I’m using Rails 4.2.3. I have three fields in my model — name, first_name, and last_name. would like to have a validation rule in my model that causes a save to fail if the “name” field is empty unless either the first_name or last_name field is not empty. SOoI tried
validates_presence_of :name, :unless => !:first_name.empty? or !:last_name.empty?
but this doesn’t work. I get the error below
undefined method `validate' for true:TrueClass
What is the proper way to write the validation rule above?
Everything you need to know is here.
You can write the rule by defining a separate method for it:
class Whatever < ActiveRecord::Base
validates :name, presence: true, unless: :firstname_or_surname?
def firstname_or_surname?
firstname.present? || surname.present?
end
end
Or you can use a Proc to define it inline:
class Whatever < ActiveRecord::Base
validates :name, presence: true,
unless: Proc.new { |a| a.firstname.present? || a.surname.present? }
end
Related
I'm new to rails, and I'm currently trying to develop an API based app using Rails 5, on one of my controllers I have a function to filter the allow parameters like so
def provider_params
params.require(:provider).permit(:name, :phone, :email, :website, :address, :provider_id, :bio, :specialty_ids => [])
end
Then posting from Paw I noticed that the arguments that are not attributes of the table are no included in provider_params, the parameter I'm supposed to receive is an array, which is defined by a HABTM relation-ship.
This is how my models look like
specialty.rb
class Specialty < ApplicationRecord
has_and_belongs_to_many :providers
end
provider.rb
class Provider < ApplicationRecord
has_and_belongs_to_many :specialties
end
And this is how the join table was created via migration
class CreateProvidersSpecialties < ActiveRecord::Migration[5.0]
def change
create_table :providers_specialties, :id => false do |t|
t.integer :provider_id
t.integer :specialty_id
end
add_index :providers_specialties, :provider_id
add_index :providers_specialties, :specialty_id
end
end
The JSON I'm posting
{
"name": "the name",
"specialty_ids": [
1,
2
]
}
So as I mentioned, the array specialty_ids doesn't seem to be coming through, and even if it did, I suspect there's still something else I need to do in order for rails to insert the content of specialty_ids in the ProvidersSpecialties Table
So the problem was finally solved by removing the requir call from the method provider_params, since I wasn't wrapping the json-payload in a provider key. Apparently once you add the require(:key) call you would only be able to add parameters that belong to the Model, which is weird since an error should be raised when the key is not present, what was the case with my payload, lacking the provider key.
I'm wondering if I miss a way to avoid repeat validation code in my Sequel::Model#validate subclass method since I've already put all constraints into my migration file.
Here's a simple example of what I'm talking about :
Sequel.migration do
change do
create_table :users do
primary_key :id
String :name, :null => false, :unique => true
end
end
end
class User < Sequel::Model
def validate
super
validates_presence :name
validates_unique :name
validates_type String :name
end
end
It seems very painful and errors prone to have to repeat all the constraints in the validate method. Did I miss something or there's no other way to do that ?
Any advice will be appreciated, thanks
Sequel has some nice plugins and extensions.
Sequel::Model.plugin(:auto_validations)
Sequel::Model.plugin(:constraint_validations)
and
DB.extension(:constraint_validations)
auto_validations
The auto_validations plugin automatically sets up three types of
validations for your model columns:
type validations for all columns
not_null validations on NOT NULL columns (optionally, presence
validations)
unique validations on columns or sets of columns with unique indexes
See http://sequel.jeremyevans.net/rdoc-plugins/classes/Sequel/Plugins/AutoValidations.html
constraint_validations
The constraint_validations extension is designed to easily create
database constraints inside create_table and alter_table blocks. It
also adds relevant metadata about the constraints to a separate table,
which the constraint_validations model plugin uses to setup automatic
validations.
See http://sequel.jeremyevans.net/rdoc-plugins/files/lib/sequel/extensions/constraint_validations_rb.html
and
http://sequel.jeremyevans.net/rdoc-plugins/classes/Sequel/Plugins/ConstraintValidations.html
Your example would look like this
Sequel::Model.plugin(:auto_validations)
Sequel::Model.plugin(:constraint_validations)
Sequel.migration do
up do
extension(:constraint_validations)
create_table :users do
primary_key :id
String :name, :null => false, :unique => true
validate do
presence :name,
name: :presence_name
end
end
end
down do
extension(:constraint_validations)
drop_table(:users)
end
end
class User < Sequel::Model
end
I think, it's normal. Don't worry.
I have implemented validations in a dependent manner, like if start_date format is invalid so i don't want to run other validation on start_date.
validates_format_of :available_start_date, :with => /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}((((\-|\+){1}\d{2}:\d{2}){1})|(z{1}|Z{1}))$/, :message => "must be in the following format: 2011-08-25T00:00:00-04:00"
This checks for a specific format and then i have custom validation methods called from which should run later.
def validate
super
check_offer_dates
end
I have used self.errors["start_date"] to check if the error object contains errors, it should skip the other validations on same parameter if it's not empty.
But the problem is def validate is called first and then the validates_format_of. How can i change this so that the flow can be achieved.
I just ran into a similar problem; this is how I fixed it using a before_save callout:
Not working (validates in wrong order - I want custom validation last):
class Entry < ActiveRecord::Base
validates_uniqueness_of :event_id, :within => :student_id
validate :validate_max_entries_for_discipline
def validate_max_entries_for_discipline
# set validation_failed based on my criteria - you'd have your regex test here
if validation_failed
errors.add(:maximum_entries, "Too many entries here")
end
end
end
Working (using before_save callout):
class Entry < ActiveRecord::Base
before_save :validate_max_entries_for_discipline!
validates_uniqueness_of :event_id, :within => :student_id
def validate_max_entries_for_discipline!
# set validation_failed based on my criteria - you'd have your regex test here
if validation_failed
errors.add(:maximum_entries, "Too many entries here")
return false
end
end
end
Note the changes:
validate_max_entries_for_discipline becomes validate_max_entries_for_discipline!
validation method now returns false on failure
validate validate_max_entries_for_discipline becomes before_save validate_max_entries_for_discipline!
I have a many-to-many relationship with a join table in my Rails application. I'm using the has_many :through idiom in my models. To keep things simple, lets call my first class Student, my second class Course, and the join table class Enrollment (which contains fields student_id and course_id). I want to make sure that a given Student is associated with a given Course at most once (i.e. the {student_id, course_id} tuple should be unique in the enrollment table).
So I have a migration a that enforces this uniqueness.
def change
add_index :enrollments, [:student_id, :course_id], :unique => true
end
In addition my model classes are defined as such:
class Student < ActiveRecord::Base
has_many :enrollments
has_many :courses, :through => :enrollment
end
class Course < ActiveRecord::Base
has_many :enrollments
has_many :students, :through => :enrollment
end
class Enrollment < ActiveRecord::Base
belongs_to :student
belongs_to :course
validates :student, :presence => true
validates :course, :presence => true
validates :student_id, :uniqueness => {:scope => :course_id}
end
In a rails console, I can do the following:
student = Student.first
course = Course.first
student.courses << course
#... succeeds
student.courses << course
#... appropriately fails and raises an ActiveRecord::RecordInvalid exception
In my RSpec test, I do the exact same thing and I get no exception with the following code:
#student.courses << #course
expect { #student.courses << #course }.to raise_error(ActiveRecord::RecordInvalid)
And so my test fails and reports:
expected ActiveRecord::RecordInvalid but nothing was raised
What's going on here? What could I be doing wrong? How do I fix it?
Rails uses model level validation, if you want strict checking for uniquiness you need to use database level - foreign keys for example. But in this case you need to catch exceptions from database connector.
This is strange because in my code (very similar to your) validation for unique raises exception.
There's a couple of things here that could be happening:
#courses has changed between uses.
#student has changed between uses.
By using let you'll protect these values from changing between expectations.
let(:course) { Course.first }
let(:student) { Student.first }
subject{ student.courses << course << course }
it { should raise_error(ActiveRecord::RecordInvalid) }
Or, there could just be something wrong with your code :)
I'm unclear on what this method actually does or when to use it.
Lets say I have these models:
Person < ...
# id, name
has_many :phone_numbers
end
PhoneNumber < ...
# id, number
belongs_to :person
validates_length_of :number, :in => 9..12
end
When I create phone numbers for a person like this:
#person = Person.find(1)
#person.phone_numbers.build(:number => "123456")
#person.phone_numbers.build(:number => "12346789012")
#person.save
The save fails because the first number wasn't valid. This is a good thing, to me. But what I don't understand is if its already validating the associated records what is the function validates_associated?
You can do has_many :phone_numbers, validate: false and the validation you're seeing wouldn't happen.
Why use validates_associated then? You might want to do validates_associated :phone_numbers, on: :create and skip validation on update (e.g. if there was already bad data in your db and you didn't want to hassle existing users about it).
There are other scenarios. has_one according to docs is validate: false by default. So you need validates_associated to change that.