Calls to the API are checked for scope.

- Move the `Oauth2::AccessTokenValidationService` class to
  `AccessTokenValidationService`, since it is now being used for
  personal access token validation as well.

- Each API endpoint declares the scopes it accepts (if any). Currently,
  the top level API module declares the `api` scope, and the `Users` API
  module declares the `read_user` scope (for GET requests).

- Move the `find_user_by_private_token` from the API `Helpers` module to
  the `APIGuard` module, to avoid littering `Helpers` with more
  auth-related methods to support `find_user_by_private_token`

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/api/users.rb b/lib/api/users.rb
index c7db2d71017..0842c3874c5 100644
--- a/lib/api/users.rb
+++ b/lib/api/users.rb
@@ -2,7 +2,10 @@ module API
   class Users < Grape::API
     include PaginationParams
 
-    before { authenticate! }
+    before do
+      allow_access_with_scope :read_user if request.get?
+      authenticate!
+    end
 
     resource :users, requirements: { uid: /[0-9]*/, id: /[0-9]*/ } do
       helpers do