Active Record 验证

class Person < ApplicationRecord
  validates :name, presence: true
end

irb> Person.new(name: "John Doe").valid?
=> true
irb> Person.new(name: nil).valid?
=> false

class Person < ApplicationRecord
end

irb> p = Person.new(name: "Jane Doe")
=> #<Person id: nil, name: "Jane Doe", created_at: nil, updated_at: nil>

irb> p.new_record?
=> true

irb> p.persisted?
=> false

irb> p.save
=> true

irb> p.new_record?
=> false

irb> p.persisted?
=> true

class Person < ApplicationRecord
  validates :name, presence: true
end

irb> Person.new(name: "John Doe").valid?
=> true
irb> Person.new(name: nil).valid?
=> false

class Person < ApplicationRecord
  validates :name, presence: true
end

irb> person = Person.new
=> #<Person id: nil, name: nil, created_at: nil, updated_at: nil>
irb> person.errors.size
=> 0

irb> person.valid?
=> false
irb> person.errors.objects.first.full_message
=> "Name can't be blank"

irb> person.save
=> false

irb> person.save!
ActiveRecord::RecordInvalid: Validation failed: Name can't be blank

irb> Person.create!
ActiveRecord::RecordInvalid: Validation failed: Name can't be blank

class Person < ApplicationRecord
  validates :name, presence: true
end

irb> new_person = Person.new
irb> new_person.errors[:name]
=> [] # no errors since validations are not run until saved
irb> new_person.errors[:name].any?
=> false

irb> create_person = Person.create
irb> create_person.errors[:name]
=> ["can't be blank"] # validation error because `name` is required
irb> create_person.errors[:name].any?
=> true

class Person < ApplicationRecord
  validate do |person|
    errors.add :name, :too_short, message: "is not long enough"
  end
end

validates :name, presence: true

validates_presence_of :name

class Person < ApplicationRecord
  validates :phone_number, :address, absence: true, if: :invited?
end

irb> person = Person.new(name: "Jane Doe", invitation_sent_at: Time.current)
irb> person.valid?
=> true # absence validation passes

class LineItem < ApplicationRecord
  belongs_to :order, optional: true
  validates :order, absence: true
end

irb> line_item = LineItem.new
irb> line_item.valid?
=> true # absence validation passes

order = Order.create
irb> line_item_with_order = LineItem.new(order: order)
irb> line_item_with_order.valid?
=> false # absence validation fails

validates :field_name, exclusion: { in: [true, false] }

class Person < ApplicationRecord
  validates :terms_of_service, acceptance: true
end

class Person < ApplicationRecord
  validates :terms_of_service, acceptance: { message: "must be agreed to" }
end

class Person < ApplicationRecord
  validates :terms_of_service, acceptance: { accept: "yes" }
  validates :eula, acceptance: { accept: ["TRUE", "accepted"] }
end

class Person < ApplicationRecord
  validates :email, confirmation: true
end

<%= text_field :person, :email %>
<%= text_field :person, :email_confirmation %>

class Person < ApplicationRecord
  validates :email, confirmation: true
  validates :email_confirmation, presence: true
end

class Person < ApplicationRecord
  validates :email, confirmation: { case_sensitive: false }
end

class Person < ApplicationRecord
  validates :email, confirmation: true
  validates :email_confirmation, presence: true, if: :email_changed?
end

class Promotion < ApplicationRecord
  validates :end_date, comparison: { greater_than: :start_date }
end

class Product < ApplicationRecord
  validates :legacy_code, format: { with: /\A[a-zA-Z]+\z/,
    message: "only allows letters" }
end

class Coffee < ApplicationRecord
  validates :size, inclusion: { in: %w(small medium large),
    message: "%{value} is not a valid size" }
end

class Account < ApplicationRecord
  validates :subdomain, exclusion: { in: %w(www us ca jp),
    message: "%{value} is reserved." }
end

class Coffee < ApplicationRecord
  validates :size, inclusion: { in: ->(coffee) { coffee.available_sizes } }

  def available_sizes
    %w(small medium large extra_large)
  end
end

class Account < ApplicationRecord
  validates :subdomain, exclusion: { in: ->(account) { account.reserved_subdomains } }

  def reserved_subdomains
    %w(www us ca jp admin)
  end
end

class Person < ApplicationRecord
  validates :name, length: { minimum: 2 }
  validates :bio, length: { maximum: 500 }
  validates :password, length: { in: 6..20 }
  validates :registration_number, length: { is: 6 }
end

class Person < ApplicationRecord
  validates :bio, length: { maximum: 1000,
    too_long: "%{count} characters is the maximum allowed" }
end

/\A[+-]?\d+\z/

class Player < ApplicationRecord
  validates :points, numericality: true
  validates :games_played, numericality: { only_integer: true }
end

class Person < ApplicationRecord
  validates :name, :login, :email, presence: true
end

person = Person.new(name: "Alice", login: "alice123", email: "alice@example.com")
person.valid?
=> true # presence validation passes

invalid_person = Person.new(name: "", login: nil, email: "bob@example.com")
invalid_person.valid?
=> false # presence validation fails

class Supplier < ApplicationRecord
  has_one :account
  validates :account, presence: true
end

irb> account = Account.create(name: "Account A")

irb> supplier = Supplier.new(account: account)
irb> supplier.valid?
=> true # presence validation passes

irb> invalid_supplier = Supplier.new
irb> invalid_supplier.valid?
=> false # presence validation fails

# Value _must_ be true or false
validates :boolean_field_name, inclusion: [true, false]
# Value _must not_ be nil, aka true or false
validates :boolean_field_name, exclusion: [nil]

class Account < ApplicationRecord
  validates :email, uniqueness: true
end

class Holiday < ApplicationRecord
  validates :name, uniqueness: { scope: :year,
    message: "should happen once per year" }
end

class Person < ApplicationRecord
  validates :name, uniqueness: { case_sensitive: false }
end

validates :name, uniqueness: { conditions: -> { where(status: "active") } }

class Library < ApplicationRecord
  has_many :books
  validates_associated :books
end

class Person < ApplicationRecord
  validates_each :name, :surname do |record, attr, value|
    record.errors.add(attr, "must start with upper case") if /\A[[:lower:]]/.match?(value)
  end
end

class AddressValidator < ActiveModel::Validator
  def validate(record)
    if record.house_number.blank?
      record.errors.add :house_number, "is required"
    end

    if record.street.blank?
      record.errors.add :street, "is required"
    end

    if record.postcode.blank?
      record.errors.add :postcode, "is required"
    end
  end
end

class Invoice < ApplicationRecord
  validates_with AddressValidator
end

def validate(record)
  if record.some_field != "acceptable"
    record.errors.add :some_field, "this field is unacceptable"
  end
end

class Person < ApplicationRecord
  validates_with MyValidator, MyOtherValidator, on: :create
end

class AddressValidator < ActiveModel::Validator
  def validate(record)
    options[:fields].each do |field|
      if record.send(field).blank?
        record.errors.add field, "is required"
      end
    end
  end
end

class Invoice < ApplicationRecord
  validates_with AddressValidator, fields: [:house_number, :street, :postcode, :country]
end

class Invoice < ApplicationRecord
  validate do |invoice|
    AddressValidator.new(invoice).validate
  end
end

class AddressValidator
  def initialize(invoice)
    @invoice = invoice
  end

  def validate
    validate_field(:house_number)
    validate_field(:street)
    validate_field(:postcode)
  end

  private
    def validate_field(field)
      if @invoice.send(field).blank?
        @invoice.errors.add field, "#{field.to_s.humanize} is required"
      end
    end
end

class Coffee < ApplicationRecord
  validates :size, inclusion: { in: %w(small medium large),
    message: "%{value} is not a valid size" }, allow_nil: true
end

irb> Coffee.create(size: nil).valid?
=> true
irb> Coffee.create(size: "mega").valid?
=> false

class Topic < ApplicationRecord
  validates :title, length: { is: 6 }, allow_blank: true
end

irb> Topic.create(title: "").valid?
=> true
irb> Topic.create(title: nil).valid?
=> true
irb> Topic.create(title: "short").valid?
=> false # 'short' is not of length 6, so validation fails even though it's not blank

class Person < ApplicationRecord
  # Hard-coded message
  validates :name, presence: { message: "must be given please" }

  # Message with dynamic attribute value. %{value} will be replaced
  # with the actual value of the attribute. %{attribute} and %{model}
  # are also available.
  validates :age, numericality: { message: "%{value} seems wrong" }
end

class Person < ApplicationRecord
  validates :username,
    uniqueness: {
      # object = person object being validated
      # data = { model: "Person", attribute: "Username", value: <username> }
      message: ->(object, data) do
        "Hey #{object.name}, #{data[:value]} is already taken."
      end
    }
end

class Person < ApplicationRecord
  # it will be possible to update email with a duplicated value
  validates :email, uniqueness: true, on: :create

  # it will be possible to create the record with a non-numerical age
  validates :age, numericality: true, on: :update

  # the default (validates on both create and update)
  validates :name, presence: true
end

class Person < ApplicationRecord
  validates :email, uniqueness: true, on: :account_setup
  validates :age, numericality: true, on: :account_setup
end

irb> person = Person.new(age: 'thirty-three')
irb> person.valid?
=> true
irb> person.valid?(:account_setup)
=> false
irb> person.errors.messages
=> {:email=>["has already been taken"], :age=>["is not a number"]}

class Book
  include ActiveModel::Validations

  validates :title, presence: true, on: [:update, :ensure_title]
end

irb> book = Book.new(title: nil)
irb> book.valid?
=> true
irb> book.valid?(:ensure_title)
=> false
irb> book.errors.messages
=> {:title=>["can't be blank"]}

class Person < ApplicationRecord
  validates :email, uniqueness: true, on: :account_setup
  validates :age, numericality: true, on: :account_setup
  validates :name, presence: true
end

irb> person = Person.new
irb> person.valid?(:account_setup)
=> false
irb> person.errors.messages
=> {:email=>["has already been taken"], :age=>["is not a number"], :name=>["can't be blank"]}

class Order < ApplicationRecord
  validates :card_number, presence: true, if: :paid_with_card?

  def paid_with_card?
    payment_type == "card"
  end
end

class Account < ApplicationRecord
  validates :password, confirmation: true,
    unless: Proc.new { |a| a.password.blank? }
end

validates :password, confirmation: true, unless: -> { password.blank? }

class User < ApplicationRecord
  with_options if: :is_admin? do |admin|
    admin.validates :password, length: { minimum: 10 }
    admin.validates :email, presence: true
  end
end

class Computer < ApplicationRecord
  validates :mouse, presence: true,
                    if: [Proc.new { |c| c.market.retail? }, :desktop?],
                    unless: Proc.new { |c| c.trackpad.present? }
end

class Person < ApplicationRecord
  validates :name, presence: { strict: true }
end

irb> Person.new.valid?
=> ActiveModel::StrictValidationFailed: Name can't be blank

class Person < ApplicationRecord
  validates :token, presence: true, uniqueness: true, strict: TokenGenerationException
end

irb> Person.new.valid?
=> TokenGenerationException: Token can't be blank

class Person < ApplicationRecord
  validates :name, presence: true, on: :create
  validates :email, format: URI::MailTo::EMAIL_REGEXP
  validates_with MyOtherValidator, strict: true
end

irb> Person.validators
#=> [#<ActiveRecord::Validations::PresenceValidator:0x10b2f2158
      @attributes=[:name], @options={:on=>:create}>,
     #<MyOtherValidatorValidator:0x10b2f17d0
      @attributes=[:name], @options={:strict=>true}>,
     #<ActiveModel::Validations::FormatValidator:0x10b2f0f10
      @attributes=[:email],
      @options={:with=>URI::MailTo::EMAIL_REGEXP}>]
     #<MyOtherValidator:0x10b2f0948 @options={:strict=>true}>]

irb> Person.validators_on(:name)
#=> [#<ActiveModel::Validations::PresenceValidator:0x10b2f2158
      @attributes=[:name], @options={on: :create}>]

class MyValidator < ActiveModel::Validator
  def validate(record)
    unless record.name.start_with? "X"
      record.errors.add :name, "Provide a name starting with X, please!"
    end
  end
end

class Person < ApplicationRecord
  validates_with MyValidator
end

class EmailValidator < ActiveModel::EachValidator
  def validate_each(record, attribute, value)
    unless URI::MailTo::EMAIL_REGEXP.match?(value)
      record.errors.add attribute, (options[:message] || "is not an email")
    end
  end
end

class Person < ApplicationRecord
  validates :email, presence: true, email: true
end

class Invoice < ApplicationRecord
  validate :expiration_date_cannot_be_in_the_past,
    :discount_cannot_be_greater_than_total_value

  def expiration_date_cannot_be_in_the_past
    if expiration_date.present? && expiration_date < Date.today
      errors.add(:expiration_date, "can't be in the past")
    end
  end

  def discount_cannot_be_greater_than_total_value
    if discount > total_value
      errors.add(:discount, "can't be greater than total value")
    end
  end
end

class Invoice < ApplicationRecord
  validate :active_customer, on: :create

  def active_customer
    errors.add(:customer_id, "is not active") unless customer.active?
  end
end

class User < ApplicationRecord
  validate :personal_information, on: :personal_info
  validate :contact_information, on: :contact_info
  validate :location_information, on: :location_info

  private
    def personal_information
      errors.add(:base, "Name must be present") if first_name.blank?
      errors.add(:base, "Age must be at least 18") if age && age < 18
    end

    def contact_information
      errors.add(:base, "Email must be present") if email.blank?
      errors.add(:base, "Phone number must be present") if phone.blank?
    end

    def location_information
      errors.add(:base, "Address must be present") if address.blank?
      errors.add(:base, "City must be present") if city.blank?
    end
end

irb> user = User.new(name: "John Doe", age: 17, email: "jane@example.com", phone: "1234567890", address: "123 Main St")
irb> user.valid?(:personal_info) # => false
irb> user.valid?(:contact_info) # => true
irb> user.valid?(:location_info) # => false

irb> user = User.new(name: "John Doe", age: 17, email: "jane@example.com", phone: "1234567890", address: "123 Main St")
irb> user.save(context: :personal_info) # => false
irb> user.save(context: :contact_info) # => true
irb> user.save(context: :location_info) # => false

class Person < ApplicationRecord
  validates :name, presence: true, length: { minimum: 3 }
end

irb> person = Person.new
irb> person.valid?
=> false
irb> person.errors.full_messages
=> ["Name can't be blank", "Name is too short (minimum is 3 characters)"]

irb> person = Person.new(name: "John Doe")
irb> person.valid?
=> true
irb> person.errors.full_messages
=> []

irb> person = Person.new
irb> person.valid?
=> false
irb> person.errors.first.details
=> {:error=>:too_short, :count=>3}

class Person < ApplicationRecord
  validates :name, presence: true, length: { minimum: 3 }
end

irb> person = Person.new(name: "John Doe")
irb> person.valid?
=> true
irb> person.errors[:name]
=> []

irb> person = Person.new(name: "JD")
irb> person.valid?
=> false
irb> person.errors[:name]
=> ["is too short (minimum is 3 characters)"]

irb> person = Person.new
irb> person.valid?
=> false
irb> person.errors[:name]
=> ["can't be blank", "is too short (minimum is 3 characters)"]

class Person < ApplicationRecord
  validates :name, presence: true, length: { minimum: 3 }
end

irb> person = Person.new
irb> person.valid?
=> false

irb> person.errors.where(:name)
=> [ ... ] # all errors for :name attribute

irb> person.errors.where(:name, :too_short)
=> [ ... ] # :too_short errors for :name attribute

irb> person = Person.new
irb> person.valid?
=> false

irb> person.errors.where(:name, :too_short, minimum: 3)
=> [ ... ] # all name errors being too short and minimum is 3

irb> error = person.errors.where(:name).last

irb> error.attribute
=> :name
irb> error.type
=> :too_short
irb> error.options[:count]
=> 3

irb> error.message
=> "is too short (minimum is 3 characters)"
irb> error.full_message
=> "Name is too short (minimum is 3 characters)"

class Person < ApplicationRecord
  validate do |person|
    errors.add :name, :too_plain, message: "is not cool enough"
  end
end

irb> person = Person.new
irb> person.errors.where(:name).first.type
=> :too_plain
irb> person.errors.where(:name).first.full_message
=> "Name is not cool enough"

class Person < ApplicationRecord
  validate do |person|
    errors.add :base, :invalid, message: "This person is invalid because ..."
  end
end

irb> person = Person.new
irb> person.errors.where(:base).first.full_message
=> "This person is invalid because ..."

class Person < ApplicationRecord
  validates :name, presence: true, length: { minimum: 3 }
end

irb> person = Person.new
irb> person.valid?
=> false
irb> person.errors.size
=> 2

irb> person = Person.new(name: "Andrea", email: "andrea@example.com")
irb> person.valid?
=> true
irb> person.errors.size
=> 0

class Person < ApplicationRecord
  validates :name, presence: true, length: { minimum: 3 }
end

irb> person = Person.new
irb> person.valid?
=> false
irb> person.errors.empty?
=> false

irb> person.errors.clear
irb> person.errors.empty?
=> true

irb> person.save
=> false

irb> person.errors.empty?
=> false

<% if @article.errors.any? %>
  <div id="error_explanation">
    <h2><%= pluralize(@article.errors.count, "error") %> prohibited this article from being saved:</h2>

    <ul>
      <% @article.errors.each do |error| %>
        <li><%= error.full_message %></li>
      <% end %>
    </ul>
  </div>
<% end %>

<div class="field_with_errors">
  <input id="article_title" name="article[title]" size="30" type="text" value="">
</div>

.field_with_errors {
  padding: 2px;
  background-color: red;
  display: table;
}

config.action_view.field_error_proc = Proc.new { |html_tag, instance| content_tag :div, html_tag, class: "field_with_errors" }