Handle client side flow for google auth.

Author: Rohan Pujari

lib/ueberauth/strategy/google.ex

@@ -31,14 +31,20 @@ defmodule Ueberauth.Strategy.Google do
   @doc """
   Handles the callback from Google.
   """
-  def handle_callback!(%Plug.Conn{params: %{"code" => code}} = conn) do
-    opts = [redirect_uri: callback_url(conn)]
-    token = Ueberauth.Strategy.Google.OAuth.get_token!([code: code], opts)
-
-    if token.access_token == nil do
-      set_errors!(conn, [error(token.other_params["error"], token.other_params["error_description"])])
-    else
-      fetch_user(conn, token)
+  def handle_callback!(%Plug.Conn{params: params} = conn) do
+    case params do
+      %{"code" => code} ->
+        opts = [redirect_uri: callback_url(conn)]
+        token = Ueberauth.Strategy.Google.OAuth.get_token!([code: code], opts)
+        if token.access_token == nil do
+          set_errors!(conn, [error(token.other_params["error"], token.other_params["error_description"])])
+        else
+          fetch_user(conn, token)
+        end
+      %{"token" => token} ->
+        fetch_user(conn, OAuth2.AccessToken.new(token))
+      _ ->
+        set_errors!(conn, [error("missing_code_or_token", "No code or token received")])
     end
   end
 
@@ -124,7 +130,7 @@ defmodule Ueberauth.Strategy.Google do
     resp = Ueberauth.Strategy.Google.OAuth.get(token, path)
 
     case resp do
-      {:ok, %OAuth2.Response{status_code: 401, body: _body}} ->
+      {:error, %OAuth2.Response{status_code: 401, body: _body}} ->
         set_errors!(conn, [error("token", "unauthorized")])
       {:ok, %OAuth2.Response{status_code: status_code, body: user}} when status_code in 200..399 ->
         put_private(conn, :google_user, user)