dotfiles/app/lib/prymn_web/user_auth.ex
2023-09-10 13:51:06 +03:00

207 lines
5.6 KiB
Elixir

defmodule PrymnWeb.UserAuth do
@moduledoc """
Functions and callbacks for user authentication, registration, logging out.
"""
import Plug.Conn
import Phoenix.Controller
alias Prymn.Accounts
use PrymnWeb, :verified_routes
# Make the remember me cookie valid for 60 days.
# If you want bump or reduce this value, also change
# the token expiry itself in UserToken.
@max_age 60 * 60 * 24 * 60
@remember_me_cookie "_prymn_web_user_remember_me"
@remember_me_options [sign: true, max_age: @max_age, same_site: "Lax"]
@doc """
Logs the user in.
It renews the session ID and clears the whole session
to avoid fixation attacks. See the renew_session
function to customize this behaviour.
It also sets a `:live_socket_id` key in the session,
so LiveView sessions are identified and automatically
disconnected on log out. The line can be safely removed
if you are not using LiveView.
"""
def log_in_user(conn, user, params \\ %{}) do
token = Accounts.generate_user_session_token(user)
user_return_to = get_session(conn, :user_return_to)
conn
|> renew_session()
|> put_token_in_session(token)
|> maybe_write_remember_me_cookie(token, params)
|> redirect(to: user_return_to || signed_in_path(conn))
end
defp maybe_write_remember_me_cookie(conn, token, %{"remember_me" => "true"}) do
put_resp_cookie(conn, @remember_me_cookie, token, @remember_me_options)
end
defp maybe_write_remember_me_cookie(conn, _token, _params) do
conn
end
defp renew_session(conn) do
conn
|> configure_session(renew: true)
|> clear_session()
end
@doc """
Logs the user out.
It clears all session data for safety. See renew_session.
"""
def log_out_user(conn) do
user_token = get_session(conn, :user_token)
user_token && Accounts.delete_user_session_token(user_token)
if live_socket_id = get_session(conn, :live_socket_id) do
PrymnWeb.Endpoint.broadcast(live_socket_id, "disconnect", %{})
end
conn
|> renew_session()
|> delete_resp_cookie(@remember_me_cookie)
|> redirect(to: ~p"/")
end
@doc """
Authenticates the user by looking into the session
and remember me token.
"""
def fetch_current_user(conn, _opts) do
{user_token, conn} = ensure_user_token(conn)
user = user_token && Accounts.get_user_by_session_token(user_token)
assign(conn, :current_user, user)
end
defp ensure_user_token(conn) do
if token = get_session(conn, :user_token) do
{token, conn}
else
conn = fetch_cookies(conn, signed: [@remember_me_cookie])
if token = conn.cookies[@remember_me_cookie] do
{token, put_token_in_session(conn, token)}
else
{nil, conn}
end
end
end
@doc """
Handles mounting and authenticating the current_user in LiveViews.
## `on_mount` arguments
* `:mount_current_user` - Assigns current_user
to socket assigns based on user_token, or nil if
there's no user_token or no matching user.
* `:ensure_authenticated` - Authenticates the user from the session,
and assigns the current_user to socket assigns based
on user_token.
Redirects to login page if there's no logged user.
* `:redirect_if_user_is_authenticated` - Authenticates the user from the session.
Redirects to signed_in_path if there's a logged user.
## Examples
Use the `on_mount` lifecycle macro in LiveViews to mount or authenticate
the current_user:
defmodule PrymnWeb.PageLive do
use PrymnWeb, :live_view
on_mount {PrymnWeb.UserAuth, :mount_current_user}
...
end
Or use the `live_session` of your router to invoke the on_mount callback:
live_session :authenticated, on_mount: [{PrymnWeb.UserAuth, :ensure_authenticated}] do
live "/profile", ProfileLive, :index
end
"""
def on_mount(:mount_current_user, _params, session, socket) do
{:cont, mount_current_user(socket, session)}
end
def on_mount(:ensure_authenticated, _params, session, socket) do
socket = mount_current_user(socket, session)
if socket.assigns.current_user do
{:cont, socket}
else
{:halt, Phoenix.LiveView.redirect(socket, to: ~p"/auth/log_in")}
end
end
def on_mount(:redirect_if_user_is_authenticated, _params, session, socket) do
socket = mount_current_user(socket, session)
if socket.assigns.current_user do
{:halt, Phoenix.LiveView.redirect(socket, to: signed_in_path(socket))}
else
{:cont, socket}
end
end
defp mount_current_user(socket, session) do
Phoenix.Component.assign_new(socket, :current_user, fn ->
if user_token = session["user_token"] do
Accounts.get_user_by_session_token(user_token)
end
end)
end
@doc """
Used for routes that require the user to not be authenticated.
"""
def redirect_if_user_is_authenticated(conn, _opts) do
if conn.assigns[:current_user] do
conn
|> redirect(to: signed_in_path(conn))
|> halt()
else
conn
end
end
@doc """
Used for routes that require the user to be authenticated.
"""
def require_authenticated_user(conn, _opts) do
if conn.assigns[:current_user] do
conn
else
conn
|> maybe_store_return_to()
|> redirect(to: ~p"/auth/log_in")
|> halt()
end
end
defp put_token_in_session(conn, token) do
conn
|> put_session(:user_token, token)
|> put_session(:live_socket_id, "users_sessions:#{Base.url_encode64(token)}")
end
defp maybe_store_return_to(%{method: "GET"} = conn) do
put_session(conn, :user_return_to, current_path(conn))
end
defp maybe_store_return_to(conn), do: conn
defp signed_in_path(_conn), do: ~p"/"
end