diff --git a/app/controllers/concerns/project_unauthorized.rb b/app/controllers/concerns/project_unauthorized.rb
index d42363b8b175c1899c208c228bca93fcb9055779..7238840440f44022f42d378ed15368f2e43aff71 100644
--- a/app/controllers/concerns/project_unauthorized.rb
+++ b/app/controllers/concerns/project_unauthorized.rb
@@ -1,10 +1,12 @@
 # frozen_string_literal: true
 
 module ProjectUnauthorized
-  def project_unauthorized_proc
-    lambda do |project|
-      if project
-        label = project.external_authorization_classification_label
+  module ControllerActions
+    def self.on_routable_not_found
+      lambda do |routable|
+        return unless routable.is_a?(Project)
+
+        label = routable.external_authorization_classification_label
         rejection_reason = nil
 
         unless ::Gitlab::ExternalAuthorization.access_allowed?(current_user, label)
@@ -12,9 +14,7 @@ module ProjectUnauthorized
           rejection_reason ||= _('External authorization denied access to this project')
         end
 
-        if rejection_reason
-          access_denied!(rejection_reason)
-        end
+        access_denied!(rejection_reason) if rejection_reason
       end
     end
   end
diff --git a/app/controllers/concerns/routable_actions.rb b/app/controllers/concerns/routable_actions.rb
index 5624eb3aa45cb060c664909efb6912c1bfd873f9..ff9b0332c978f7f9f66fe17937484f394d91593d 100644
--- a/app/controllers/concerns/routable_actions.rb
+++ b/app/controllers/concerns/routable_actions.rb
@@ -3,15 +3,13 @@
 module RoutableActions
   extend ActiveSupport::Concern
 
-  def find_routable!(routable_klass, requested_full_path, extra_authorization_proc: nil, not_found_or_authorized_proc: nil)
+  def find_routable!(routable_klass, requested_full_path, extra_authorization_proc: nil)
     routable = routable_klass.find_by_full_path(requested_full_path, follow_redirects: request.get?)
     if routable_authorized?(routable, extra_authorization_proc)
       ensure_canonical_path(routable, requested_full_path)
       routable
     else
-      if not_found_or_authorized_proc
-        not_found_or_authorized_proc.call(routable)
-      end
+      perform_not_found_actions(routable, not_found_actions)
 
       route_not_found unless performed?
 
@@ -19,6 +17,18 @@ module RoutableActions
     end
   end
 
+  def not_found_actions
+    [ProjectUnauthorized::ControllerActions.on_routable_not_found]
+  end
+
+  def perform_not_found_actions(routable, actions)
+    actions.each do |action|
+      break if performed?
+
+      instance_exec(routable, &action)
+    end
+  end
+
   def routable_authorized?(routable, extra_authorization_proc)
     return false unless routable
 
diff --git a/app/controllers/projects/application_controller.rb b/app/controllers/projects/application_controller.rb
index 781eac7f080281b7f544c6ba6a0990c8dc13cf93..80e4f54bbf45b53a7f6238b15379d9f2984a7b60 100644
--- a/app/controllers/projects/application_controller.rb
+++ b/app/controllers/projects/application_controller.rb
@@ -3,7 +3,6 @@
 class Projects::ApplicationController < ApplicationController
   include CookiesHelper
   include RoutableActions
-  include ProjectUnauthorized
   include ChecksCollaboration
 
   skip_before_action :authenticate_user!
@@ -22,7 +21,7 @@ class Projects::ApplicationController < ApplicationController
     path = File.join(params[:namespace_id], params[:project_id] || params[:id])
     auth_proc = ->(project) { !project.pending_delete? }
 
-    @project = find_routable!(Project, path, extra_authorization_proc: auth_proc, not_found_or_authorized_proc: project_unauthorized_proc)
+    @project = find_routable!(Project, path, extra_authorization_proc: auth_proc)
   end
 
   def build_canonical_path(project)
diff --git a/app/controllers/projects/clusters/applications_controller.rb b/app/controllers/projects/clusters/applications_controller.rb
index c7b6218d0073300f20681c99578609a73070037f..2a04b007304192612fe4b29427a766c04f126604 100644
--- a/app/controllers/projects/clusters/applications_controller.rb
+++ b/app/controllers/projects/clusters/applications_controller.rb
@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 class Projects::Clusters::ApplicationsController < Clusters::ApplicationsController
-  include ProjectUnauthorized
-
   prepend_before_action :project
 
   private
@@ -12,6 +10,6 @@ class Projects::Clusters::ApplicationsController < Clusters::ApplicationsControl
   end
 
   def project
-    @project ||= find_routable!(Project, File.join(params[:namespace_id], params[:project_id]), not_found_or_authorized_proc: project_unauthorized_proc)
+    @project ||= find_routable!(Project, File.join(params[:namespace_id], params[:project_id]))
   end
 end
diff --git a/app/controllers/projects/clusters_controller.rb b/app/controllers/projects/clusters_controller.rb
index feda6deeaa6c36fed3ee3debfcc0d7aa92175ec9..cb02581da371eb0d8cc5a61f63d2ecad9bfa6a1e 100644
--- a/app/controllers/projects/clusters_controller.rb
+++ b/app/controllers/projects/clusters_controller.rb
@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 class Projects::ClustersController < Clusters::ClustersController
-  include ProjectUnauthorized
-
   prepend_before_action :project
   before_action :repository
 
@@ -15,7 +13,7 @@ class Projects::ClustersController < Clusters::ClustersController
   end
 
   def project
-    @project ||= find_routable!(Project, File.join(params[:namespace_id], params[:project_id]), not_found_or_authorized_proc: project_unauthorized_proc)
+    @project ||= find_routable!(Project, File.join(params[:namespace_id], params[:project_id]))
   end
 
   def repository
diff --git a/app/controllers/projects/serverless/functions_controller.rb b/app/controllers/projects/serverless/functions_controller.rb
index 8c3d141c888c17e52c3e9e91c6ad899e614f7a15..79030da64d34834a13534cae03b34e5a0825357a 100644
--- a/app/controllers/projects/serverless/functions_controller.rb
+++ b/app/controllers/projects/serverless/functions_controller.rb
@@ -3,8 +3,6 @@
 module Projects
   module Serverless
     class FunctionsController < Projects::ApplicationController
-      include ProjectUnauthorized
-
       before_action :authorize_read_cluster!
 
       def index
diff --git a/spec/controllers/concerns/project_unauthorized_spec.rb b/spec/controllers/concerns/project_unauthorized_spec.rb
index 57ac00cf4ddb1c056725e7a4e23c6b2aebee1635..5834b1ef37fd6558828e10ad2f5aa1afbf04cecb 100644
--- a/spec/controllers/concerns/project_unauthorized_spec.rb
+++ b/spec/controllers/concerns/project_unauthorized_spec.rb
@@ -12,7 +12,7 @@ describe ProjectUnauthorized do
 
   render_views
 
-  describe '#project_unauthorized_proc' do
+  describe '.on_routable_not_found' do
     controller(::Projects::ApplicationController) do
       def show
         head :ok
diff --git a/spec/controllers/concerns/routable_actions_spec.rb b/spec/controllers/concerns/routable_actions_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..59d48c68b9cc9e0788d9aca1b25d6dbe5851cb85
--- /dev/null
+++ b/spec/controllers/concerns/routable_actions_spec.rb
@@ -0,0 +1,156 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe RoutableActions do
+  controller(::ApplicationController) do
+    include RoutableActions # rubocop:disable RSpec/DescribedClass
+
+    before_action :routable
+
+    def routable
+      @klass = params[:type].constantize
+      @routable = find_routable!(params[:type].constantize, params[:id])
+    end
+
+    def show
+      head :ok
+    end
+  end
+
+  def get_routable(routable)
+    get :show, params: { id: routable.full_path, type: routable.class }
+  end
+
+  describe '#find_routable!' do
+    context 'when signed in' do
+      let(:user) { create(:user) }
+
+      before do
+        sign_in(user)
+      end
+
+      context 'with a project' do
+        let(:routable) { create(:project) }
+
+        context 'when authorized' do
+          before do
+            routable.add_guest(user)
+          end
+
+          it 'returns the project' do
+            get_routable(routable)
+
+            expect(assigns[:routable]).to be_a(Project)
+          end
+
+          it 'allows access' do
+            get_routable(routable)
+
+            expect(response).to have_gitlab_http_status(200)
+          end
+        end
+
+        it 'prevents access when not authorized' do
+          get_routable(routable)
+
+          expect(response).to have_gitlab_http_status(404)
+        end
+      end
+
+      context 'with a group' do
+        let(:routable) { create(:group, :private) }
+
+        context 'when authorized' do
+          before do
+            routable.add_guest(user)
+          end
+
+          it 'returns the group' do
+            get_routable(routable)
+
+            expect(assigns[:routable]).to be_a(Group)
+          end
+
+          it 'allows access' do
+            get_routable(routable)
+
+            expect(response).to have_gitlab_http_status(200)
+          end
+        end
+
+        it 'prevents access when not authorized' do
+          get_routable(routable)
+
+          expect(response).to have_gitlab_http_status(404)
+        end
+      end
+
+      context 'with a user' do
+        let(:routable) { user }
+
+        it 'allows access when authorized' do
+          get_routable(routable)
+
+          expect(response).to have_gitlab_http_status(200)
+        end
+
+        it 'prevents access when unauthorized' do
+          allow(subject).to receive(:can?).and_return(false)
+
+          get_routable(user)
+
+          expect(response).to have_gitlab_http_status(404)
+        end
+      end
+    end
+
+    context 'when not signed in' do
+      it 'redirects to sign in for private resouces' do
+        routable = create(:project, :private)
+
+        get_routable(routable)
+
+        expect(response).to have_gitlab_http_status(302)
+        expect(response.location).to end_with('/users/sign_in')
+      end
+    end
+  end
+
+  describe '#perform_not_found_actions' do
+    let(:routable) { create(:project) }
+
+    before do
+      sign_in(create(:user))
+    end
+
+    it 'performs multiple checks' do
+      last_check_called = false
+      checks = [proc {}, proc { last_check_called = true }]
+      allow(subject).to receive(:not_found_actions).and_return(checks)
+
+      get_routable(routable)
+
+      expect(last_check_called).to eq(true)
+    end
+
+    it 'performs checks in the context of the controller' do
+      check = lambda { |routable| redirect_to routable }
+      allow(subject).to receive(:not_found_actions).and_return([check])
+
+      get_routable(routable)
+
+      expect(response.location).to end_with(routable.to_param)
+    end
+
+    it 'skips checks once one has resulted in a render/redirect' do
+      first_check = proc { render plain: 'first' }
+      second_check = proc { render plain: 'second' }
+      allow(subject).to receive(:not_found_actions).and_return([first_check, second_check])
+
+      get_routable(routable)
+
+      expect(response.body).to eq('first')
+    end
+  end
+end