Question

In my rails 3 app I use mongo and mongoid gem with 3 models: (users, friendship, posts).

I need to grab all posts that are from a specific user and his followings.
In traditional rails db will be something like:

Posts.find(:all, :conditions => ["user_id in (?)", friends.map(&:id).push(self.id)], :order => "created_at desc")

How can i do that in mongo?

Actually I don’t know how to use something like “map” and “push”.

Thanks in advance!

Answer 1

Got to http://mongoid.org/docs/querying.html

Posts.where(:user_id => your_user_id).first.friends

Then you can do any map on friends you want.

So looking at your models you can do:

 Post.all_in(:user_id => [your_user.id, your_user.friends.map(&:id)].flatten )

This will return all the posts of that user and his friends