How to pass an object to a controller action?

Question

Ruby on Rails

There is a post controller and a comment controller.
Each post has a lot of comments, respectively.
In the index view of the post controller, along with each post, there is a form for adding a comment to a specific post.
I made a helper that generates an empty comment object (post.comments.build) to pass it to the form.
But how can I make it so that in the create action of the comment controller I create comments on a specific post?
After all, we cannot search for a post by id, for example, like this: post = Post.find_by(id: params[:id]) , because no id is actually transferred anywhere.
Thanks

Answer 1

You made a crutch with hidden field
What would be normal, you need to look at what nested resources routing is

Answer 2

Here 4.3 paragraph read carefully.
Briefly, then

@article = Article.find(params[:article_id])
@comment = @article.comments.create(comment_params) #strong params

more or less like this.
As far as we know, the post id will be passed as params[:post_id].