User Permission export backend changes

Adds API to be used in admin dashboard for download
of user permissions.
The API invokes the export service that generates and returns
the csv file.

app/controllers/application_controller.rb

@@ -286,6 +286,14 @@ class ApplicationController < ActionController::Base
     end
   end
 
+  def stream_csv_headers(csv_filename)
+    no_cache_headers
+    stream_headers
+
+    headers['Content-Type'] = 'text/csv; charset=utf-8; header=present'
+    headers['Content-Disposition'] = "attachment; filename=\"#{csv_filename}\""
+  end
+
   def default_cache_control
     if request.xhr?
       ActionDispatch::Http::Cache::Response::DEFAULT_CACHE_CONTROL

ee/app/controllers/admin/audit_log_reports_controller.rb

@@ -12,11 +12,7 @@ class Admin::AuditLogReportsController < Admin::ApplicationController
 
     respond_to do |format|
       format.csv do
-        no_cache_headers
-        stream_headers
-
-        headers['Content-Type'] = 'text/csv; charset=utf-8; header=present'
-        headers['Content-Disposition'] = "attachment; filename=\"#{csv_filename}\""
+        stream_csv_headers(csv_filename)
 
         self.response_body = csv_data
       end

ee/app/controllers/admin/user_permission_exports_controller.rb

+# frozen_string_literal: true
+
+class Admin::UserPermissionExportsController < Admin::ApplicationController
+  feature_category :users
+
+  before_action :check_user_permission_export_availability!
+
+  def index
+    response = ::UserPermissions::ExportService.new(current_user).csv_data
+
+    respond_to do |format|
+      format.csv do
+        if response.success?
+          stream_csv_headers(csv_filename)
+
+          self.response_body = response.payload
+        else
+          flash[:alert] = _('Failed to generate report, please try again after sometime')
+
+          redirect_to admin_users_path
+        end
+      end
+    end
+  end
+
+  private
+
+  def csv_filename
+    "user-permissions-export-#{Time.current.to_i}.csv"
+  end
+
+  def check_user_permission_export_availability!
+    render_404 unless current_user.can?(:export_user_permissions)
+  end
+end

ee/app/services/members/permissions_export_service.rb → ee/app/services/user_permissions/export_service.rb

 # frozen_string_literal: true
 
-module Members
-  class PermissionsExportService
+module UserPermissions
+  class ExportService
     def initialize(current_user)
       @current_user = current_user
     end

ee/config/routes/admin.rb

@@ -24,6 +24,7 @@ namespace :admin do
       put :revoke
     end
   end
+  resources :user_permission_exports, controller: 'user_permission_exports', only: [:index]
 
   resource :license, only: [:show, :new, :create, :destroy] do
     get :download, on: :member

ee/spec/requests/admin/user_permission_exports_controller_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Admin::UserPermissionExportsController do
+  let_it_be(:admin) { create(:admin) }
+
+  subject { get admin_user_permission_exports_path(format: :csv) }
+
+  before do
+    allow(admin).to receive(:can?).and_call_original
+    allow(admin).to receive(:can?).with(:export_user_permissions).and_return(authorized)
+    sign_in(admin)
+  end
+
+  describe '#index', :enable_admin_mode do
+    context 'when user is authorized' do
+      let(:authorized) { true }
+
+      before do
+        allow(UserPermissions::ExportService).to receive(:new).and_return(export_csv_service)
+      end
+
+      context 'when successful' do
+        let(:csv_data) do
+          <<~CSV
+          Username,Email,Type,Path,Access
+          alvina,alvina@test.com,Group,gitlab-org,Developer
+          jasper,jasper@test.com,Project,gitlab-org/www,Maintainer
+          CSV
+        end
+
+        let(:export_csv_service) do
+          instance_spy(UserPermissions::ExportService, csv_data: ServiceResponse.success(payload: csv_data))
+        end
+
+        it 'responds with :ok', :aggregate_failures do
+          subject
+
+          expect(response).to have_gitlab_http_status(:ok)
+          expect(response.headers['Content-Type']).to eq('text/csv; charset=utf-8; header=present')
+        end
+
+        it 'invokes the Export Service' do
+          subject
+
+          expect(export_csv_service).to have_received(:csv_data)
+        end
+
+        it 'has the appropriate data' do
+          subject
+
+          expect(csv_response).to eq([
+            %w(
+              Username
+              Email
+              Type
+              Path
+              Access
+            ),
+            %w(
+              alvina
+              alvina@test.com
+              Group
+              gitlab-org
+              Developer
+             ),
+            %w(
+              jasper
+              jasper@test.com
+              Project
+              gitlab-org/www
+              Maintainer
+            )
+          ])
+        end
+      end
+
+      context 'when Export fails' do
+        let(:export_csv_service) do
+          instance_spy(UserPermissions::ExportService, csv_data: ServiceResponse.error(message: 'Something went wrong!'))
+        end
+
+        it 'responds appropriately', :aggregate_failures do
+          subject
+
+          expect(flash[:alert]).to eq 'Failed to generate report, please try again after sometime'
+          expect(response).to redirect_to(admin_users_path)
+        end
+      end
+    end
+
+    context 'when user is unauthorised' do
+      let(:authorized) { false }
+
+      it 'responds with :not_found' do
+        subject
+
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
+    end
+
+    def csv_response
+      CSV.parse(response.body)
+    end
+  end
+end

ee/spec/services/members/permissions_export_service_spec.rb → ee/spec/services/user_permissions/export_service_spec.rb

@@ -2,7 +2,7 @@
 
 require 'spec_helper'
 
-RSpec.describe Members::PermissionsExportService do
+RSpec.describe UserPermissions::ExportService do
   let(:service) { described_class.new(current_user) }
 
   let_it_be(:admin) { create(:admin) }

locale/gitlab.pot

@@ -11805,6 +11805,9 @@ msgstr ""
 msgid "Failed to find import label for Jira import."
 msgstr ""
 
+msgid "Failed to generate report, please try again after sometime"
+msgstr ""
+
 msgid "Failed to get ref."
 msgstr ""
 

spec/controllers/application_controller_spec.rb

@@ -720,6 +720,49 @@ RSpec.describe ApplicationController do
     end
   end
 
+  describe '#stream_csv_headers' do
+    controller(described_class) do
+      def index
+        respond_to do |format|
+          format.csv do
+            stream_csv_headers('test.csv')
+
+            self.response_body = fixture_file_upload('spec/fixtures/csv_comma.csv')
+          end
+        end
+      end
+    end
+
+    subject { get :index, format: :csv }
+
+    before do
+      sign_in(user)
+    end
+
+    it 'sets no-cache headers', :aggregate_failures do
+      subject
+
+      expect(response.headers['Cache-Control']).to eq 'no-cache, no-store'
+      expect(response.headers['Pragma']).to eq 'no-cache'
+      expect(response.headers['Expires']).to eq 'Fri, 01 Jan 1990 00:00:00 GMT'
+    end
+
+    it 'sets stream headers', :aggregate_failures do
+      subject
+
+      expect(response.headers['Content-Length']).to be nil
+      expect(response.headers['X-Accel-Buffering']).to eq 'no'
+      expect(response.headers['Last-Modified']).to eq '0'
+    end
+
+    it 'sets the csv specific headers', :aggregate_failures do
+      subject
+
+      expect(response.headers['Content-Type']).to eq 'text/csv; charset=utf-8; header=present'
+      expect(response.headers['Content-Disposition']).to eq "attachment; filename=\"test.csv\""
+    end
+  end
+
   context 'Gitlab::Session' do
     controller(described_class) do
       prepend_before_action do