I'm struggling since some hours in order to make validations of nested attributes work in my rails app. A small caveat is that I have to validate nested attributes dynamically based off of their parent's attributes, as the amount of info required changes over time according to where in the process the parent is.
So here's my setup: I have a parent with many different associated models and I want to validate subsequently nested attributes of those every time I save the parent. Given the fact that validations change dynamically, I had to write a custom validation method in the model:
class Parent < ActiveRecord::Base
attr_accessible :children_attributes, :status
has_many :children
accepts_nested_attributes_for :children
validate :validate_nested_attributes
def validate_nested_attributes
children.each do |child|
child.descriptions.each do |description|
errors.add(:base, "Child description value cant be blank") if description.value.blank? && parent.status == 'validate_children'
end
end
end
end
class Child < ActiveRecord::Base
attr_accessible :descriptions_attributes, :status
has_many :descriptions
belongs_to :parent
accepts_nested_attributes_for :descriptions
end
In my controller I call update_attributes on the parent when I want to save. Now the problem is that, apparently, rails runs the validations against the database and not against the object that was modified by the user or the controller. So what might happen is that a child's value is erased by a user and the validations will pass, while later validations will not pass because the item in the database is not valid.
Here's a quick example of this scenario:
parent = Parent.create({:status => 'validate_children', :children_attributes => {0 => {:descriptions_attributes => { 0 => {:value => 'Not blank!'}}}})
#true
parent.update_attributes({:children_attributes => {0 => {:descriptions_attributes => { 0 => {:value => nil}}}})
#true!! / since child.value.blank? reads the database and returns false
parent.update_attributes({:children_attributes => {0 => {:descriptions_attributes => { 0 => {:value => 'Not blank!'}}}})
#false, same reason as above
The validation works for first-level associations, e.g. if a Child has a 'value' attribute, I could run a validation the way I do. The problem is with deep associations that apparently cannot be validated before saving.
Could anyone point me in the right direction of how to solve this? The only way I currently see is by saving records, validating them afterwards and deleting / reverting them if the validation fails, but I am honestly hoping for something more clean.
Thank you all in advance!
SOLUTION
So it turns out I was running validations on deep nested models by referencing those directly in the custom validation, this way:
class Parent < ActiveRecord::Base
[...]
has_many :descriptions, :through => :children
[...]
def validate_nested_attributes
descriptions.each do |description|
[...]
end
end
end
Which for some reason leads to the problems I was having above. Thanks Santosh for testing my example code and reporting it was working, this pointed me in the right direction to figure this out.
For future reference, the code in the original question works for this sort of dynamic, deeply-nested validations.
I think you should use validates_associated for this
with the following validation in Child
validates :value, :presence => true, :if => "self.parent.status == 'validate_children'"
Related
I am building a simple Ruby on Rails app for problem management. I have a problem model as follows:
class Problem < ActiveRecord::Base
attr_accessible :active, :impact, :incident_number, :issue_description, :root_cause, :user_id, :problem_summary, :incident_priority, :timeline_enabled
attr_accessor :enable_timeline
validates :problem_summary, :length => { :in => 10..100 }
belongs_to :user
has_one :timeline
has_many :actionitems
end
which has a has_many belongs_to association with the model for actionitems:
class Actionitem < ActiveRecord::Base
attr_accessible :completion_date, :description, :initial_due_date, :notes, :problem_id, :revised_due_date, :status, :user_id
belongs_to :problem
end
I would like to be able to update the problem record and save it with some set of limited validations (I still need to add those). However, I would like to have a "Complete problem investigation" button that would trigger a method on the problem controller to set the :active attribute on the problem record to false. I would like to be able to run a different, more complete set of validations on the problem record prior to performing this action and also to validate that all actionitems (if any) that were associated with this problem record are in :status "completed".
The two questions that I have:
How do I perform a specific set of validations only on a given action?
How can I validate that related instances of Actionitem are in status "complete" prior to performing an action on Problem?
This task seems very complex to me. If you could please point me to what I need to utilize in order to be able to achieve this that would be greatly appreciated! (I read on validates :on => :save etc and accepts_nested_attributes_for but I am not sure how to put all of this together to achieve the behavior that I want).
Many thanks for all your help!
try this
validates_length_of :problem_summary, :in => 10..100, :if => :status_active?
def status_active?
self.active == true
end
see in details - validations & validates_length_of
U need to apply checking conditions on validations like
validate :xyz , length => {:in => 1..12}, :if => , :if => lambda {self.active == true }
this validation will only run when aCTIVE IS TRUE. similarly you can add more validation with checking
I have a structure where an Item may belong to a Claim, and if it does, I want another of its fields to be required as well. These are the relevant code snippets:
class Claim
has_many :items
accepts_nested_attributes_for :items
validates_associated :items
end
class Item
belongs_to :claim
validates :amount_paid, :presence => {:if => :claim}
end
And this works in almost every case. When I edit an existing Claim and try to enter blanks in the amount_paid field, I get the errors I want. And the Claim should exist when it hits this validation, because a previous iteration, which also worked, had the equivalent of
validates :claim_id, :presence => {:unless => :new_claim?}
...
def new_claim?
claim.new_record? # would have thrown an error if claim was nil
end
But when I create a new Claim with blank amount_paid fields on its Items, the validations pass, which they shouldn't.
To no avail, I have also tried
validates :amount_paid, :presence => {:if => :claim_exists?}
...
def claim_exists?
!!claim
end
Any other ideas?
What I've done is possibly a bit of a hack, but it seems to work:
class Item
...
validates :amount_paid, :presence => {:if => :claimed?}
...
def claimed?
!!claim || caller.any? { |m| m =~ /claims_controller/ }
end
end
So if the claim exists, or if this is being called from ClaimsController at any point in the stack trace, the validation will run.
I'd still welcome input from anyone who has a better idea.
I believe the problem can be fixed by adding an :inverse_of option to the associations:
class Claim
has_many :items, :inverse_of => :claim
end
class Item
belongs_to :claim, :inverse_of => :items
end
(It's been a while since I came across this, though, so if you're having the same problem as I was, do a bit of experimentation.)
I have a Project model and a User model. A project must have a client (User class) and so the Project model has a client_id foreign key.
The User model has a type attribute and will contain 3 if the user is a client.
I want to validate that when a project is assigned to a client, that #user.type is 3.
Project.rb
validates :client_id, presence: true, ##user.type must be 3
belongs_to :client, :class_name => User, :foreign_key => :client_id
User.rb
#constants
TYPES = {
:manager => 1,
:contractor => 2,
:client => 3
}
Not to sure how to go about the validation. I read through the rails guide on validations but still can't seem to get a solution. Any ideas?
Use the inclusion validation helper. Docs here
Here's a quick example from the docs
class Coffee < ActiveRecord::Base
validates :size, :inclusion => { :in => %w(small medium large),
:message => "%{value} is not a valid size" }
end
EDIT:
Ok, I see what you mean. Don't use validation helpers for this, do it manually.
# somewhere in your model (don't be tempted to put this in your controller)
def assigning_client
if #user.type == 3
# do the assignment
else
errors.add(:base, :message => "User must be a client")
end
end
The error will prevent the info from being saved as long as you use the bang version save! which forces validation.
Just a pointer here. Don't use an attribute named type in your activerecord models. It conflicts with the way rails uses STI(Single Table Inheritance) as it uses the type attribute to determine the type of the class when its subclassing another
I would like to destroy a nested model if its attributes are blanked out in the form for the parent model - however, it appears that the ActiveRecord::Callbacks are not called if the model is blank.
class Artist < ActiveRecord::Base
using_access_control
attr_accessible :bio, :name, :tour_dates_attributes
has_many :tour_dates, :dependent => :destroy
accepts_nested_attributes_for :tour_dates, :reject_if => lambda { |a| a[:when].blank? || a[:where].blank? }, :allow_destroy => true
validates :bio, :name :presence => true
def to_param
name
end
end
and
class TourDate < ActiveRecord::Base
validates :address, :when, :where, :artist_id, :presence => true
attr_accessible :address, :artist_id, :when, :where
belongs_to :artist
before_save :destroy_if_blank
private
def destroy_if_blank
logger.info "destroy_if_blank called"
end
end
I have a form for Artist which uses fields_for to show the fields for the artist's associated tour dates, which works for editing and adding new tour dates, but if I merely blank out a tour date (to delete it), destroy_if_blank is never called. Presumably the Artist controller's #artist.update_attributes(params[:artist]) line doesn't consider a blank entity worth updating.
Am I missing something? Is there a way around this?
I would keep the :reject_if block but insert :_destroy => 1 into the attributes hash if your conditions are met. (This is useful in the cases where it's not convenient to add _destroy to the form code.)
You have to do an extra check to see if the record exists in order to return the right value but the following seems to work in all cases for me.
accepts_nested_attributes_for :tour_dates, :reject_if => :reject_tour, :allow_destroy => true
def reject_tour(attributes)
exists = attributes['id'].present?
empty = attributes.slice(:when, :where).values.all?(&:blank?)
attributes.merge!({:_destroy => 1}) if exists and empty # destroy empty tour
return (!exists and empty) # reject empty attributes
end
You could apply when all attributes are blank by just changing the empty calculation to:
empty = attributes.except(:id).values.all?(&:blank?)
I managed to do something like this today. Like #shuriu says, your best option is to remove the reject_if option and handle destruction yourself. mark_for_destruction comes in handy :
class Artist < ActiveRecord::Base
accepts_nested_attributes_for :tour_dates
before_validation :mark_tour_dates_for_destruction
def mark_tour_dates_for_destruction
tour_dates.each do |tour_date|
if tour_date.when.blank? || tour_date.where.blank?
tour_date.mark_for_destruction
end
end
end
end
You have code that says the record should be ignored if the 'where' or the 'when' is blank, on the accepts_nested _attributes line, remove the reject_if and your destroy_if blank will likely be called.
Typically to destroy, you would set a _destroy attribute on the nested record, check out the docs http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html
Also, just used cocoon for some of this today, and thought it was awesome, https://github.com/nathanvda/cocoon
Similar to Steve Kenworthy's answer, no local variables.
accepts_nested_attributes_for :tour_dates, :reject_if => :reject_tour, :allow_destroy => true
def reject_tour(attributes)
if attributes[:when].blank? || attributes[:where].blank?
if attributes[:id].present?
attributes.merge!({:_destroy => 1}) && false
else
true
end
end
end
With your current code it's not possible, because of the reject_if option passed to accepts_nested_attributes_for.
As Christ Mohr said, the easiest way is to set the _destroy attribute for the nested model when updating the parent, and the nested model will be destroyed. Refer to the docs for more info on this, or this railscast.
Or you can use a gem like cocoon, or awesome_nested_fields.
To do specifically what you want, you should remove the reject_if option, and handle the logic in a callback inside the parent object. It should check for blank values in the tour_dates_attributes and destroy the nested model. But tread carefully...
I've upgraded to Rails 2.3.3 (from 2.1.x) and I'm trying to figure out the accepts_nested_attributes_for method. I can use the method to update existing nested objects, but I can't use it to create new nested objects. Given the contrived example:
class Product < ActiveRecord::Base
has_many :notes
accepts_nested_attributes_for :notes
end
class Note < ActiveRecord::Base
belongs_to :product
validates_presence_of :product_id, :body
end
If I try to create a new Product, with a nested Note, as follows:
params = {:name => 'Test', :notes_attributes => {'0' => {'body' => 'Body'}}}
p = Product.new(params)
p.save!
It fails validations with the message:
ActiveRecord::RecordInvalid: Validation failed: Notes product can't be blank
I understand why this is happening -- it's because of the validates_presence_of :product_id on the Note class, and because at the time of saving the new record, the Product object doesn't have an id. However, I don't want to remove this validation; I think it would be incorrect to remove it.
I could also solve the problem by manually creating the Product first, and then adding the Note, but that defeats the simplicity of accepts_nested_attributes_for.
Is there a standard Rails way of creating nested objects on new records?
This is a common, circular dependency issue. There is an existing LightHouse ticket which is worth checking out.
I expect this to be much improved in Rails 3, but in the meantime you'll have to do a workaround. One solution is to set up a virtual attribute which you set when nesting to make the validation conditional.
class Note < ActiveRecord::Base
belongs_to :product
validates_presence_of :product_id, :unless => :nested
attr_accessor :nested
end
And then you would set this attribute as a hidden field in your form.
<%= note_form.hidden_field :nested %>
That should be enough to have the nested attribute set when creating a note through the nested form. Untested.
check this document if you use Rails3.
http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html#label-Validating+the+presence+of+a+parent+model
Ryan's solution is actually really cool.
I went and made my controller fatter so that this nesting wouldn't have to appear in the view. Mostly because my view is sometimes json, so I want to be able to get away with as little as possible in there.
class Product < ActiveRecord::Base
has_many :notes
accepts_nested_attributes_for :note
end
class Note < ActiveRecord::Base
belongs_to :product
validates_presence_of :product_id unless :nested
attr_accessor :nested
end
class ProductController < ApplicationController
def create
if params[:product][:note_attributes]
params[:product][:note_attributes].each { |attribute|
attribute.merge!({:nested => true})
}
end
# all the regular create stuff here
end
end
Best solution yet is to use parental_control plugin: http://github.com/h-lame/parental_control