Implement access token authentication

Add whoami endpoint

lib/matrix_server_web/authenticate.ex

@@ -0,0 +1,45 @@
+defmodule MatrixServerWeb.Authenticate do
+  import Plug.Conn
+  import Phoenix.Controller, only: [json: 2]
+
+  alias MatrixServer.Account
+  alias Plug.Conn
+
+  def init(options), do: options
+
+  def call(%Conn{params: %{"access_token" => access_token}} = conn, _opts) do
+    authenticate(conn, access_token)
+  end
+
+  def call(%Conn{req_headers: headers} = conn, _opts) do
+    case List.keyfind(headers, "authorization", 0) do
+      {_, "Bearer " <> access_token} ->
+        authenticate(conn, access_token)
+
+      _ ->
+        data = %{errcode: "M_MISSING_TOKEN", error: "Access token missing."}
+
+        conn
+        |> put_status(401)
+        |> json(data)
+        |> halt()
+    end
+  end
+
+  defp authenticate(conn, access_token) do
+    case Account.get_by_access_token(access_token) do
+      %Account{devices: [device]} = account ->
+        conn
+        |> assign(:account, account)
+        |> assign(:device, device)
+
+      nil ->
+        data = %{errcode: "M_UNKNOWN_TOKEN", error: "Invalid access token."}
+
+        conn
+        |> put_status(401)
+        |> json(data)
+        |> halt()
+    end
+  end
+end

lib/matrix_server_web/controllers/account_controller.ex

@@ -1,6 +1,10 @@
 defmodule MatrixServerWeb.AccountController do
   use MatrixServerWeb, :controller
+
+  import MatrixServer, only: [get_mxid: 1]
+
   alias MatrixServer.Account
+  alias Plug.Conn
 
   def available(conn, params) do
     localpart = Map.get(params, "username", "")
@@ -21,4 +25,12 @@ defmodule MatrixServerWeb.AccountController do
     |> put_status(status)
     |> json(data)
   end
+
+  def whoami(%Conn{assigns: %{account: %Account{localpart: localpart}}} = conn, _params) do
+    data = %{user_id: get_mxid(localpart)}
+
+    conn
+    |> put_status(200)
+    |> json(data)
+  end
 end

lib/matrix_server_web/router.ex

@@ -1,12 +1,17 @@
 defmodule MatrixServerWeb.Router do
   use MatrixServerWeb, :router
 
-  pipeline :api do
+  pipeline :public do
     plug :accepts, ["json"]
   end
 
+  pipeline :authenticated do
+    plug :accepts, ["json"]
+    plug MatrixServerWeb.Authenticate
+  end
+
   scope "/_matrix", MatrixServerWeb do
-    pipe_through :api
+    pipe_through :public
 
     scope "/client/r0", as: :client do
       post "/register", AuthController, :register
@@ -16,4 +21,12 @@ defmodule MatrixServerWeb.Router do
 
     get "/client/versions", InfoController, :versions
   end
+
+  scope "/_matrix", MatrixServerWeb do
+    pipe_through :authenticated
+
+    scope "/client/r0", as: :client do
+      get "/account/whoami", AccountController, :whoami
+    end
+  end
 end