notifications_all.rb

notifications_all.rb

#-----数据库schema
#attachable 为虚拟属性，为兼容以后的私信notif之类的
create_table :notifications do |t|
  t.belongs_to :user
  t.references :attachable, :polymorphic => true
  t.text       :content
  t.timestamps
end
add_index :notifications, :user_id
add_index :notifications, [:attachable_id, :attachable_type]
#------end


class User < ActiveRecord::Base
 include Redis::Objects

 has_many :notifications

 list :notifs #利用redis的list来存储未读notification标识
 
 def notifs_count
   self.notifs.size
 end
 
 memoize :notifs_count

end

class NotificationsController < ApplicationController
 before_filter :authenticate
 before_filter :do_for_notif, :only => [:index]

 private
  def do_for_notif
	 current_user.notifs.clear #点击查看Notifications列表时候清空notifs
  end
end

class TopicsController < ApplicationController
 before_filter :find_topic, :except => [:index,:new]
 before_filter :do_for_notif, :only => [:show]


 private
  def find_topic
    @topic = Topic.find(params[:id])
  end

  def do_for_notif
	  if signed_in?
		  current_user.notifs.delete("Topic::#{@topic.id}") #清除 notif
	  end
  end
end


#利用Resque异步处理Notif
class TopicNotif
  @queue = :notif_serve

  def self.perform(user_id, topic_id, text)
    usernames = extract_mentioned_screen_names(text).uniq
    usernames.each do |username|
      user = User.where(:name=>username).first
      if user && user.id != user_id
        content = "" #这里处理需要显示的提示文字
        user.notifications.build(:attachable_id=>topic_id, :attachable_type=>'Topic', :content=>content).save
        user.notifs << "Topic::#{topic_id}"
      end
    end
  end
end

class Topic < ActiveRecord::Base
  after_create :async_for_notif
  
  def async_for_notif
    Resque.enqueue(TopicNotif, self.user_id, self.id, self.title+self.body)
  end
end

class Post < ActiveRecord::Base
  after_create :async_for_notif
  
  def async_for_notif
    Resque.enqueue(TopicNotif, self.user_id,  self.topic_id, self.body) unless self.major
  end
end



#views 
<%= current_user.notifs_count > 200 ? '200+' : current_user.notifs_count %> 条提醒