Use system paths for appearance logos

When object storage is enabled, the logos used to customize a GitLab
appearance causes the time-limited URLs to be used. We fix this
by forcing all of these URLs to use the /uploads/-/system prefix
so that they will always be proxied through GitLab.

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/6778

2 files changed, 34 insertions, 0 deletions

diff --git a/spec/factories/appearances.rb b/spec/factories/appearances.rb
index 18c7453bd1b..dd5129229d4 100644
--- a/spec/factories/appearances.rb
+++ b/spec/factories/appearances.rb
@@ -15,6 +15,10 @@ FactoryBot.define do
     header_logo { fixture_file_upload('spec/fixtures/dk.png') }
   end
 
+  trait :with_favicon do
+    favicon { fixture_file_upload('spec/fixtures/dk.png') }
+  end
+
   trait :with_logos do
     with_logo
     with_header_logo
diff --git a/spec/models/appearance_spec.rb b/spec/models/appearance_spec.rb
index 35415030154..ec2e7d672f0 100644
--- a/spec/models/appearance_spec.rb
+++ b/spec/models/appearance_spec.rb
@@ -26,4 +26,34 @@ describe Appearance do
       let(:uploader_class) { AttachmentUploader }
     end
   end
+
+  shared_examples 'logo paths' do |logo_type|
+    let(:appearance) { create(:appearance, "with_#{logo_type}".to_sym) }
+    let(:filename) { 'dk.png' }
+    let(:expected_path) { "/uploads/-/system/appearance/#{logo_type}/#{appearance.id}/#{filename}" }
+
+    it 'returns nil when there is no upload' do
+      expect(subject.send("#{logo_type}_path")).to be_nil
+    end
+
+    it 'returns a local path using the system route' do
+      expect(appearance.send("#{logo_type}_path")).to eq(expected_path)
+    end
+
+    describe 'with asset host configured' do
+      let(:asset_host) { 'https://gitlab-assets.example.com' }
+
+      before do
+        allow(ActionController::Base).to receive(:asset_host) { asset_host }
+      end
+
+      it 'returns a full URL with the system path' do
+        expect(appearance.send("#{logo_type}_path")).to eq("#{asset_host}#{expected_path}")
+      end
+    end
+  end
+
+  %i(logo header_logo favicon).each do |logo_type|
+    it_behaves_like 'logo paths', logo_type
+  end
 end