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我完成了 Hartl 的教程，过去几天一直在尝试添加类似 twitter 的 @replies，但无济于事。我在 Microposts 表中添加了一个 in_reply_to 列作为我认为可以用来引用给定用户 ID 的整数。截至目前，我正在使用正则表达式通过 Microposts 控制器搜索与给定用户名的匹配项。

Hartl 建议在 Micropost 模型中使用 include_replies 范围。我承认我不太确定要根据自动关联 rails 创建的内容或我必须告诉它的内容来确定在此范围内包含什么内容。

任何帮助将不胜感激。

用户模型

  has_many :microposts, dependent: :destroy
  has_many :replies, through: :microposts, source: :in_reply_to

  VALID_NAME_REGEX =  /\A[\w+\-.]\z/i
  validates :name, presence: true,
            format: { with: VALID_NAME_REGEX },
            length: { maximum: 20 },
            uniqueness: { case_sensitive: false }

...

  def feed
    Micropost.from_users_followed_by(self)
    Micropost.including_replies
  end

微柱模型

class Micropost < ActiveRecord::Base
  attr_accessible :content
  belongs_to :user
  belongs_to :in_reply_to, class_name: "User"

  validates :user_id, presence: true
  validates :content, presence: true, length: { maximum: 140 }

  default_scope order: 'microposts.created_at DESC'
  scope :including_replies, where("user_id = in_reply_to")

  def self.from_users_followed_by(user)
    followed_user_ids = "SELECT followed_id FROM relationships
                         WHERE follower_id = :user_id"
    where("user_id IN (#{followed_user_ids}) OR user_id = :user_id",
          user_id: user.id)
  end
end

微博控制器

class MicropostsController < ApplicationController
  before_filter :signed_in_user, only: [:create, :destroy]
  before_filter :correct_user,   only: :destroy
  before_filter :reply_to_user, only: :create

  def create
    @micropost = current_user.microposts.build(params[:micropost])
      if @micropost.save
      flash[:success] = "Micropost created!"
      redirect_to root_path
    else
      @feed_items = []
      render 'static_pages/home'
    end
  end

  def destroy
    @micropost.destroy
    redirect_to root_path
  end

  private

    def correct_user
      @micropost = current_user.microposts.find_by_id(params[:id])
      redirect_to root_path if @micropost.nil?
    end

    def reply_to_user
      if reply_to = @micropost.content.match(/\A(@[\w+\-.])\z/i)
      @other_user = User.where(name: reply_to.to_s[1..-1])
        if @other_user && current_user.followed_users.includes(@other_user)
        @micropost.in_reply_to = @other_user.id
        end
      end
    end

end
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1 回答 1

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我已经开始研究这个，我注意到的第一件事是你的正则表达式寻找回复不起作用：

> /\A(@[\w+\-.])\z/i.match("@someName blabla")
=> nil

所以第一个提示：测试你正在实施的每一点。另外，我认为你弄错了关联，我用过

   has_many :replies, foreign_key: "to_id", class_name: "Micropost"

（我已将键从 in_reply_to 重命名为简单的“to”，因为使用下划线时出现了奇怪的弃用警告）。

但是您主要是问如何在Micropost中定义新的范围。我是这样做的：

scope :from_users_followed_by_including_replies, lambda { |user| followed_by_including_replies(user) }

...

def self.followed_by_including_replies(user)
  followed_ids = %(SELECT followed_id FROM relationships
                   WHERE follower_id = :user_id)
  where("user_id IN (#{followed_ids}) OR user_id = :user_id OR to_id = :user_id",
        { :user_id => user })
 end

我希望这会有所帮助。你可以看看我的整个实现

https://github.com/htw-rails/TutorialSampleApp32/tree/reply

于 2012-07-11T20:10:59.213 回答