What is flash hash in ruby on rails

Question

I am an experienced PHP developer but new to RoR and trying to understand how every thing works. I know how to use flash hash i.e in my action method, I'll set

flash[:notice] = 'some message'

and in my view, i'll display that. This mechanism is also implemented in Yii framework. I understand how it works there. The thing that I don't understand is how it actually works here in RoR. flash is just a local variable then how can I access it in my views?

Answer 1

flash is actually a method. It's not in your controller, but the Rails controller delegates it to the request object. So the flash method is defined in the request object, but you can access it from your controllers, and from the view.

Check the link to the ActionDispatch::Request code. The flash is actually stored inside the session when set. The next time the user requests a page, the flash is accessible for use in the views.

In your view you can just access it like this:

<%= flash[:notice] %>

Or in a aesthetically more pleasant way (this can only be done with notice and alert since they're so frequently used):

<%= flash.notice %>

See the documentation for more information.