Merge branch 'dz-refactor-contraints' into 'master'

Refactor routing constraints

## What does this MR do?

Refactors routing constraints

## Why was this MR needed?

This refactoring make it possible to introduce nesting namespaces and project constrainer in future. 

## What are the relevant issue numbers?

Extracted from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7121/

See merge request !7327

4 files changed, 39 insertions, 32 deletions

diff --git a/lib/constraints/constrainer_helper.rb b/lib/constraints/constrainer_helper.rb
new file mode 100644
index 00000000000..ab07a6793d9
--- /dev/null
+++ b/lib/constraints/constrainer_helper.rb
@@ -0,0 +1,15 @@
+module ConstrainerHelper
+  def extract_resource_path(path)
+    id = path.dup
+    id.sub!(/\A#{relative_url_root}/, '') if relative_url_root
+    id.sub(/\A\/+/, '').sub(/\/+\z/, '').sub(/.atom\z/, '')
+  end
+
+  private
+
+  def relative_url_root
+    if defined?(Gitlab::Application.config.relative_url_root)
+      Gitlab::Application.config.relative_url_root
+    end
+  end
+end
diff --git a/lib/constraints/group_url_constrainer.rb b/lib/constraints/group_url_constrainer.rb
index ca39b1961ae..2af6e1a11c8 100644
--- a/lib/constraints/group_url_constrainer.rb
+++ b/lib/constraints/group_url_constrainer.rb
@@ -1,7 +1,15 @@
-require 'constraints/namespace_url_constrainer'
+require_relative 'constrainer_helper'
 
-class GroupUrlConstrainer < NamespaceUrlConstrainer
-  def find_resource(id)
-    Group.find_by_path(id)
+class GroupUrlConstrainer
+  include ConstrainerHelper
+
+  def matches?(request)
+    id = extract_resource_path(request.path)
+
+    if id =~ Gitlab::Regex.namespace_regex
+      Group.find_by(path: id).present?
+    else
+      false
+    end
   end
 end
diff --git a/lib/constraints/namespace_url_constrainer.rb b/lib/constraints/namespace_url_constrainer.rb
deleted file mode 100644
index 91b70143f11..00000000000
--- a/lib/constraints/namespace_url_constrainer.rb
+++ /dev/null
@@ -1,24 +0,0 @@
-class NamespaceUrlConstrainer
-  def matches?(request)
-    id = request.path
-    id = id.sub(/\A#{relative_url_root}/, '') if relative_url_root
-    id = id.sub(/\A\/+/, '').split('/').first
-    id = id.sub(/.atom\z/, '') if id
-
-    if id =~ Gitlab::Regex.namespace_regex
-      find_resource(id)
-    end
-  end
-
-  def find_resource(id)
-    Namespace.find_by_path(id)
-  end
-
-  private
-
-  def relative_url_root
-    if defined?(Gitlab::Application.config.relative_url_root)
-      Gitlab::Application.config.relative_url_root
-    end
-  end
-end
diff --git a/lib/constraints/user_url_constrainer.rb b/lib/constraints/user_url_constrainer.rb
index 504a0f5d93e..4d722ad5af2 100644
--- a/lib/constraints/user_url_constrainer.rb
+++ b/lib/constraints/user_url_constrainer.rb
@@ -1,7 +1,15 @@
-require 'constraints/namespace_url_constrainer'
+require_relative 'constrainer_helper'
 
-class UserUrlConstrainer < NamespaceUrlConstrainer
-  def find_resource(id)
-    User.find_by('lower(username) = ?', id.downcase)
+class UserUrlConstrainer
+  include ConstrainerHelper
+
+  def matches?(request)
+    id = extract_resource_path(request.path)
+
+    if id =~ Gitlab::Regex.namespace_regex
+      User.find_by('lower(username) = ?', id.downcase).present?
+    else
+      false
+    end
   end
 end