如何获取多态关联中的类型和ID

Question

On the page displaying bibliography, I added the possibility to add a comment.

These are my models:

class Biblio < ApplicationRecord
    has_many :comments, as: :commentable

and:

class Comment < ApplicationRecord
    belongs_to :commentable, polymorphic: true

This is the form for leaving a comment:

<%= form_for @biblio.comments.build, url: administration_create_comment_path do |f| %>
        <%= f.text_field :texte_comment %>
        <%= f.submit %>

The comment controller than contains this:

def create
    @comment = Comment.new(comment_params)
    @comment.save
end

def comment_params
    params.require(:comment).permit(
                    :texte_comment
                    )

end

My question is: how do I get the commentable_type and commentable_id that are created in @biblio.comments.build

Because when I this in a rails console, it works like a charm:

b = Biblio.find(115)
b.commentaires.build
=> #<Commentaire id: nil, utilisateur_id: nil, texte_comment: nil, created_at: nil, updated_at: nil, commentable_type: "Biblio", commentable_id: 115>

In other words: what works in the console, how do I get that in my controller?

Answer 1

You need to send biblio's id on the form submit by adding it as a hidden field in your form:

<%= f.hidden_field :commentable_id %>

Now in your controller you can query with the id in params like this:

def create
   biblio = Biblio.find_by_id(params[:comment][:commentable_id])
   @comment = biblio.commentaires.build(comment_params)
   @comment.save
end