Class: Ward::DSL::ValidationBuilder

Inherits:
Support::BasicObject
Defined in:
lib/ward/dsl/validation_builder.rb

Overview

Creates a single Validator. Any message received which doesn’t correspond with a matcher will be assumed to be part of the context.

Examples:


# Builds a validation whose context is "author.name" and uses the
# EqualTo matcher to ensure that the "author.name" is "Michel Scarn".

ValidationBuilder.new.author.name.is.equal_to('Michael Scarn')

Instance Method Summary collapse

Methods inherited from Support::BasicObject

const_missing

Constructor Details

#initialize ⇒ ValidationBuilder

Creates a new ValidationBuilder instance.



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# File 'lib/ward/dsl/validation_builder.rb', line 17

def initialize
  @context = Ward::ContextChain.new
  @matcher, @message, @scenarios, @negative = nil, nil, nil, false
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args, &block) ⇒ Ward::DSL::ValidatorBuilder

Provides the DSL.

Will take the given message and use it to customise the matcher (if one is set), set a matcher, or extend the context.

Returns:

  • (Ward::DSL::ValidatorBuilder) —

    Returns self.



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# File 'lib/ward/dsl/validation_builder.rb', line 149

def method_missing(method, *args, &block)
  # I'd normally shy away from using method_missing, but there's no
  # good alternative here since a user may register their own matchers
  # later in the load process.

  if @matcher
    @matcher.__send__(method, *args, &block)
  elsif Ward::Matchers.matchers.has_key?(method)
    @matcher = Ward::Matchers.matchers[method].new(*args, &block)
  elsif method.to_s =~ /\?$/
    @matcher = Ward::Matchers::Predicate.new(method, *args, &block)
  else
    attribute(method, *args, &block)
  end

  self
end

Instance Method Details

#attribute(attribute, *args, &block) ⇒ Ward::DSL::ValidatorBuilder

Adds an attribute to the context chain.

Useful your classes have attribute which you want to validate, and their name conflicts with a method on the validator DSL (e.g. “message”).

Parameters:

  • attribute (Symbol) —

    The attribute to be validated.

Returns:

  • (Ward::DSL::ValidatorBuilder) —

    Returns self.



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# File 'lib/ward/dsl/validation_builder.rb', line 108

def attribute(attribute, *args, &block)
  @context << Ward::Context.new(attribute, *args, &block)
  self
end

#context(name) ⇒ Object

Sets the name to be used for the context in error messages.

When Ward generates error messages for you, it determines the ‘context name’ by joining the method names; for example ‘name.length’ becomes ‘name length’.

This isn’t much use if you want to support languages other than English in your application, so the ‘context’ method allows you to set a custom string to be used. You may provide a String, in which case it will be used literally, a Hash of language => String, or a Symbol identifying a string to be used from a language file.

See the localisation documentation for more examples.



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# File 'lib/ward/dsl/validation_builder.rb', line 76

def context(name)
  @context_name = name
  self
end

#is(*args) ⇒ Ward::DSL::ValidatorBuilder

Set this as a positive expectation. Can be omitted.

Examples:

object.name.is.blank

Returns:

  • (Ward::DSL::ValidatorBuilder) —

    Returns self.



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# File 'lib/ward/dsl/validation_builder.rb', line 121

def is(*args)
  equal_to(*args) unless args.empty?
  self
end

#is_not(*args) ⇒ Ward::DSL::ValidatorBuilder Also known as: does_not

Set this as a negative expectation.

Examples:

object.name.is_not.blank

Returns:

  • (Ward::DSL::ValidatorBuilder) —

    Returns self.



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# File 'lib/ward/dsl/validation_builder.rb', line 134

def is_not(*args)
  @negative = true
  is(*args)
end

#message(message) ⇒ Ward::DSL::ValidatorBuilder

Sets the error message to be used if the validation fails.

This can be one of three possibilities:

* A Hash. If the matcher used returns a different error state in
  order to provide more details about what failed (such as the Has
  matcher), you may provide a hash with custom error messages for
  each error state.

* A String which will be used whenever the validation fails,
  regardless of what went wrong.

* nil (default). The validation will use the default error message
  for the matcher.

Examples:

Setting an explicit error message.


validate do |person|
  person.name.is.present.message('You must enter a name!')
end

Setting an explicit error message with a Hash.


validate do |person|
  person.name.length.is(1..50).message(
    :too_short => "Your name must be at least 1 character long",
    :too_long  => "That's an interesting name!"
  )
end

Parameters:

  • message (Hash{Symbol => String}, String, nil)

Returns:

  • (Ward::DSL::ValidatorBuilder) —

    Returns self.



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# File 'lib/ward/dsl/validation_builder.rb', line 57

def message(message)
  @message = message
  self
end

#scenarios(*scenarios) ⇒ Ward::DSL::ValidatorBuilder Also known as: scenario

Sets the scenarios under which the built validator should run.

Parameters:

  • scenarios (Symbol, ...) —

    The scenarios as Symbols.

Returns:

  • (Ward::DSL::ValidatorBuilder) —

    Returns self.



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# File 'lib/ward/dsl/validation_builder.rb', line 89

def scenarios(*scenarios)
  @scenarios = scenarios.flatten
  self
end

#to_validator ⇒ Ward::Validator

TODO:

More descriptive error messages.

Converts the builder to a Validator instance.

Returns:

Raises:

  • (IncompleteValidation) —

    An IncompleteValidationError will be raised if builder does not have all of the needed information in order to create the necessary validation (for example, if no matcher has been set).



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# File 'lib/ward/dsl/validation_builder.rb', line 179

def to_validator
  raise Ward::IncompleteValidator,
    'Validator was missing a matcher' if @matcher.nil?

  Ward::Validator.new(@context, @matcher, :message => @message,
    :scenarios => @scenarios, :negative => @negative,
    :context_name => @context_name)
end