Feature: Allow token introspection without read scope (#27142)

app/controllers/api/v1/apps/credentials_controller.rb

@@ -1,9 +1,9 @@
 # frozen_string_literal: true
 
 class Api::V1::Apps::CredentialsController < Api::BaseController
-  before_action -> { doorkeeper_authorize! :read }
-
   def show
-    render json: doorkeeper_token.application, serializer: REST::ApplicationSerializer, fields: %i(name website vapid_key)
+    return doorkeeper_render_error unless valid_doorkeeper_token?
+
+    render json: doorkeeper_token.application, serializer: REST::ApplicationSerializer, fields: %i(name website vapid_key client_id scopes)
   end
 end

app/serializers/rest/application_serializer.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class REST::ApplicationSerializer < ActiveModel::Serializer
-  attributes :id, :name, :website, :redirect_uri,
+  attributes :id, :name, :website, :scopes, :redirect_uri,
              :client_id, :client_secret, :vapid_key
 
   def id

spec/requests/api/v1/apps/credentials_spec.rb

@@ -9,7 +9,8 @@ describe 'Credentials' do
     end
 
     context 'with an oauth token' do
-      let(:token)   { Fabricate(:accessible_access_token, scopes: 'read', application: Fabricate(:application)) }
+      let(:application) { Fabricate(:application, scopes: 'read') }
+      let(:token)   { Fabricate(:accessible_access_token, application: application) }
       let(:headers) { { 'Authorization' => "Bearer #{token.token}" } }
 
       it 'returns the app information correctly', :aggregate_failures do
@@ -21,7 +22,35 @@ describe 'Credentials' do
           a_hash_including(
             name: token.application.name,
             website: token.application.website,
-            vapid_key: Rails.configuration.x.vapid_public_key
+            vapid_key: Rails.configuration.x.vapid_public_key,
+            scopes: token.application.scopes.map(&:to_s),
+            client_id: token.application.uid
+          )
+        )
+      end
+    end
+
+    context 'with a non-read scoped oauth token' do
+      let(:application) { Fabricate(:application, scopes: 'admin:write') }
+      let(:token)   { Fabricate(:accessible_access_token, application: application) }
+      let(:headers) { { 'Authorization' => "Bearer #{token.token}" } }
+
+      it 'returns http success' do
+        subject
+
+        expect(response).to have_http_status(200)
+      end
+
+      it 'returns the app information correctly' do
+        subject
+
+        expect(body_as_json).to match(
+          a_hash_including(
+            name: token.application.name,
+            website: token.application.website,
+            vapid_key: Rails.configuration.x.vapid_public_key,
+            scopes: token.application.scopes.map(&:to_s),
+            client_id: token.application.uid
           )
         )
       end
@@ -36,5 +65,49 @@ describe 'Credentials' do
         expect(response).to have_http_status(401)
       end
     end
+
+    context 'with a revoked oauth token' do
+      let(:application) { Fabricate(:application, scopes: 'read') }
+      let(:token)   { Fabricate(:accessible_access_token, application: application, revoked_at: DateTime.now.utc) }
+      let(:headers) { { 'Authorization' => "Bearer #{token.token}" } }
+
+      it 'returns http authorization error' do
+        subject
+
+        expect(response).to have_http_status(401)
+      end
+
+      it 'returns the error in the json response' do
+        subject
+
+        expect(body_as_json).to match(
+          a_hash_including(
+            error: 'The access token was revoked'
+          )
+        )
+      end
+    end
+
+    context 'with an invalid oauth token' do
+      let(:application) { Fabricate(:application, scopes: 'read') }
+      let(:token)   { Fabricate(:accessible_access_token, application: application) }
+      let(:headers) { { 'Authorization' => "Bearer #{token.token}-invalid" } }
+
+      it 'returns http authorization error' do
+        subject
+
+        expect(response).to have_http_status(401)
+      end
+
+      it 'returns the error in the json response' do
+        subject
+
+        expect(body_as_json).to match(
+          a_hash_including(
+            error: 'The access token is invalid'
+          )
+        )
+      end
+    end
   end
 end