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Add support for nested object forms to ActiveRecord and the helpers i…

…n ActionPack

Signed-Off-By: Michael Koziarski <michael@koziarski.com>

[#1202 state:committed]
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1 parent a02d752 commit ec8f04584479aff895b0b511a7ba1e9d33f84067 @alloy alloy committed with NZKoz Feb 1, 2009
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@@ -1,5 +1,17 @@
*2.3.0 [Edge]*
+* Make the form_for and fields_for helpers support the new Active Record nested update options. #1202 [Eloy Duran]
+
+ <% form_for @person do |person_form| %>
+ ...
+ <% person_form.fields_for :projects do |project_fields| %>
+ <% if project_fields.object.active? %>
+ Name: <%= project_fields.text_field :name %>
+ <% end %>
+ <% end %>
+ <% end %>
+
+
* Added grouped_options_for_select helper method for wrapping option tags in optgroups. #977 [Jon Crawford]
* Implement HTTP Digest authentication. #1230 [Gregg Kellogg, Pratik Naik] Example :
@@ -269,10 +269,12 @@ def apply_form_for_options!(object_or_array, options) #:nodoc:
options[:url] ||= polymorphic_path(object_or_array)
end
- # Creates a scope around a specific model object like form_for, but doesn't create the form tags themselves. This makes
- # fields_for suitable for specifying additional model objects in the same form:
+ # Creates a scope around a specific model object like form_for, but
+ # doesn't create the form tags themselves. This makes fields_for suitable
+ # for specifying additional model objects in the same form.
+ #
+ # === Generic Examples
#
- # ==== Examples
# <% form_for @person, :url => { :action => "update" } do |person_form| %>
# First name: <%= person_form.text_field :first_name %>
# Last name : <%= person_form.text_field :last_name %>
@@ -282,20 +284,166 @@ def apply_form_for_options!(object_or_array, options) #:nodoc:
# <% end %>
# <% end %>
#
- # ...or if you have an object that needs to be represented as a different parameter, like a Client that acts as a Person:
+ # ...or if you have an object that needs to be represented as a different
+ # parameter, like a Client that acts as a Person:
#
# <% fields_for :person, @client do |permission_fields| %>
# Admin?: <%= permission_fields.check_box :admin %>
# <% end %>
#
- # ...or if you don't have an object, just a name of the parameter
+ # ...or if you don't have an object, just a name of the parameter:
#
# <% fields_for :person do |permission_fields| %>
# Admin?: <%= permission_fields.check_box :admin %>
# <% end %>
#
- # Note: This also works for the methods in FormOptionHelper and DateHelper that are designed to work with an object as base,
- # like FormOptionHelper#collection_select and DateHelper#datetime_select.
+ # Note: This also works for the methods in FormOptionHelper and
+ # DateHelper that are designed to work with an object as base, like
+ # FormOptionHelper#collection_select and DateHelper#datetime_select.
+ #
+ # === Nested Attributes Examples
+ #
+ # When the object belonging to the current scope has a nested attribute
+ # writer for a certain attribute, fields_for will yield a new scope
+ # for that attribute. This allows you to create forms that set or change
+ # the attributes of a parent object and its associations in one go.
+ #
+ # Nested attribute writers are normal setter methods named after an
+ # association. The most common way of defining these writers is either
+ # with +accepts_nested_attributes_for+ in a model definition or by
+ # defining a method with the proper name. For example: the attribute
+ # writer for the association <tt>:address</tt> is called
+ # <tt>address_attributes=</tt>.
+ #
+ # Whether a one-to-one or one-to-many style form builder will be yielded
+ # depends on whether the normal reader method returns a _single_ object
+ # or an _array_ of objects.
+ #
+ # ==== One-to-one
+ #
+ # Consider a Person class which returns a _single_ Address from the
+ # <tt>address</tt> reader method and responds to the
+ # <tt>address_attributes=</tt> writer method:
+ #
+ # class Person
+ # def address
+ # @address
+ # end
+ #
+ # def address_attributes=(attributes)
+ # # Process the attributes hash
+ # end
+ # end
+ #
+ # This model can now be used with a nested fields_for, like so:
+ #
+ # <% form_for @person, :url => { :action => "update" } do |person_form| %>
+ # ...
+ # <% person_form.fields_for :address do |address_fields| %>
+ # Street : <%= address_fields.text_field :street %>
+ # Zip code: <%= address_fields.text_field :zip_code %>
+ # <% end %>
+ # <% end %>
+ #
+ # When address is already an association on a Person you can use
+ # +accepts_nested_attributes_for+ to define the writer method for you:
+ #
+ # class Person < ActiveRecord::Base
+ # has_one :address
+ # accepts_nested_attributes_for :address
+ # end
+ #
+ # If you want to destroy the associated model through the form, you have
+ # to enable it first using the <tt>:allow_destroy</tt> option for
+ # +accepts_nested_attributes_for+:
+ #
+ # class Person < ActiveRecord::Base
+ # has_one :address
+ # accepts_nested_attributes_for :address, :allow_destroy => true
+ # end
+ #
+ # Now, when you use a form element with the <tt>_delete</tt> parameter,
+ # with a value that evaluates to +true+, you will destroy the associated
+ # model (eg. 1, '1', true, or 'true'):
+ #
+ # <% form_for @person, :url => { :action => "update" } do |person_form| %>
+ # ...
+ # <% person_form.fields_for :address do |address_fields| %>
+ # ...
+ # Delete: <%= address_fields.check_box :_delete %>
+ # <% end %>
+ # <% end %>
+ #
+ # ==== One-to-many
+ #
+ # Consider a Person class which returns an _array_ of Project instances
+ # from the <tt>projects</tt> reader method and responds to the
+ # <tt>projects_attributes=</tt> writer method:
+ #
+ # class Person
+ # def projects
+ # [@project1, @project2]
+ # end
+ #
+ # def projects_attributes=(attributes)
+ # # Process the attributes hash
+ # end
+ # end
+ #
+ # This model can now be used with a nested fields_for. The block given to
+ # the nested fields_for call will be repeated for each instance in the
+ # collection:
+ #
+ # <% form_for @person, :url => { :action => "update" } do |person_form| %>
+ # ...
+ # <% person_form.fields_for :projects do |project_fields| %>
+ # <% if project_fields.object.active? %>
+ # Name: <%= project_fields.text_field :name %>
+ # <% end %>
+ # <% end %>
+ # <% end %>
+ #
+ # It's also possible to specify the instance to be used:
+ #
+ # <% form_for @person, :url => { :action => "update" } do |person_form| %>
+ # ...
+ # <% @person.projects.each do |project| %>
+ # <% if project.active? %>
+ # <% person_form.fields_for :projects, project do |project_fields| %>
+ # Name: <%= project_fields.text_field :name %>
+ # <% end %>
+ # <% end %>
+ # <% end %>
+ # <% end %>
+ #
+ # When projects is already an association on Person you can use
+ # +accepts_nested_attributes_for+ to define the writer method for you:
+ #
+ # class Person < ActiveRecord::Base
+ # has_many :projects
+ # accepts_nested_attributes_for :projects
+ # end
+ #
+ # If you want to destroy any of the associated models through the
+ # form, you have to enable it first using the <tt>:allow_destroy</tt>
+ # option for +accepts_nested_attributes_for+:
+ #
+ # class Person < ActiveRecord::Base
+ # has_many :projects
+ # accepts_nested_attributes_for :projects, :allow_destroy => true
+ # end
+ #
+ # This will allow you to specify which models to destroy in the
+ # attributes hash by adding a form element for the <tt>_delete</tt>
+ # parameter with a value that evaluates to +true+
+ # (eg. 1, '1', true, or 'true'):
+ #
+ # <% form_for @person, :url => { :action => "update" } do |person_form| %>
+ # ...
+ # <% person_form.fields_for :projects do |project_fields| %>
+ # Delete: <%= project_fields.check_box :_delete %>
+ # <% end %>
+ # <% end %>
def fields_for(record_or_name_or_array, *args, &block)
raise ArgumentError, "Missing block" unless block_given?
options = args.extract_options!
@@ -760,7 +908,11 @@ def fields_for(record_or_name_or_array, *args, &block)
case record_or_name_or_array
when String, Symbol
- name = "#{object_name}#{index}[#{record_or_name_or_array}]"
+ if nested_attributes_association?(record_or_name_or_array)
+ return fields_for_with_nested_attributes(record_or_name_or_array, args, block)
+ else
+ name = "#{object_name}#{index}[#{record_or_name_or_array}]"
+ end
when Array
object = record_or_name_or_array.last
name = "#{object_name}#{index}[#{ActionController::RecordIdentifier.singular_class_name(object)}]"
@@ -802,11 +954,37 @@ def submit(value = "Save changes", options = {})
def objectify_options(options)
@default_options.merge(options.merge(:object => @object))
end
+
+ def nested_attributes_association?(association_name)
+ @object.respond_to?("#{association_name}_attributes=")
+ end
+
+ def fields_for_with_nested_attributes(association_name, args, block)
+ name = "#{object_name}[#{association_name}_attributes]"
+ association = @object.send(association_name)
+
+ if association.is_a?(Array)
+ children = args.first.respond_to?(:new_record?) ? [args.first] : association
+
+ children.map do |child|
+ child_name = "#{name}[#{ child.new_record? ? new_child_id : child.id }]"
+ @template.fields_for(child_name, child, *args, &block)
+ end.join
+ else
+ @template.fields_for(name, association, *args, &block)
+ end
+ end
+
+ def new_child_id
+ value = (@child_counter ||= 1)
+ @child_counter += 1
+ "new_#{value}"
+ end
end
end
class Base
cattr_accessor :default_form_builder
self.default_form_builder = ::ActionView::Helpers::FormBuilder
end
-end
+end
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3 comments on commit ec8f045

@tamersalama

Great Feature! Thanks Guys.

I hope I’m not making a fool of myself here :)

It seems that adding the foreign key presence validation to the child instance creates a circular dependency (the child validation is done before the parent id is propagated to the child).


class Person < ActiveRecord::Base
  has_many :children
  accepts_nested_attributes_for :children
end

class Child < ActiveRecord::Base
  belongs_to :person
  
  #Validating that a toy belongs to a person
  validates_presence_of :person_id
end

  p = Person.new(:name => "Smith", :children_attributes => {"new_1" => {:name => "John"}})
  p.valid? #=> false
  p.save  #false
  p.children.first.errors.on(:person_id) #=> "can't be blank"

Is it just late or does it need a work-around?

@alloy
alloy commented on ec8f045 Feb 11, 2009

tamersalama: No your not making a fool out of yourself :)
Please file a ticket on lighthouse: http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets

@tamersalama

A ticket has been created:

http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/1943

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