@H_502_1@我正在尝试建立一个类似于facebook的消息系统,你有一个按两个用户之间的对话排序的消息列表(这对于目前的多个收件人来说并不重要,但也许如果我使用更智能的设计那么它可以将来很容易实现.我认为添加到我现在的东西并不容易.)我有一些工作,但我无法实现一些功能.我对rails / web编程很新,因此非常感谢任何和所有提示/提示/解决方案.

所以我有三个相关的模型：User,Conversation和Messages.用户有很多会话,Conversation有很多消息,属于Users,Message属于Conversation.好的,这就是模型的样子：

用户：具有相关字段ID：int,username：string

class User < ActiveRecord::Base

  has_many :conversations,:class_name => "Conversation",:finder_sql =>
            proc { 
            "SELECT * FROM conversations " +
            "WHERE conversations.user1_id = #{id} OR conversations.user2_id = #{id} " +
            "ORDER BY conversations.updated_at DESC" }

会话：有相关字段：ID：int,user1_id：int,user2_id：int,user1_deleted：boolean,user2_deleted：boolean,created_at：datetime,updated_at：datetime

class Conversation < ActiveRecord::Base
  has_many :messages  

  belongs_to :participant_one,:class_name => "User",:foreign_key => :user1_id
  belongs_to :participant_two,:foreign_key => :user2_id

  private

    def self.between(user1,user2)
      c = Conversation.arel_table
      Conversation.where(c[:user1_id].eq(user1).and(c[:user2_id].eq(user2)).or(c[:user1_id].eq(user2).and(c[:user2_id].eq(user1))))

消息：具有相关字段：id：int,conversation_id：int,author_id：int,content：text,updated_at：datetime

class Message < ActiveRecord::Base
  belongs_to :conversation,:touch => true

我不确定我是否需要participant_one和participant_two,但我使用了

def conversation_partner(conversation)
    conversation.participant_one == current_user ? conversation.participant_two : conversation.participant_one
  end

在ConversationHelper中,以便在视图中,我可以显示其他参与者.

所以这基本上有效.但我遇到的一个复杂问题是我在Conversation中并没有真正区分用户,用户可以在user1字段或user2字段中.所以我需要不断地在一个或另一个领域中寻找用户,例如在用户has_many声明的finder_sql中.此外,当我创建新消息时,我首先搜索是否存在Conversation参数,或者如果没有,则查看两个用户之间是否有对话,如果没有,则创建新对话. (您可以从会话索引发送消息(如回复),或者current_user可以查看另一个用户并单击“向该用户发送消息”链接.messagecontroller看起来像这样,并使用该自我.在Conversation模型中的方法之间：

class MessagesController < ApplicationController
  before_filter :get_user
  before_filter :find_or_create_conversation,:only => [:new,:create]

  def new
     @message = Message.new
  end

  def create
    @message = @conversation.messages.build(params[:message])
    @message.author_id = current_user.id
    if @message.save
      redirect_to user_conversation_path(current_user,@conversation),:notice => "Message sent!"
    else
      redirect_to @conversation
    end
  end

  private
     def get_user
      @user = User.find(params[:user_id])
    end

    def find_or_create_conversation
      if params[:conversation_id]
        @conversation = Conversation.find(params[:conversation_id]) 
      else
        @conversation = Conversation.between(@user.id,current_user.id).first or @conversation = Conversation.create!(:user1_id => current_user.id,:user2_id => @user.id)
      end
    end

(我的路线看起来像这样:)

resources :users do
    resources :conversations,:only => [:index,:create,:show,:destroy] do
      resources :messages,:create]
    end
    resources :messages,:only => [:new]
  end

所以现在,我在尝试设置user1_deleted或user2_deleted标志时遇到问题. (同样,如果/当我实现读取/最新标志时).问题是因为同一个用户可以有很多对话,但他可以是user1或user2,很难找到他.我以为我可以在Conversation模型中做这样的事情：

def self.active(user)
  Conversation.where(which_user?(user) + "_deleted = ?",false)
end

def self.which_user?(user)
  :user1_id == user ? 'user1' : 'user2'
end

但是,除非你逐个遍历用户的每个对话,否则你无法运行整个对话,因为有时他是user1,有时候他是user2.我应该抛弃这整个方法并尝试新的设计吗？如果是这样,有没有人可能更优雅/更好/实际工作并仍然满足相同的需求？

这是一个很长的问题,所以我很欣赏任何愿意和我一起讨论这一切的人.谢谢.

class User < ActiveRecord::Base
  has_many :user_conversations
  has_many :conversations,:through => :user_conversations
  has_many :messages,:through => :conversations
end

class UserConversation < ActiveRecord::Base
  belongs_to :user
  belongs_to :conversation
  has_many :messages,:through => :conversation

  delegate :subject,:to => :conversation
  delegate :users,:to => :conversation
end

class Conversation < ActiveRecord::Base
  has_many :user_conversations
  has_many :users,:through => :user_conversations
  has_many :messages
end

class Message < ActiveRecord::Base
  belongs_to :user
  belongs_to :conversation
end

create_table "conversations",:force => true do |t|
  t.string   "subject"
  t.datetime "created_at"
  t.datetime "updated_at"
end

create_table "messages",:force => true do |t|
  t.integer  "user_id"
  t.integer  "conversation_id"
  t.text     "body"
  t.datetime "created_at"
  t.datetime "updated_at"
end

create_table "user_conversations",:force => true do |t|
  t.integer  "user_id"
  t.integer  "conversation_id"
  t.boolean  "deleted"
  t.boolean  "read"
  t.datetime "created_at"
  t.datetime "updated_at"
end

create_table "users",:force => true do |t|
  t.string   "name"
  t.datetime "created_at"
  t.datetime "updated_at"
end