How are params passed from the New to Create action in Rails?

Question

I understand that the new action for a rails form normally instantiates a model and provides a view with inputs for permitted params.

def new
  @post = Post.new
end

What I don't get is how that same information submitted by the user is carried over to Post.new method inside the create action:

def create
  @post = Post.new(post_params)
  ...
end

How does rails channel these params to create despite the page refresh that occurs?

Answer 1

You are mixing two requests with each other. When you hit the new action, a view that contains your form gets rendered. As it gets rendered, the new action finishes, and now the new action has nothing to do with create action.

You need new action to create a form through form_for method in which you actually pass an object, in your case @post .

The create action is independent, and params it receives, they have nothing to do with new method, those params are received through form rendered in the new.html.erb file of views.

You can also invoke the create method in your controller by sending the data through AJAX or even using cURL or POSTMAN - a chrome extension.

And as you asked:

How does rails channel these params to create despite the page refresh that occurs?

Rails doesn't channel these params , Rails run at back-end, Rails just receives those params . They are sent through an HTML form, and as I said earlier there are other ways to send params as well.