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Editorial Team
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Asked: 2026-06-08T10:38:08+00:00

I know I’m asking for a lot in this post but after reading 4

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I know I’m asking for a lot in this post but after reading 4 books on Ruby/Rails I’m frustrated by the fact that I’m not getting the “aha” moment. If someone can help I’ll come over and cook you breakfast (for a week).

I’m coming from the world of PHP/MySQL and I’m finding it difficult to grasp certain things in Rails. The last book I read by Michael Hartl suggests some exercises to add to the application he’s built in the book. It has to do with associations. So I was wondering if someone could give me some hints how to go about this because I’m really stuck.

The application he builds is almost a Twitter clone. There are Users who post Microposts. Their home page looks like this http://ruby.railstutorial.org/chapters/following-users#fig:home_page_with_feed The User’s own Microposts are posted along the right hand side in the ‘feed’. Along with the User’s Microposts in the feed are also Microposts by Users that are being followed by the current User. You can follow and unfollow any User you want.

The exercise suggests adding @replies. A @reply is a Micropost starting with @username (e.g. ‘@mikeglaz how are you’). This Micropost will then appear in your feed and the username’s feed (not necessarily someone you’re following). The author suggests the following: ‘This might involve adding an in_reply_to column in the microposts table and an extra including_replies scope to the Micropost model.’ But the associations regarding following other users are pretty complex and this is what’s keeping me stuck. I’ll post some code:

User

class User < ActiveRecord::Base
  attr_accessible :email, :name, :password, :password_confirmation
  has_secure_password
  has_many :microposts, dependent: :destroy
  has_many :relationships, foreign_key: "follower_id", dependent: :destroy
  has_many :followed_users, through: :relationships, source: :followed
  has_many :reverse_relationships, foreign_key: "followed_id",
       class_name:  "Relationship",
       dependent:   :destroy
  has_many :followers, through: :reverse_relationships, source: :follower

  def feed
    Micropost.from_users_followed_by(self)
  end

  def follow!(other_user)
    relationships.create!(followed_id: other_user.id)
  end

  def unfollow!(other_user)
    relationships.find_by_followed_id(other_user.id).destroy
  end
end

end

Relationship

class Relationship < ActiveRecord::Base
  attr_accessible :followed_id

  belongs_to :follower, class_name: "User"
  belongs_to :followed, class_name: "User"
end

Micropost

class Micropost < ActiveRecord::Base
  attr_accessible :content
  belongs_to :user

  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
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1 Answer

  1. Editorial Team

    Hm, what’s your concrete question? You simply don’t have to look at the complicated User associations, that as a hint! (I found them confusing, too, with all the followed and and followed by. But the change mainly goes into the Micropost model, so you should start with that following the hints that Michael Hartl gives.

    If you want to, you can peek at my solution which I added 14 days ago at

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

    • some of the source code might look a bit different, as this version has grown out of the Tutorial for the Rails 3.0 version.
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