Move back cookie fetch to SignInForm. Role fetched and saved into a Context. Small refactorings.

src/api/PrivateRoute/PrivateRoute.tsx

@@ -6,6 +6,7 @@ import { AuthContext } from 'components/AuthUser/AuthContext';
 
 /**
  * A wrapper for <Route> that redirects to the login screen if you're not yet authenticated.
+ * Every non-public route must be wrapped with this component.
  * */
 
 type Props = {
@@ -31,17 +32,21 @@ export const PrivateRoute = ({
       setLoading(true);
       return null;
     };
-    fetch();
-  }, []);
+    /*
+    Check if user is logged in.
+    Avoiding this condition would call is\_authenticated every time
+    this component state is triggered, falling in unnecessary calls to the
+    server.
+    */
+    if (role) fetch();
+  }, [auth]);
 
   const userHasRequiredRole = requiredRoles.includes(role);
   const message = userHasRequiredRole
     ? 'Please log in to view this page'
     : 'Your role is not allowed';
 
-  return !loading ? (
-    <p>loading</p>
-  ) : (
+  return (
     <Route
       exact={false}
       path={path}
@@ -52,7 +57,7 @@ export const PrivateRoute = ({
           <Redirect
             to={{
               pathname: userHasRequiredRole
-                ? NonAuthRoutes.signIn
+                ? `auth/${NonAuthRoutes.signIn}`
                 : NonAuthRoutes.unauthorized,
               state: {
                 message,