Fix the URL of group pages

app/models/project.rb

@@ -1167,12 +1167,16 @@ class Project < ActiveRecord::Base
   def pages_url
     return unless Dir.exist?(public_pages_path)
 
-    host = "#{namespace.path}.#{Settings.pages.host}"
+    # The hostname always needs to be in downcased
+    # All web servers convert hostname to lowercase
+    host = "#{namespace.path}.#{Settings.pages.host}".downcase
+
+    # The host in URL always needs to be downcased
     url = Gitlab.config.pages.url.sub(/^https?:\/\//) do |prefix|
       "#{prefix}#{namespace.path}."
-    end
+    end.downcase
 
-    # If the project path is the same as host, leave the short version
+    # If the project path is the same as host, we serve it as group page
     return url if host == path
 
     "#{url}/#{path}"

doc/pages/README.md

@@ -45,6 +45,14 @@ URL it will be accessible.
 | Specific project under a user's page  | `walter/area51`     | `https://walter.gitlab.io/area51`     |
 | Specific project under a group's page | `therug/welovecats` | `https://therug.gitlab.io/welovecats` |
 
+## Group pages
+
+You can create a group page in context of your group.
+The project for group page must be written in lower.
+
+If you have a group `TheRug` and pages are hosted under `Example.com` in order to create a group page
+create a new project named `therug.example.com`.
+
 ## Enable the pages feature in your project
 
 The GitLab Pages feature needs to be explicitly enabled for each project

spec/models/project_spec.rb

@@ -1845,4 +1845,37 @@ describe Project, models: true do
   def enable_lfs
     allow(Gitlab.config.lfs).to receive(:enabled).and_return(true)
   end
+
+  describe :pages_url do
+    let(:group) { create :group, name: group_name }
+    let(:project) { create :empty_project, namespace: group, name: project_name }
+    let(:domain) { 'Example.com' }
+
+    subject { project.pages_url }
+
+    before do
+      FileUtils.mkdir_p(project.public_pages_path)
+
+      allow(Settings.pages).to receive(:host).and_return(domain)
+      allow(Gitlab.config.pages).to receive(:url).and_return('http://example.com')
+    end
+
+    after do
+      FileUtils.rmdir(project.public_pages_path)
+    end
+
+    context 'group page' do
+      let(:group_name) { 'Group' }
+      let(:project_name) { 'group.example.com' }
+
+      it { is_expected.to eq("http://group.example.com") }
+    end
+
+    context 'project page' do
+      let(:group_name) { 'Group' }
+      let(:project_name) { 'Project' }
+
+      it { is_expected.to eq("http://group.example.com/project") }
+    end
+  end
 end