CODEWITHSUNDEEP
ruby-on-railsrubyactiverecordmodel
ETSchmidt
ETSchmidt

Reputation: 37

Rails count number of Users who favorited Post

Relatively new to rails, and am just trying to sort through my model relationships in order to find the number of users who have Favorited a particular post. Here are my models:

User.rb

has_many :favorites
has_many :favorite_posts, through: :favorites, source: :favorited, source_type: 'Post'

Post.rb

  belongs_to :user
  has_many :favorites

Favorite.rb

belongs_to :favorited, polymorphic: true
belongs_to :user

In my Posts#show view I want to call something like

<%= @post.favorited.count %>

and get the number of users who have favorited this post, but it tells me that this is an undefined method.

Any suggestions? thank you,

Upvotes: 1

Views: 342

Answers (2)

max
max

Reputation: 102046

class User
  has_many :favorites
  has_many :favorite_posts, through: :favorites, 
                            source: :favorited, 
                            source_type: 'Post'
end

class Post
  has_many :favorites, as: :favorited
end

class Favorite
  belongs_to :user
  belongs_to :favorited, polymorphic: true
end

This will let get a count through @post.favorites.size - but you should either use a join or counter caches to avoid N+1 query issues.

class Favorite
  belongs_to :user
  belongs_to :favorited, polymorphic: true, counter_cache: true
end

Upvotes: 0

chris raethke
chris raethke

Reputation: 435

@engineersmnky is right, you will need to include the relationship on Post as well.

Additionally while you can get this information via a join, it won't let you efficiently query the top favorited posts or include the number of favorites in a table of posts. You should persist the count each time a favorite is added or removed, either using callbacks or a counter cache.

Upvotes: 2

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