Question

I need some clearance on scope of instance variables in rails application (not sure if other frameworks have the similar paradigm)

Lets say I have an instance variable

@page_count = some_value

inside a controller’s index action

So, regarding accessibility of this variable. It should be accessible within its view and I guess from model as well.(right?)

Now, if i call some other action(through other request) say, export in the same controller, the variable @page_count wont have its value which was set inside index action

(instance variable would not retain its value between different requests, right?)

Currently to deal with this I am using session scoped variable,

session[page_count] = some_value # inside index action

Now the variable will be available inside other actions, including the export action ( through other request)

Is this is good approach? using sessions? or there are better alternatives for storing values between different requests?

Suggestions/Comments/pointers, please?

Answer 1

I think it depends on what you set @page_count to.

If it’s like the number of rows in a db table ‘pages’, and you set it like,

@page_count = Page.all.count

Then you could use a before_filter and set the value there for every controller action you need it. Here’s some more info on filters.

Otherwise, if the value of @page_count is something calculated and changes per action, then I think you just have to define it in every action.