All of the following validations are defined in the class scope of the model that you‘re interested in validating. They offer a more declarative way of specifying when the model is valid and when it is not. It is recommended to use these over the low-level calls to validate and validate_on_create when possible.
- condition_block?
- create!
- evaluate_condition
- validate
- validate_on_create
- validate_on_update
- validates_acceptance_of
- validates_associated
- validates_confirmation_of
- validates_each
- validates_exclusion_of
- validates_format_of
- validates_inclusion_of
- validates_length_of
- validates_numericality_of
- validates_presence_of
- validates_size_of
- validates_uniqueness_of
DEFAULT_VALIDATION_OPTIONS | = | { :on => :save, :allow_nil => false, :message => nil |
ALL_RANGE_OPTIONS | = | [ :is, :within, :in, :minimum, :maximum ].freeze |
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 254 254: def condition_block?(condition) 255: condition.respond_to?("call") && (condition.arity == 1 || condition.arity == -1) 256: end
Creates an object just like Base.create but calls save! instead of save so an exception is raised if the record is invalid.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 719 719: def create!(attributes = nil) 720: if attributes.is_a?(Array) 721: attributes.collect { |attr| create!(attr) } 722: else 723: attributes ||= {} 724: attributes.reverse_merge!(scope(:create)) if scoped?(:create) 725: 726: object = new(attributes) 727: object.save! 728: object 729: end 730: end
Determine from the given condition (whether a block, procedure, method or string) whether or not to validate the record. See validates_each.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 260 260: def evaluate_condition(condition, record) 261: case condition 262: when Symbol: record.send(condition) 263: when String: eval(condition, binding) 264: else 265: if condition_block?(condition) 266: condition.call(record) 267: else 268: raise( 269: ActiveRecordError, 270: "Validations need to be either a symbol, string (to be eval'ed), proc/method, or " + 271: "class implementing a static validation method" 272: ) 273: end 274: end 275: end
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 239 239: def validate(*methods, &block) 240: methods << block if block_given? 241: write_inheritable_set(:validate, methods) 242: end
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 244 244: def validate_on_create(*methods, &block) 245: methods << block if block_given? 246: write_inheritable_set(:validate_on_create, methods) 247: end
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 249 249: def validate_on_update(*methods, &block) 250: methods << block if block_given? 251: write_inheritable_set(:validate_on_update, methods) 252: end
Encapsulates the pattern of wanting to validate the acceptance of a terms of service check box (or similar agreement). Example:
class Person < ActiveRecord::Base validates_acceptance_of :terms_of_service validates_acceptance_of :eula, :message => "must be abided" end
The terms_of_service attribute is entirely virtual. No database column is needed. This check is performed only if terms_of_service is not nil and by default on save.
Configuration options:
- message - A custom error message (default is: "must be accepted")
- on - Specifies when this validation is active (default is :save, other options :create, :update)
- accept - Specifies value that is considered accepted. The default value is a string "1", which
makes it easy to relate to an HTML checkbox.
- if - Specifies a method, proc or string to call to determine if the validation should
occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 359 359: def validates_acceptance_of(*attr_names) 360: configuration = { :message => ActiveRecord::Errors.default_error_messages[:accepted], :on => :save, :allow_nil => true, :accept => "1" } 361: configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash) 362: 363: attr_accessor *attr_names 364: 365: validates_each(attr_names,configuration) do |record, attr_name, value| 366: record.errors.add(attr_name, configuration[:message]) unless value == configuration[:accept] 367: end 368: end
Validates whether the associated object or objects are all valid themselves. Works with any kind of association.
class Book < ActiveRecord::Base has_many :pages belongs_to :library validates_associated :pages, :library end
Warning: If, after the above definition, you then wrote:
class Page < ActiveRecord::Base belongs_to :book validates_associated :book end
…this would specify a circular dependency and cause infinite recursion.
NOTE: This validation will not fail if the association hasn‘t been assigned. If you want to ensure that the association is both present and guaranteed to be valid, you also need to use validates_presence_of.
Configuration options:
- on Specifies when this validation is active (default is :save, other options :create, :update)
- if - Specifies a method, proc or string to call to determine if the validation should
occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 669 669: def validates_associated(*attr_names) 670: configuration = { :message => ActiveRecord::Errors.default_error_messages[:invalid], :on => :save } 671: configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash) 672: 673: validates_each(attr_names, configuration) do |record, attr_name, value| 674: record.errors.add(attr_name, configuration[:message]) unless 675: (value.is_a?(Array) ? value : [value]).all? { |r| r.nil? or r.valid? } 676: end 677: end
Encapsulates the pattern of wanting to validate a password or email address field with a confirmation. Example:
Model: class Person < ActiveRecord::Base validates_confirmation_of :user_name, :password validates_confirmation_of :email_address, :message => "should match confirmation" end View: <%= password_field "person", "password" %> <%= password_field "person", "password_confirmation" %>
The person has to already have a password attribute (a column in the people table), but the password_confirmation is virtual. It exists only as an in-memory variable for validating the password. This check is performed only if password_confirmation is not nil and by default on save.
Configuration options:
- message - A custom error message (default is: "doesn‘t match confirmation")
- on - Specifies when this validation is active (default is :save, other options :create, :update)
- if - Specifies a method, proc or string to call to determine if the validation should
occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 330 330: def validates_confirmation_of(*attr_names) 331: configuration = { :message => ActiveRecord::Errors.default_error_messages[:confirmation], :on => :save } 332: configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash) 333: 334: attr_accessor *(attr_names.map { |n| "#{n}_confirmation" }) 335: 336: validates_each(attr_names, configuration) do |record, attr_name, value| 337: record.errors.add(attr_name, configuration[:message]) unless record.send("#{attr_name}_confirmation").nil? or value == record.send("#{attr_name}_confirmation") 338: end 339: end
Validates each attribute against a block.
class Person < ActiveRecord::Base validates_each :first_name, :last_name do |record, attr, value| record.errors.add attr, 'starts with z.' if value[0] == ?z end end
Options:
- on - Specifies when this validation is active (default is :save, other options :create, :update)
- allow_nil - Skip validation if attribute is nil.
- if - Specifies a method, proc or string to call to determine if the validation should
occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 291 291: def validates_each(*attrs) 292: options = attrs.last.is_a?(Hash) ? attrs.pop.symbolize_keys : {} 293: attrs = attrs.flatten 294: 295: # Declare the validation. 296: send(validation_method(options[:on] || :save)) do |record| 297: # Don't validate when there is an :if condition and that condition is false 298: unless options[:if] && !evaluate_condition(options[:if], record) 299: attrs.each do |attr| 300: value = record.send(attr) 301: next if value.nil? && options[:allow_nil] 302: yield record, attr, value 303: end 304: end 305: end 306: end
Validates that the value of the specified attribute is not in a particular enumerable object.
class Person < ActiveRecord::Base validates_exclusion_of :username, :in => %w( admin superuser ), :message => "You don't belong here" validates_exclusion_of :age, :in => 30..60, :message => "This site is only for under 30 and over 60" end
Configuration options:
- in - An enumerable object of items that the value shouldn‘t be part of
- message - Specifies a customer error message (default is: "is reserved")
- allow_nil - If set to true, skips this validation if the attribute is null (default is: false)
- if - Specifies a method, proc or string to call to determine if the validation should
occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 629 629: def validates_exclusion_of(*attr_names) 630: configuration = { :message => ActiveRecord::Errors.default_error_messages[:exclusion], :on => :save } 631: configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash) 632: 633: enum = configuration[:in] || configuration[:within] 634: 635: raise(ArgumentError, "An object with the method include? is required must be supplied as the :in option of the configuration hash") unless enum.respond_to?("include?") 636: 637: validates_each(attr_names, configuration) do |record, attr_name, value| 638: record.errors.add(attr_name, configuration[:message]) if enum.include?(value) 639: end 640: end
Validates whether the value of the specified attribute is of the correct form by matching it against the regular expression provided.
class Person < ActiveRecord::Base validates_format_of :email, :with => /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i, :on => :create end
Note: use \A and \Z to match the start and end of the string, ^ and $ match the start/end of a line.
A regular expression must be provided or else an exception will be raised.
Configuration options:
- message - A custom error message (default is: "is invalid")
- with - The regular expression used to validate the format with (note: must be supplied!)
- on Specifies when this validation is active (default is :save, other options :create, :update)
- if - Specifies a method, proc or string to call to determine if the validation should
occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 577 577: def validates_format_of(*attr_names) 578: configuration = { :message => ActiveRecord::Errors.default_error_messages[:invalid], :on => :save, :with => nil } 579: configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash) 580: 581: raise(ArgumentError, "A regular expression must be supplied as the :with option of the configuration hash") unless configuration[:with].is_a?(Regexp) 582: 583: validates_each(attr_names, configuration) do |record, attr_name, value| 584: record.errors.add(attr_name, configuration[:message]) unless value.to_s =~ configuration[:with] 585: end 586: end
Validates whether the value of the specified attribute is available in a particular enumerable object.
class Person < ActiveRecord::Base validates_inclusion_of :gender, :in=>%w( m f ), :message=>"woah! what are you then!??!!" validates_inclusion_of :age, :in=>0..99 end
Configuration options:
- in - An enumerable object of available items
- message - Specifies a customer error message (default is: "is not included in the list")
- allow_nil - If set to true, skips this validation if the attribute is null (default is: false)
- if - Specifies a method, proc or string to call to determine if the validation should
occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 602 602: def validates_inclusion_of(*attr_names) 603: configuration = { :message => ActiveRecord::Errors.default_error_messages[:inclusion], :on => :save } 604: configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash) 605: 606: enum = configuration[:in] || configuration[:within] 607: 608: raise(ArgumentError, "An object with the method include? is required must be supplied as the :in option of the configuration hash") unless enum.respond_to?("include?") 609: 610: validates_each(attr_names, configuration) do |record, attr_name, value| 611: record.errors.add(attr_name, configuration[:message]) unless enum.include?(value) 612: end 613: end
Validates that the specified attribute matches the length restrictions supplied. Only one option can be used at a time:
class Person < ActiveRecord::Base validates_length_of :first_name, :maximum=>30 validates_length_of :last_name, :maximum=>30, :message=>"less than %d if you don't mind" validates_length_of :fax, :in => 7..32, :allow_nil => true validates_length_of :user_name, :within => 6..20, :too_long => "pick a shorter name", :too_short => "pick a longer name" validates_length_of :fav_bra_size, :minimum=>1, :too_short=>"please enter at least %d character" validates_length_of :smurf_leader, :is=>4, :message=>"papa is spelled with %d characters... don't play me." end
Configuration options:
- minimum - The minimum size of the attribute
- maximum - The maximum size of the attribute
- is - The exact size of the attribute
- within - A range specifying the minimum and maximum size of the attribute
- in - A synonym(or alias) for :within
- allow_nil - Attribute may be nil; skip validation.
- too_long - The error message if the attribute goes over the maximum (default is: "is too long (maximum is %d characters)")
- too_short - The error message if the attribute goes under the minimum (default is: "is too short (min is %d characters)")
- wrong_length - The error message if using the :is method and the attribute is the wrong size (default is: "is the wrong length (should be %d characters)")
- message - The error message to use for a :minimum, :maximum, or :is violation. An alias of the appropriate too_long/too_short/wrong_length message
- on - Specifies when this validation is active (default is :save, other options :create, :update)
- if - Specifies a method, proc or string to call to determine if the validation should
occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 442 442: def validates_length_of(*attrs) 443: # Merge given options with defaults. 444: options = { 445: :too_long => ActiveRecord::Errors.default_error_messages[:too_long], 446: :too_short => ActiveRecord::Errors.default_error_messages[:too_short], 447: :wrong_length => ActiveRecord::Errors.default_error_messages[:wrong_length] 448: }.merge(DEFAULT_VALIDATION_OPTIONS) 449: options.update(attrs.pop.symbolize_keys) if attrs.last.is_a?(Hash) 450: 451: # Ensure that one and only one range option is specified. 452: range_options = ALL_RANGE_OPTIONS & options.keys 453: case range_options.size 454: when 0 455: raise ArgumentError, 'Range unspecified. Specify the :within, :maximum, :minimum, or :is option.' 456: when 1 457: # Valid number of options; do nothing. 458: else 459: raise ArgumentError, 'Too many range options specified. Choose only one.' 460: end 461: 462: # Get range option and value. 463: option = range_options.first 464: option_value = options[range_options.first] 465: 466: case option 467: when :within, :in 468: raise ArgumentError, ":#{option} must be a Range" unless option_value.is_a?(Range) 469: 470: too_short = options[:too_short] % option_value.begin 471: too_long = options[:too_long] % option_value.end 472: 473: validates_each(attrs, options) do |record, attr, value| 474: if value.nil? or value.split(//).size < option_value.begin 475: record.errors.add(attr, too_short) 476: elsif value.split(//).size > option_value.end 477: record.errors.add(attr, too_long) 478: end 479: end 480: when :is, :minimum, :maximum 481: raise ArgumentError, ":#{option} must be a nonnegative Integer" unless option_value.is_a?(Integer) and option_value >= 0 482: 483: # Declare different validations per option. 484: validity_checks = { :is => "==", :minimum => ">=", :maximum => "<=" } 485: message_options = { :is => :wrong_length, :minimum => :too_short, :maximum => :too_long } 486: 487: message = (options[:message] || options[message_options[option]]) % option_value 488: 489: validates_each(attrs, options) do |record, attr, value| 490: if value.kind_of?(String) 491: record.errors.add(attr, message) unless !value.nil? and value.split(//).size.method(validity_checks[option])[option_value] 492: else 493: record.errors.add(attr, message) unless !value.nil? and value.size.method(validity_checks[option])[option_value] 494: end 495: end 496: end 497: end
Validates whether the value of the specified attribute is numeric by trying to convert it to a float with Kernel.Float (if integer is false) or applying it to the regular expression /\A[+\-]?\d+\Z/ (if integer is set to true).
class Person < ActiveRecord::Base validates_numericality_of :value, :on => :create end
Configuration options:
- message - A custom error message (default is: "is not a number")
- on Specifies when this validation is active (default is :save, other options :create, :update)
- only_integer Specifies whether the value has to be an integer, e.g. an integral value (default is false)
- allow_nil Skip validation if attribute is nil (default is false). Notice that for fixnum and float columns empty strings are converted to nil
- if - Specifies a method, proc or string to call to determine if the validation should
occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 695 695: def validates_numericality_of(*attr_names) 696: configuration = { :message => ActiveRecord::Errors.default_error_messages[:not_a_number], :on => :save, 697: :only_integer => false, :allow_nil => false } 698: configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash) 699: 700: if configuration[:only_integer] 701: validates_each(attr_names,configuration) do |record, attr_name,value| 702: record.errors.add(attr_name, configuration[:message]) unless record.send("#{attr_name}_before_type_cast").to_s =~ /\A[+-]?\d+\Z/ 703: end 704: else 705: validates_each(attr_names,configuration) do |record, attr_name,value| 706: next if configuration[:allow_nil] and record.send("#{attr_name}_before_type_cast").nil? 707: begin 708: Kernel.Float(record.send("#{attr_name}_before_type_cast").to_s) 709: rescue ArgumentError, TypeError 710: record.errors.add(attr_name, configuration[:message]) 711: end 712: end 713: end 714: end
Validates that the specified attributes are not blank (as defined by Object#blank?). Happens by default on save. Example:
class Person < ActiveRecord::Base validates_presence_of :first_name end
The first_name attribute must be in the object and it cannot be blank.
If you want to validate the presence of a boolean field (where the real values are true and false), you will want to use validates_inclusion_of :field_name, :in => [true, false] This is due to the way Object#blank? handles boolean values. false.blank? # => true
Configuration options:
- message - A custom error message (default is: "can‘t be blank")
- on - Specifies when this validation is active (default is :save, other options :create, :update)
- if - Specifies a method, proc or string to call to determine if the validation should
occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
Warning
Validate the presence of the foreign key, not the instance variable itself. Do this:
validate_presence_of :invoice_id
Not this:
validate_presence_of :invoice
If you validate the presence of the associated object, you will get failures on saves when both the parent object and the child object are new.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 400 400: def validates_presence_of(*attr_names) 401: configuration = { :message => ActiveRecord::Errors.default_error_messages[:blank], :on => :save } 402: configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash) 403: 404: # can't use validates_each here, because it cannot cope with nonexistent attributes, 405: # while errors.add_on_empty can 406: attr_names.each do |attr_name| 407: send(validation_method(configuration[:on])) do |record| 408: unless configuration[:if] and not evaluate_condition(configuration[:if], record) 409: record.errors.add_on_blank(attr_name,configuration[:message]) 410: end 411: end 412: end 413: end
Alias for validates_length_of
Validates whether the value of the specified attributes are unique across the system. Useful for making sure that only one user can be named "davidhh".
class Person < ActiveRecord::Base validates_uniqueness_of :user_name, :scope => :account_id end
It can also validate whether the value of the specified attributes are unique based on multiple scope parameters. For example, making sure that a teacher can only be on the schedule once per semester for a particular class.
class TeacherSchedule < ActiveRecord::Base validates_uniqueness_of :teacher_id, :scope => [:semester_id, :class_id] end
When the record is created, a check is performed to make sure that no record exists in the database with the given value for the specified attribute (that maps to a column). When the record is updated, the same check is made but disregarding the record itself.
Configuration options:
- message - Specifies a custom error message (default is: "has already been taken")
- scope - One or more columns by which to limit the scope of the uniquness constraint.
- case_sensitive - Looks for an exact match. Ignored by non-text columns (true by default).
- allow_nil - If set to true, skips this validation if the attribute is null (default is: false)
- if - Specifies a method, proc or string to call to determine if the validation should
occur (e.g. :if => :allow_validation, or :if => Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to a true or false value.
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# File vendor/rails/activerecord/lib/active_record/validations.rb, line 528 528: def validates_uniqueness_of(*attr_names) 529: configuration = { :message => ActiveRecord::Errors.default_error_messages[:taken], :case_sensitive => true } 530: configuration.update(attr_names.pop) if attr_names.last.is_a?(Hash) 531: 532: validates_each(attr_names,configuration) do |record, attr_name, value| 533: if value.nil? || (configuration[:case_sensitive] || !columns_hash[attr_name.to_s].text?) 534: condition_sql = "#{record.class.table_name}.#{attr_name} #{attribute_condition(value)}" 535: condition_params = [value] 536: else 537: condition_sql = "LOWER(#{record.class.table_name}.#{attr_name}) #{attribute_condition(value)}" 538: condition_params = [value.downcase] 539: end 540: if scope = configuration[:scope] 541: Array(scope).map do |scope_item| 542: scope_value = record.send(scope_item) 543: condition_sql << " AND #{record.class.table_name}.#{scope_item} #{attribute_condition(scope_value)}" 544: condition_params << scope_value 545: end 546: end 547: unless record.new_record? 548: condition_sql << " AND #{record.class.table_name}.#{record.class.primary_key} <> ?" 549: condition_params << record.send(:id) 550: end 551: if record.class.find(:first, :conditions => [condition_sql, *condition_params]) 552: record.errors.add(attr_name, configuration[:message]) 553: end 554: end 555: end