Pages API: Make domain lookup case-insensitive

When searching for Pages custom domains in /internal/pages use
case-insensitive search in order to handle custom domains with mixed
case.

Related to https://gitlab.com/gitlab-org/gitlab/issues/207390.

app/models/pages_domain.rb

@@ -67,6 +67,10 @@ class PagesDomain < ApplicationRecord
 
   scope :instance_serverless, -> { where(wildcard: true, scope: :instance, usage: :serverless) }
 
+  def self.find_by_domain_case_insensitive(domain)
+    find_by("LOWER(domain) = LOWER(?)", domain)
+  end
+
   def verified?
     !!verified_at
   end

changelogs/unreleased/207390-pages-api-case-insensitive-domain-lookup.yml

+---
+title: 'Add index on LOWER(domain) for pages_domains'
+merge_request: 25664
+author:
+type: other

db/migrate/20200221023320_add_index_on_pages_domain_on_domain_lowercase.rb

+# frozen_string_literal: true
+
+class AddIndexOnPagesDomainOnDomainLowercase < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  INDEX_NAME = 'index_pages_domains_on_domain_lowercase'
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :pages_domains, 'LOWER(domain)', name: INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index_by_name :pages_domains, INDEX_NAME
+  end
+end

db/schema.rb

@@ -3061,6 +3061,7 @@ ActiveRecord::Schema.define(version: 2020_02_21_144534) do
     t.boolean "wildcard", default: false, null: false
     t.integer "usage", limit: 2, default: 0, null: false
     t.integer "scope", limit: 2, default: 2, null: false
+    t.index "lower((domain)::text)", name: "index_pages_domains_on_domain_lowercase"
     t.index ["certificate_source", "certificate_valid_not_after"], name: "index_pages_domains_need_auto_ssl_renewal", where: "(auto_ssl_enabled = true)"
     t.index ["domain", "wildcard"], name: "index_pages_domains_on_domain_and_wildcard", unique: true
     t.index ["project_id", "enabled_until"], name: "index_pages_domains_on_project_id_and_enabled_until"

lib/api/internal/pages.rb

@@ -36,7 +36,7 @@ module API
               present virtual_domain, with: Entities::Internal::Serverless::VirtualDomain
             else
               # Handle Pages domains
-              host = Namespace.find_by_pages_host(params[:host]) || PagesDomain.find_by_domain(params[:host])
+              host = Namespace.find_by_pages_host(params[:host]) || PagesDomain.find_by_domain_case_insensitive(params[:host])
               no_content! unless host
 
               virtual_domain = host.pages_virtual_domain

spec/models/pages_domain_spec.rb

@@ -642,4 +642,12 @@ describe PagesDomain do
       end
     end
   end
+
+  describe '.find_by_domain_case_insensitive' do
+    it 'lookup is case-insensitive' do
+      pages_domain = create(:pages_domain, domain: "Pages.IO")
+
+      expect(PagesDomain.find_by_domain_case_insensitive('pages.io')).to eq(pages_domain)
+    end
+  end
 end

spec/requests/api/internal/pages_spec.rb

@@ -141,21 +141,29 @@ describe API::Internal::Pages do
         context 'custom domain' do
           let(:namespace) { create(:namespace, name: 'gitlab-org') }
           let(:project) { create(:project, namespace: namespace, name: 'gitlab-ce') }
-          let!(:pages_domain) { create(:pages_domain, domain: 'pages.gitlab.io', project: project) }
+          let!(:pages_domain) { create(:pages_domain, domain: 'pages.io', project: project) }
 
           context 'when there are no pages deployed for the related project' do
             it 'responds with 204 No Content' do
-              query_host('pages.gitlab.io')
+              query_host('pages.io')
 
               expect(response).to have_gitlab_http_status(:no_content)
             end
           end
 
           context 'when there are pages deployed for the related project' do
+            it 'domain lookup is case insensitive' do
+              deploy_pages(project)
+
+              query_host('Pages.IO')
+
+              expect(response).to have_gitlab_http_status(:ok)
+            end
+
             it 'responds with the correct domain configuration' do
               deploy_pages(project)
 
-              query_host('pages.gitlab.io')
+              query_host('pages.io')
 
               expect(response).to have_gitlab_http_status(:ok)
               expect(response).to match_response_schema('internal/pages/virtual_domain')