RemoteProject and Project changes to manage them like same kind of objects

project.rb

# Update this methods in the Project class
class Project
  
  def is_remote?
    false
  end
  
  # returns an object of project(local or remote) or raises an exception
  def self.get_by_name(project_name, options = {})
    project = find_by(name: project_name)
    project = RemoteProject.find_by(name: project_name) unless project
    raise UnknownObjectError, project_name unless project
    
    # TODO: Verify how should be check the access on remote projects
    # This permissions checking should be outside the model
    if options[:includeallpackages] && !project.is_remote?
      Package.joins(:flags).where(project_id: project.id).where("flags.flag='sourceaccess'").each do |package|
        raise ReadAccessError, project_name unless Package.check_access?(package)
      end
    end
    raise ReadAccessError, project_name unless !project.is_remote? && check_access?(project.name)

    project
  end
  
  def self.is_remote_project?(project_name, skip_access = false)
    RemoteProject.exists?(project_name)
  end
  
  # check existence of a project (local or remote)
  def self.exists_by_name(project_name)
    local_project = find_by(name: project_name)
    if local_project
      check_access?(local_project.name)
    else  # TODO: Verify how should be check the access on remote projects
      RemoteProject.exists?(project_name)
    end
  end
  
end

remote_project.rb

# Remote projects: They are not in the DB, but we will have objects loaded from the backend that represent them
class RemoteProject

  include ActiveModel::Model
  include ActiveModel::Serializers::Xml
  
  attr_accessor :name, :title, :description # TODO: put all the attributes needed for a remote project
 
  # this is needed for the Xml Serializer
  def attributes=(hash)
    hash.each do |key, value|
      send("#{key}=", value)
    end
  end
 
  def attributes
    {name: nil, title: nil, description: nil} # TODO: put all the attributes needed for a remote project
  end
  
  # Remote projects are readonly always, maybe they should raise an exception or just fill an error array
  def destroy false end 
  def destroy! false end 
  def save false end 
  def save! false end 
    
  def is_remote?
    true
  end
  
  def self.find_by(options = {})
    # TODO: Read from backend and fill attributes with that
    project_name = options[:name]
    xml = Suse::Backend.get() 
    self.from_xml(xml)
  rescue ActiveXML::Transport::NotFoundError
    nil
  end
  
  def self.exists?(project_name)
    # TODO: Read from backend to check existence
    name = options[:name]
    Suse::Backend.get()
    true
  rescue ActiveXML::Transport::NotFoundError
    false
  end
  
end

Hm, which relationships are you talking about? A lot of them will be in the project XML you get from remote right? Can we make a list?