【Rails学习笔记】用户关注功能（四）

最后一节是用来实现动态列表。

feed稍作改进：

class User < ActiveRecord::Base
  .
  .
  .
  def feed
    Micropost.from_users_followed_by(self)
  end
  .
  .
  .
end

class Micropost < ActiveRecord::Base
  .
  .
  .
  def self.from_users_followed_by(user)
    followed_user_ids = user.followed_user_ids
    where("user_id IN (?) OR user_id = ?", followed_user_ids, user)
  end
end

class Micropost < ActiveRecord::Base
  belongs_to :user
  default_scope -> { order(created_at DESC) }
  validates :content, presence: true, length: { maximum: 140 }
  validates :user_id, presence: true

  # Returns microposts from the users being followed by the given user.
  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

最后我们要在home中加入对分页功能的支持

class StaticPagesController < ApplicationController

  def home
    if signed_in?
      @micropost  = current_user.microposts.build
      @feed_items = current_user.feed.paginate(page: params[:page])
    end
  end
  .
  .
  .
end