How to get the through instance in a has_many :through relation

Question

I have a has_many :through relation models like:

#foo
has_many :bars, through: link
has_many :links

#link
belongs_to :bar
belongs_to :foo

#bar
has_many :foos, through: link
has_many :links

In a situation where I have a instance of a foo and a instance of a bar how can I get the specific link instance that joins the two together(if it exists)?

Answer 1

I think you could do

foo.links.find_by_bar_id(bar.id)

Answer 2

Maybe

foo.links.where(bar_id: bar.id).first

will do?