Anonymous asked: I want to know if you could touch on how to make a Quora or Reddit type of feature app using rails 4?Enabling voting on user submitted post,content is becoming a popular feature in most apps but there is not a lot of training material out there showing exactly how to implement,configure voting on post or user submitted links and which gems would be best for the job. I was wondering since you where good at explain these untouched topics, if you could make a video showing exactly how to do this?
Hello, thanks for the question. I have an idea how a simple voting system might work, and it uses the Active Record gem, one of the most powerful sequel database tools out there. It looks like you goal is for users to be able to vote on any type of content on your site, so since we don’t know all the types of content that will one day receive votes I would create a polymophic database table that enables tracking of votes for any other type of object. Polymorphic means that a given record can be associated with many different types of database records. Here are some example Active Record classes that enable polymorphism. After I will explain what they do behind the scenes:
class Vote < ActiveRecord::Base
belongs_to :votable, polymorphic: true
end
class Post < ActiveRecord::Base
has_many :votes, as: :votable
end
class UserLink < ActiveRecord::Base
has_many :votes, as: :votable
end
The polymorphic setting will create two database columns in your Vote table, one called votable_type and one called votable_id. Now every time you want to add a vote for a particular UserLink you create create a new Vote record, setting the votable_id as user_link.id and votable_type as ‘user_links’.
user_link = UserLink.find(1212)
vote = user_link.votes.create
puts [vote.votable_type, vote.votable_id]
=> ['user_links’, 1212]
post = Post.find(999)
vote = post.votes.create
puts [vote.votable_type, vote.votable_id]
=> ['posts’, 999]
Ryan Bates has done two Railscasts on polymorphism and there is a good explanation in the rails guides.
http://railscasts.com/episodes/154-polymorphic-association
http://guides.rubyonrails.org/association_basics.html#polymorphic-associations
I hope this helps!
