CODEWITHSUNDEEP
ruby-on-railscancan
Eric M.
Eric M.

Reputation: 5539

How do I tell CanCan to fetch only specific records?

I have posts that I am trying to load, but only want to load those where the published_at attribute is not nil. I've tried various combinations as mentioned in the wiki docs, but keeping getting exceptions and am not sure what I'm missing. How do I tell CanCan that any user can :read posts that have published_at != nil?

Upvotes: 1

Views: 2166

Answers (3)

roychri
roychri

Reputation: 2936

Simply think the other way around and use cannot method instead.

# If it is NOT hidden, allow to read
can :read, Post, :hidden_at => nil

# If it is NOT published, disallow the read
cannot :read, Post, :published_at => nil

You must call the cannot method AFTER the can method call as explained in Ability Precedence

Upvotes: 0

Spyros
Spyros

Reputation: 48626

In your Ability.rb :

can :edit, Post do |post|
  post.published_at.nil?
end

If you are really talking about CanCan authorization and not querying for posts :) In case you just want to query, a scope will do in your Post model:

scope :not_published, where(:published_at => nil)

EDIT: scope for NOT nil :

scope :published, where('published_at is not NULL')

Upvotes: 3

kobaltz
kobaltz

Reputation: 7070

I think that this is a bit different. Cancan is used for authorization and not so much querying an index. Would you do something like @books = Book.find(:all, :conditions => ["published_at not null"])

Once you have this configured you can check to see if the user has the ability to update/edit/create/destroy/etc the record. If you want to list them all you would go through the normal indexing of them. If you wanted to add an edit button if the user is able to modify the records then you could put a if can? :update, book then show the edit button.

Upvotes: 1

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