  @moduledoc """
  Helpers for authenticating users in liveviews
  """

  import Phoenix.Component
  use AshHqWeb, :verified_routes

  def on_mount(:live_user_optional, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, socket}
    else
      {:cont, assign(socket, :current_user, nil)}
    end
  end

  def on_mount(:live_user_required, _params, _session, socket) do
    if socket.assigns[:current_user] do
      {:cont, socket}
    else
      {:halt, Phoenix.LiveView.redirect(socket, to: ~p"/sign-in")}
    end
  end
end