Question

I have a controller which has two methods: upload and submit

I can ensure that the upload method is executed before submit is called.

in the upload, I have such code:

def upload
    @file = params[:avatar]
    ...
end

in the submit, I have such code:

def submit
    ...
    user.avatar = @file
    ...
end

but it seems that the @file is nil.

Where am I wrong?….

I’m using Rails 3.2.0

Answer 1

Instance variables in controllers do not persist between requests. Every request creates a new instance of the controller class so the @file you save in upload goes away when upload finishes. Then, when a new request comes in that is routed to your submit method, Rails will create a new instance of your controller class and call submit on it. Since you have two instances of the class, you have two sets of instance variables and they won’t share your @file.

You have to arrange for the @file to be stored in your database, session, form, etc. between requests and then your submit has to load it from where ever it is stored and assign it to user.avatar.