allow guard to be specified on middleaware

app/Http/Middleware/Authenticate.php

@@ -12,11 +12,12 @@ class Authenticate
      *
      * @param  \Illuminate\Http\Request  $request
      * @param  \Closure  $next
+     * @param  string|null  $guard
      * @return mixed
      */
-    public function handle($request, Closure $next)
+    public function handle($request, Closure $next, $guard = null)
     {
-        if (Auth::guest()) {
+        if (Auth::guard($guard)->guest()) {
             if ($request->ajax()) {
                 return response('Unauthorized.', 401);
             } else {

app/Http/Middleware/RedirectIfAuthenticated.php

@@ -12,11 +12,12 @@ class RedirectIfAuthenticated
      *
      * @param  \Illuminate\Http\Request  $request
      * @param  \Closure  $next
+     * @param  string|null  $guard
      * @return mixed
      */
-    public function handle($request, Closure $next)
+    public function handle($request, Closure $next, $guard = null)
     {
-        if (Auth::check()) {
+        if (Auth::guard($guard)->check()) {
             return redirect('/');
         }