Rails: Get next / previous record

Question

My app has Photos that belong to Users.

In a photo#show view I\'d like to show \"More from this user\", and show a next and previous photo from that user. I would be

Answer 1

class Photo < ActiveRecord::Base
  belongs_to :user

  default_scope { order('published_at DESC, id DESC') }

  def next
    current = nil
    user.photos.where('published_at >= ?', published_at).each do |p|
      if p.id == id then break else current = p end
    end
    return current
  end

  def previous
    current = nil
    user.photos.where('published_at <= ?', published_at).reverse.each do |p|
      if p.id == id then break else current = p end
    end
    return current
  end
end

I found that the answers already here did not serve my case. Imagine that you want a previous or next based on the date published, but some photos are published on the same date. This version will loop through the photos in the order they are rendered on the page, and take the ones before and after the current one in the collection.