In my rails app I have a User model.
In that model I have some custom validation and a before save block as below
Class User < AvtiveRecord::Base
before_save :save_user
validate :validate_user
def save_user
self.guest = true if(!self.admin? && !self.guest)
end
def validate_user
errors.add(:age, "can't be less than 20") if self.age < 20
end
end
Now, I just wanted to know that whether the validate block executes first or the validate. Because there are other validations based on the user role. So if the validate block executes first and there are no validation errors and then the before save executes and modifies the values. Are those values again validated?
Thanks in Advance.
Validations are called before before_save callbacks. If you want it to execute before the validations then you can use before_validation_on_create or before_validation_on_update, like this:
class User < ActiveRecord::Base
before_validation_on_create :save_user
validate :validate_user
def save_user
self.guest = true if(!self.admin? && !self.guest)
end
def validate_user
errors.add(:age, "can't be less than 20") if self.age < 20
end
end
Those values will not be validated again. Validation happens once as does save, otherwise you could end up in a looping condition anytime you changed a value.
This is the guide you want: http://guides.rubyonrails.org/active_record_validations_callbacks.html
Based on section 10, it looks as if validation happens first.
I don't think the values will be validated again—there's nothing that would cause that to happen.
Related
I have three related models, an Account which has one program and has one profile. When an account is created, profile.email can be nil so long as program.upgraded == 'f'. But how can I, and where should I, validate that profile.email has been set, i.e. is not nil, before setting program.upgraded to 't'.
So I've tried creating a custom validation, but I may not be implementing this properly. I have a service that calls
program.update!(
upgraded: 't',
)
inside a transaction block that rescues on an exception. Here's my validation:
class Account::Program < ApplicationRecord
validate :upgraded, :upgraded_email_present
...
private
def upgraded_email_present
return unless ppc_p == 't' && account.profile.auto_email.blank?
errors[:upgraded] << "profile auto_email must be set"
end
...
end
The update! statement appears to be failing, and it triggers the rescue in that the transaction block is in with the correct error. However, when I check the model instance, it's still been upgraded! Totally confused on what's wrong here.
EDIT
Finally realized what's going on. I was testing the validation in the context of my specs and had to do a reload on the instance. This solution works.
You can use a custom validator (Rails docs) for more complex validations like what you're after. An ActiveModel::EachValidator implements .validate_each, which takes the arguments:
the record being validated
the attribute being validated
the current value of that attribute
class UpgradeEmailPresentValidator < ActiveModel::EachValidator
def validate_each(record, attribute, value)
# All good if :upgraded is false or if the profile email is present
return unless value? && record.account.profile.email.blank?
record.errors[attribute] << (options[:message] || "profile email must be set")
end
end
class Program < ApplicationRecord
validates :upgraded, presence: true, upgrade_email_present: true
end
You didn't say if Program is associated with a Profile via has_one :through, but if it does you can shorten record.account.profile to just record.profile.
EDIT
I neglected to mention in my original that you can also use a custom validation method on the model as well.
class Program < ApplicationRecord
validate :upgraded, :upgrade_email_present
def upgrade_email_present
return unless upgraded? && account.profile.email.blank?
errors[:upgraded] << "profile email must be set"
end
end
I'm trying to handle the situation where the user has entered info incorrectly, so I have a path that follows roughly:
class Thing < AR
before_validation :byebug_hook
def byebug_hook
byebug
end
end
thing = Thing.find x
thing.errors.add(:foo, "bad foo")
# Check byebug here, and errors added
if thing.update_attributes(params)
DelayedJobThatDoesntLikeFoo.perform
else
flash.now.errors = #...
end
byebug for byebug_hook> errors.messages #=> {}
Originally I thought that maybe the model was running its own validations and overwriting the ones I added, but as you can see even when I add the before hook the errors are missing, and I'm not sure what's causing it
ACTUAL SOLUTION
So, #SteveTurczyn was right that the errors needed to happen in a certain place, in this case a service object called in my controller
The change I made was
class Thing < AR
validate :includes_builder_added_errors
def builder_added_errors
#builder_added_errors ||= Hash.new { |hash, key| hash[key] = [] }
end
def includes_builder_added_errors
builder_added_errors.each {|k, v| errors.set(k, v) }
end
end
and in the builder object
thing = Thing.find x
# to my thinking this mirrors the `errors.add` syntax better
thing.builder_added_errors[:foo].push("bad foo") if unshown_code_does_stuff?
if thing.update_attributes(params)
DelayedJobThatDoesntLikeFoo.perform
else
flash.now.errors = #...
end
update_attributes will validate the model... this includes clearing all existing errors and then running any before_validation callbacks. Which is why there are never any errors at the pont of before_validation
If you want to add an error condition to the "normal" validation errors you would be better served to do it as a custom validation method in the model.
class Thing < ActiveRecord::Base
validate :add_foo_error
def add_foo_error
errors.add(:foo, "bad foo")
end
end
If you want some validations to occur only in certain controllers or conditions, you can do that by setting an attr_accessor value on the model, and setting a value before you run validations directly (:valid?) or indirectly (:update, :save).
class Thing < ActiveRecord::Base
attr_accessor :check_foo
validate :add_foo_error
def add_foo_error
errors.add(:foo, "bad foo") if check_foo
end
end
In the controller...
thing = Thing.find x
thing.check_foo = true
if thing.update_attributes(params)
DelayedJobThatDoesntLikeFoo.perform
else
flash.now.errors = #...
end
I have an auction and a bid object in my application, when someone presses the BID BUTTON it then calls the BID CREATE controller which created the bid, and then does some other things on the auction object:
BIDS CONTROLLER -> CREATE
#auction.endtime += #auction.auctiontimer
#auction.winner = #auction.arewinning
#auction.save
AUCTION MODEL
before_update :set_endtime
def set_endtime
self.endtime=self.starttime+self.auctiontimer
end
So the question is: How can C skip the "before callback" only, in this specific #auction.save
skip_callback is a complicated and not granular option.
I prefer to use an attr_accessor:
attr_accessor :skip_my_method, :skip_my_method_2
after_save{ my_method unless skip_my_method }
after_save{ my_method_2 unless skip_my_method_2 }
That way you can be declarative when skipping a callback:
model.create skip_my_method: true # skips my_method
model.create skip_my_method_2: true # skips my_method_2
ActiveSupport::Callbacks::ClassMethods#skip_callback is not threadsafe, it will remove callback-methods for time till it is being executed and hence and another thread at same time cannot get the callback-methods for execution.
Look at the informative post by Allerin - SAVE AN OBJECT SKIPPING CALLBACKS IN RAILS APPLICATION
You can try skipping callback with skip_callback
http://www.rubydoc.info/docs/rails/4.0.0/ActiveSupport/Callbacks/ClassMethods:skip_callback
You can use update_columns
See this http://edgeguides.rubyonrails.org/active_record_callbacks.html#skipping-callbacks
Is there any specific condition like when you don't have endtime then only you need to set end time if that the you can do
def set_endtime
if endtime.nil?
self.endtime=self.starttime+self.auctiontimer
end
end
OR
before_update :set_endtime if: Proc.new { |obj| obj.endtime.nil? }
I have a model that uses after_update to log changes. There is a case where I would like to make a change to the model without activating this logging mechanism. Is there a way to pass in a parameter to after_update, or skip it all together?
I would like a nice solution to this, and am willing to remove after_update if there is a better way to go about it.
I would go with the approach of adding a boolean to the model as suggested but would then write a method to help set and clear the flag after your update. e.g.
def without_logging_changes_to(model)
# store current value of the flag so it can be restored
# when we leave the block
remembered_value = model.log_update
model.log_update = false
begin
yield
ensure
model.log_update = remembered_value
end
end
Then to use it:
without_logging_changes_to my_model do
my_model.update_attributes(updates)
end
You could add a boolean to your model that is something like log_last_update and check that in the after_update callback.
class MyModel < ActiveRecord::Base
after_update :do_something
attr_accessor :should_do_something
def should_do_something?
should_do_something != false
end
def do_something
if should_do_something?
...
end
end
end
y = MyModel.new
y.save! # callback is triggered
n = MyModel.new
n.should_do_something = false
n.save! # callback isn't triggered
In Rails 2 you can use private ActiveRecord methods
update_without_callbacks
create_without_callbacks
They can be invoked via the send method:
# Update attributes on your model
your_model.some_attribute = some_value
# Update model without callbacks
your_model.send(:update_without_callbacks)
For example, if I have a user model and I need to validate login only (which can happen when validating a form via ajax), it would be great if I use the same model validations defined in the User model without actually instantiating a User instance.
So in the controller I'd be able to write code like
User.valid_attribute?(:login, "login value")
Is there anyway I can do this?
Since validations operate on instances (and they use the errors attribute of an instance as a container for error messages), you can't use them without having the object instantiated. Having said that, you can hide this needed behaviour into a class method:
class User < ActiveRecord::Base
def self.valid_attribute?(attr, value)
mock = self.new(attr => value)
unless mock.valid?
return mock.errors.has_key?(attr)
end
true
end
end
Now, you can call
User.valid_attribute?(:login, "login value")
just as you intended.
(Ideally, you'd include that class method directly into the ActiveRecord::Base so it would be available to every model.)
Thank you Milan for your suggestion. Inspired by it I created a simple module one can use to add this functionality to any class. Note that the original Milans suggestion has a logic error as line:
return mock.errors.has_key?(attr)
should clearly be:
return (not mock.errors.has_key?(attr))
I've tested my solution and it should work, but ofc I give no guarantees. And here's my glorious solution. Basically a 2-liner if you take away the module stuff.. It accepts method names as stings or symbols.
module SingleAttributeValidation
def self.included(klass)
klass.extend(ClassMethods)
end
module ClassMethods
def valid_attribute?(attr, value)
mock = self.new(attr => value)
(not mock.valid?) && (not mock.errors.has_key?(attr.class == Symbol ? attr : attr.to_sym))
end
end
end
To use your standard validation routines:
User.new(:login => 'login_value').valid?
If that does not work for you, build a custom class method for this:
class User < ActiveRecord::Base
validate do |user|
user.errors.add('existing') unless User.valid_login?(user.login)
end
def self.valid_login?(login)
# your validation here
!User.exist?(:login=> login)
end
end
I had a hell of a time getting this to work in Rails 3.1. This finally worked. (Not sure if it's the best way to do it, I'm kind of a newb.). The problem I was having was that value was being set to type ActiveSupport::SafeBuffer, and was failing validation.
def self.valid_attribute?(attr, value)
mock = User.new(attr => "#{value}") # Rails3 SafeBuffer messes up validation
unless mock.valid?
return (not mock.errors.messages.has_key?(attr))
end
return true
end
I have gone with the custom class solution but I just wanted to make sure there was no better way
class ModelValidator
def self.validate_atrribute(klass, attribute, value)
obj = Klass.new
obj.send("#{attribute}=", value)
obj.valid?
errors = obj.errors.on(attribute).to_a
return (errors.length > 0), errors
end
end
and I can use it like
valid, errors = ModelValidator.validate_attribute(User, "login", "humanzz")
class User < ActiveRecord::Base
validates_each :login do |record, attr, value|
record.errors.add attr, 'error message here' unless User.valid_login?(value)
end
def self.valid_login?(login)
# do validation
end
end
Just call User.valid_login?(login) to see if login itself is valid
An implementation of the 'valid_attribute' method you are suggesting:
class ActiveRecord:Base
def self.valid_attribute?(attribute, value)
instance = new
instance[attribute] = value
instance.valid?
list_of_errors = instance.errors.instance_variable_get('#errors')[attribute]
list_of_errors && list_of_errors.size == 0
end
end
How about:
User.columns_hash.has_key?('login')