Grapify the LDAP API

lib/api/ldap.rb

 module API
-  # groups API
   class Ldap < Grape::API
     before { authenticate! }
 
     resource :ldap do
       helpers do
         def get_group_list(provider, search)
-          search ||= ""
           search = Net::LDAP::Filter.escape(search)
           Gitlab::LDAP::Adapter.new(provider).groups("#{search}*", 20)
         end
+
+        params :search_params do
+          optional :search, type: String, default: '', desc: 'Search for a specific LDAP group'
+        end
       end
 
-      # Get a LDAP groups list. Limit size to 20 of them.
-      # Filter results by name using search param
-      #
-      # Example Request:
-      #  GET /ldap/groups
+      desc 'Get a LDAP groups list. Limit size to 20 of them.' do
+        success Entities::LdapGroup
+      end
+      params do
+        use :search_params
+      end
       get 'groups' do
         provider = Gitlab::LDAP::Config.servers.first['provider_name']
-        @groups = get_group_list(provider, params[:search])
-        present @groups, with: Entities::LdapGroup
+        groups = get_group_list(provider, params[:search])
+        present groups, with: Entities::LdapGroup
       end
 
-      # Get a LDAP groups list by the requested provider. Lited size to 20 of them.
-      # Filter results by name using search param
-      #
-      # Example Request:
-      #  GET /ldap/ldapmain/groups
+      desc 'Get a LDAP groups list by the requested provider. Limit size to 20 of them.' do
+        success Entities::LdapGroup
+      end
+      params do
+        use :search_params
+      end
       get ':provider/groups' do
-        @groups = get_group_list(params[:provider], params[:search])
-        present @groups, with: Entities::LdapGroup
+        groups = get_group_list(params[:provider], params[:search])
+        present groups, with: Entities::LdapGroup
       end
     end
   end