Introduce reactions feature (so-called "like button") to issues, notes, news, and forums (#42630).

Patch by Katsuya HIDAKA (user:hidakatsuya).


git-svn-id: https://svn.redmine.org/redmine/trunk@23755 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/redmine/reaction.rb

@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+# Redmine - project management software
+# Copyright (C) 2006-  Jean-Philippe Lang
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+module Redmine
+  module Reaction
+    # Types of objects that can have reactions
+    REACTABLE_TYPES = %w(Journal Issue Message News Comment)
+
+    # Returns true if the user can view the reaction information of the object
+    def self.visible?(object, user = User.current)
+      Setting.reactions_enabled? && object.visible?(user)
+    end
+
+    # Returns true if the user can add/remove a reaction to/from the object
+    def self.writable?(object, user = User.current)
+      user.logged? && visible?(object, user) && object&.project&.active?
+    end
+
+    module Reactable
+      extend ActiveSupport::Concern
+
+      included do
+        has_many :reactions, as: :reactable, dependent: :delete_all
+
+        attr_writer :reaction_detail
+      end
+
+      class_methods do
+        # Preloads reaction details for a collection of objects
+        def preload_reaction_details(objects)
+          return unless Setting.reactions_enabled?
+
+          details = ::Reaction.build_detail_map_for(objects, User.current)
+
+          objects.each do |object|
+            object.reaction_detail = details.fetch(object.id) { ::Reaction::Detail.new }
+          end
+        end
+      end
+
+      def reaction_detail
+        # Loads and returns reaction details if they are not already loaded.
+        # This is intended for cases where explicit preloading is unnecessary,
+        # such as retrieving reactions for a single issue on its detail page.
+        load_reaction_detail unless defined?(@reaction_detail)
+        @reaction_detail
+      end
+
+      def load_reaction_detail
+        self.class.preload_reaction_details([self])
+      end
+    end
+  end
+end