callback - How do I restrict the number of clients that a user can add in Rails 3? -

basically want happen is, each user ('designer') can add number of clients restricted plan. if plan allows 1 client, that's can do.

my user model looks this:

class user < activerecord::base   devise :database_authenticatable, :confirmable, :registerable, :timeoutable,          :recoverable, :rememberable, :trackable, :validatable, :invitable    has_many :clients,            :through => :client_ownerships,            :order => 'created_at desc'  {edited brevity}  end 

the client model looks this:

class client < activerecord::base     before_save :number_of_clients       belongs_to :user    has_many :projects, :order => 'created_at desc', :dependent => :destroy    has_one :ownership, :dependent => :destroy    has_one :designer, :through => :ownership   validates :name, :presence => true,                    :length => {:minimum => 1, :maximum => 128}    def number_of_clients      authorization.current_user.clients.count < authorization.current_user.plan.num_of_clients       end  end 

the plan model looks this:

# == schema information # schema version: 20110214082231 # # table name: plans # #  id              :integer         not null, primary key #  name            :string(255) #  storage         :float #  num_of_projects :integer #  num_of_clients  :integer #  cached_slug     :string(255) #  created_at      :datetime #  updated_at      :datetime #  price           :integer #  class plan < activerecord::base    has_many :users   has_friendly_id :name, :use_slug => true  end 

rather having number_of_clients method called before_save callback, use validation callback instead:

# app/models/client.rb validate :is_within_plan_limits  def is_within_plan_limits    errors.add(:client, 'you cannot add client') if user.max_clients? end  # app/models/user.rb def max_clients?   authorization.current_user.clients.count > authorization.current_user.plan.num_of_clients end  # app/controllers/client_controller.rb def new   redirect_to(some_path, :notice => 'time upgrade') , return if current_user.max_clients? end 

see docs on here.

you can check number of clients in controller new action make sure user has free client slot, , direct them upgrade if not. validation enforce ui.