with_scope and a special relationship

rubyonrails-talk
1

Hi!

I have a little problem with two specially related models and an accesor for one of them.

In our application, we have users (with a rights/roles subsystem) and documents. For each document, we have some users related to it, each one playing one role in that document. Some of them:

class Document < ActiveRecord::Base

belongs_to :adviser, :class_name => 'User', :foreign_key => 'adviser_id' belongs_to :owner, :class_name => 'User', :foreign_key => 'owner_id'

end

Documents are related to users this way, but users are related to documents thinking that a user has a document if he participe in some of the posible roles (adviser, owner...). But some special users have access to more documents that those ones (for example, they can have access to all documents created and associated on his office, that it's another attribute of both the document and the user models). So, instead of use has_many :documents on User model, we created the following method on the User model:

class User < ActiveRecord::Base

def documents     if self.can('view all documents')       Document.find :all     elsif self.can('view all office documents')       Document.find :all, :conditions => { :office_id => self.office_id }     else # show only documents with direct user participation       Document.find :all, :conditions => "(adviser_id = #{self.id} or owner_id = #{self.id})"     end end

end

This works very well, but now we have a little problem. We want to use the User::documents method by adding some additional conditions or other find parameters, because we use customizable pagination, and a selector to allow the users to filter the documents. Something like:

current_user.documents :conditions => 'status = 3', :limit => 20

We first tried to use with_scope:

def documents(options = {})   with_scope :find => options do     if self.can('view all documents')       Document.find :all     elsif self.can('view all office documents')       Document.find :all, :conditions => { :office_id => self.office_id }     else # show only documents with direct user participation       Document.find :all, :conditions => "(adviser_id = #{self.id} or owner_id = #{self.id})"     end   end end

But didn't work. Of course, we can create a method with all the possibilities as parameters, and merge the conditions, but that is boring (and doesn't look well).

Is there any other "Ruby-way" alternative?

Thanks!

2

Ok, describing you the problem I found a solution:

class User < ActiveRecord::Base

  def documents(options = {})     Documents.find_by_user(self, options)    end

end

class Document < ActiveRecord::Base

  def self.find_by_user(user, options = {})     with_scope :find => options do       if user.can('view all documents')         find :all       elsif user.can('view all office documents')         find :all, :conditions => { :office_id => user.office_id }       else         find :all, :conditions => "(adviser_id = #{user.id} or owner_id = #{user.id})"       end     end   end

end

It seems that with_scope :find only worked on the Document model. I don't know exactly why, because my knowledge about with_scope is minimum.

Anyway, I will grateful any suggestions.

3

Ok, my last approach lets me use find parameters, but I can't use other ActiveRecord methods like paginate:

current_user.documents.paginate ...

because documents returns an array, and paginate doesn't exist

If I use any other relationship defined with has_many, I can use ActiveRecord methods, because what it returns is an ActiveRecord class with predefined conditions (doesn't it?). For example, I can use:

current_user.roles.paginate ...