Rails:管理已读/未读消息

Question

对于类似论坛的应用程序,我需要能够向每个用户显示未读(新)消息.是否有任何Rails插件/ gem用于此目的？

或者:有没有任何提示以有效的方式完成这项工作？我正在考虑一个额外的数据库表,为每个用户存储每条消息的未读状态(或读状态？).但这似乎是蛮力的方法,也许有一个更聪明的解决方案......

祝愿乔治

Answer 1

与此同时,我根据上面的想法创建了一个Rails插件,但是使用了更加改进的算法.在这里查看:http:
//github.com/ledermann/unread

Answer 2

它可能涉及到谁,这是我的解决方案.我添加了一个用于存储读取状态的新表.此表中的一行给出了用户在给定主题中到目前为止已阅读的帖子数.如果主题有更多帖子,那么用户已阅读,则称为"未读"主题.

用法:

# Get number of unread posts of the logged-in user:
Discussion.unread_by(current_user).count
# => 42

# Mark a topic as read
some_topic = Discussion.find(x)
some_topic.read_by!(current_user)

简单模型"ReadStatus":

class ReadStatus < ActiveRecord::Base
  belongs_to :user
  belongs_to :discussion

  validates_presence_of :user_id, :discussion_id, :post_count
end

从模型"讨论"中提取,用于存储主题和帖子:

class Discussion < ActiveRecord::Base
  belongs_to :user
  belongs_to :topic, :class_name => 'Discussion', :foreign_key => 'discussion_id'

  named_scope :unread_by, lambda { |user| 
      { :joins => "LEFT JOIN read_statuses ON (read_statuses.user_id = #{user} AND 
                                               read_statuses.discussion_id = discussions.id)",
        :conditions => "discussions.discussion_id IS NULL
                        AND (read_statuses.user_id IS NULL) OR (read_statuses.post_count < discussions.post_count)",
        :order => 'discussions.updated_at DESC' 
      }
  }


  def read_by!(user)
    if read_status = ReadStatus.first(:conditions => { :user_id => user.id, :discussion_id => self.id })
      read_status.update_attributes! :post_count => self.post_count
    else
      ReadStatus.create! :user_id => user.id, :discussion_id => self.id, :post_count => self.post_count
    end
  end
end