Class: ActionView::Helpers::FormBuilder

Inherits:
Object
  • Object
show all
Includes:
ModelNaming
Defined in:
lib/action_view/helpers/form_helper.rb,
lib/action_view/helpers/date_helper.rb,
lib/action_view/helpers/form_options_helper.rb

Overview

A FormBuilder object is associated with a particular model object and allows you to generate fields associated with the model object. The FormBuilder object is yielded when using form_for or fields_for. For example:

<%= form_for @person do |person_form| %>
  Name: <%= person_form.text_field :name %>
  Admin: <%= person_form.check_box :admin %>
<% end %>

In the above block, a FormBuilder object is yielded as the person_form variable. This allows you to generate the text_field and check_box fields by specifying their eponymous methods, which modify the underlying template and associates the @person model object with the form.

The FormBuilder object can be thought of as serving as a proxy for the methods in the FormHelper module. This class, however, allows you to call methods with the model object you are building the form for.

You can create your own custom FormBuilder templates by subclassing this class. For example:

class MyFormBuilder < ActionView::Helpers::FormBuilder
  def div_radio_button(method, tag_value, options = {})
    @template.content_tag(:div,
      @template.radio_button(
        @object_name, method, tag_value, objectify_options(options)
      )
    )
  end
end

The above code creates a new method div_radio_button which wraps a div around the new radio button. Note that when options are passed in, you must call objectify_options in order for the model object to get correctly passed to the method. If objectify_options is not called, then the newly created helper will not be linked back to the model.

The div_radio_button code from above can now be used as follows:

<%= form_for @person, :builder => MyFormBuilder do |f| %>
  I am a child: <%= f.div_radio_button(:admin, "child") %>
  I am an adult: <%= f.div_radio_button(:admin, "adult") %>
<% end -%>

The standard set of helper methods for form building are located in the field_helpers class attribute.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from ModelNaming

#convert_to_model, #model_name_from_record_or_class

Constructor Details

#initialize(object_name, object, template, options) ⇒ FormBuilder

Returns a new instance of FormBuilder.



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# File 'lib/action_view/helpers/form_helper.rb', line 1695

def initialize(object_name, object, template, options)
  @nested_child_index = {}
  @object_name, @object, @template, @options = object_name, object, template, options
  @default_options = @options ? @options.slice(:index, :namespace, :skip_default_ids, :allow_method_names_outside_object) : {}
  @default_html_options = @default_options.except(:skip_default_ids, :allow_method_names_outside_object)

  convert_to_legacy_options(@options)

  if @object_name&.end_with?("[]")
    if (object ||= @template.instance_variable_get("@#{@object_name[0..-3]}")) && object.respond_to?(:to_param)
      @auto_index = object.to_param
    else
      raise ArgumentError, "object[] naming but object param and @object var don't exist or don't respond to to_param: #{object.inspect}"
    end
  end

  @multipart = nil
  @index = options[:index] || options[:child_index]
end

Instance Attribute Details

#index ⇒ Object (readonly)

Returns the value of attribute index.



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# File 'lib/action_view/helpers/form_helper.rb', line 1672

def index
  @index
end

#multipart ⇒ Object Also known as: multipart?

Returns the value of attribute multipart.



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# File 'lib/action_view/helpers/form_helper.rb', line 1672

def multipart
  @multipart
end

#object ⇒ Object

Returns the value of attribute object.



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# File 'lib/action_view/helpers/form_helper.rb', line 1670

def object
  @object
end

#object_name ⇒ Object

Returns the value of attribute object_name.



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# File 'lib/action_view/helpers/form_helper.rb', line 1670

def object_name
  @object_name
end

#options ⇒ Object

Returns the value of attribute options.



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# File 'lib/action_view/helpers/form_helper.rb', line 1670

def options
  @options
end

Class Method Details

._to_partial_path ⇒ Object 



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# File 'lib/action_view/helpers/form_helper.rb', line 1683

def self._to_partial_path
  @_to_partial_path ||= name.demodulize.underscore.sub!(/_builder$/, "")
end

Instance Method Details

#button(value = nil, options = {}, &block) ⇒ Object

Add the submit button for the given form. When no value is given, it checks if the object is a new resource or not to create the proper label:

<%= form_for @post do |f| %>
  <%= f.button %>
<% end %>

In the example above, if @post is a new record, it will use “Create Post” as button label; otherwise, it uses “Update Post”.

Those labels can be customized using I18n under the helpers.submit key (the same as submit helper) and using %{model} for translation interpolation:

en:
  helpers:
    submit:
      create: "Create a %{model}"
      update: "Confirm changes to %{model}"

It also searches for a key specific to the given object:

en:
  helpers:
    submit:
      post:
        create: "Add %{model}"

Examples

button("Create post")
# => <button name='button' type='submit'>Create post</button>

button(:draft, value: true)
# => <button id="post_draft" name="post[draft]" value="true" type="submit">Create post</button>

button do
  content_tag(:strong, 'Ask me!')
end
# => <button name='button' type='submit'>
#      <strong>Ask me!</strong>
#    </button>

button do |text|
  content_tag(:strong, text)
end
# => <button name='button' type='submit'>
#      <strong>Create post</strong>
#    </button>

button(:draft, value: true) do
  content_tag(:strong, "Save as draft")
end
# =>  <button id="post_draft" name="post[draft]" value="true" type="submit">
#       <strong>Save as draft</strong>
#     </button>



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# File 'lib/action_view/helpers/form_helper.rb', line 2609

def button(value = nil, options = {}, &block)
  case value
  when Hash
    value, options = nil, value
  when Symbol
    value, options = nil, { name: field_name(value), id: field_id(value) }.merge!(options.to_h)
  end
  value ||= submit_default_value

  if block_given?
    value = @template.capture { yield(value) }
  end

  formmethod = options[:formmethod]
  if formmethod.present? && !/post|get/i.match?(formmethod) && !options.key?(:name) && !options.key?(:value)
    options.merge! formmethod: :post, name: "_method", value: formmethod
  end

  @template.button_tag(value, options)
end

#check_box(method, options = {}, checked_value = "1", unchecked_value = "0") ⇒ Object

Returns a checkbox tag tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object). This object must be an instance object (@object) and not a local object. It’s intended that method returns an integer and if that integer is above zero, then the checkbox is checked. Additional options on the input tag can be passed as a hash with options. The checked_value defaults to 1 while the default unchecked_value is set to 0 which is convenient for boolean values.

Options

  • Any standard HTML attributes for the tag can be passed in, for example :class.

  • :checked - true or false forces the state of the checkbox to be checked or not.

  • :include_hidden - If set to false, the auxiliary hidden field described below will not be generated.

Gotcha

The HTML specification says unchecked check boxes are not successful, and thus web browsers do not send them. Unfortunately this introduces a gotcha: if an Invoice model has a paid flag, and in the form that edits a paid invoice the user unchecks its check box, no paid parameter is sent. So, any mass-assignment idiom like

@invoice.update(params[:invoice])

wouldn’t update the flag.

To prevent this the helper generates an auxiliary hidden field before every check box. The hidden field has the same name and its attributes mimic an unchecked check box.

This way, the client either sends only the hidden field (representing the check box is unchecked), or both fields. Since the HTML specification says key/value pairs have to be sent in the same order they appear in the form, and parameters extraction gets the last occurrence of any repeated key in the query string, that works for ordinary forms.

Unfortunately that workaround does not work when the check box goes within an array-like parameter, as in

<%= fields_for "project[invoice_attributes][]", invoice, index: nil do |form| %>
  <%= form.check_box :paid %>
  ...
<% end %>

because parameter name repetition is precisely what Rails seeks to distinguish the elements of the array. For each item with a checked check box you get an extra ghost item with only that attribute, assigned to “0”.

In that case it is preferable to either use check_box_tag or to use hashes instead of arrays.

Examples

# Let's say that @post.validated? is 1:
check_box("validated")
# => <input name="post[validated]" type="hidden" value="0" />
#    <input checked="checked" type="checkbox" id="post_validated" name="post[validated]" value="1" />

# Let's say that @puppy.gooddog is "no":
check_box("gooddog", {}, "yes", "no")
# => <input name="puppy[gooddog]" type="hidden" value="no" />
#    <input type="checkbox" id="puppy_gooddog" name="puppy[gooddog]" value="yes" />

# Let's say that @eula.accepted is "no":
check_box("accepted", { class: 'eula_check' }, "yes", "no")
# => <input name="eula[accepted]" type="hidden" value="no" />
#    <input type="checkbox" class="eula_check" id="eula_accepted" name="eula[accepted]" value="yes" />



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# File 'lib/action_view/helpers/form_helper.rb', line 2433

def check_box(method, options = {}, checked_value = "1", unchecked_value = "0")
  @template.check_box(@object_name, method, objectify_options(options), checked_value, unchecked_value)
end

#collection_check_boxes(method, collection, value_method, text_method, options = {}, html_options = {}, &block) ⇒ Object

Wraps ActionView::Helpers::FormOptionsHelper#collection_check_boxes for form builders:

<%= form_for @post do |f| %>
  <%= f.collection_check_boxes :author_ids, Author.all, :id, :name_with_initial %>
  <%= f.submit %>
<% end %>

Please refer to the documentation of the base helper for details.



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# File 'lib/action_view/helpers/form_options_helper.rb', line 905

def collection_check_boxes(method, collection, value_method, text_method, options = {}, html_options = {}, &block)
  @template.collection_check_boxes(@object_name, method, collection, value_method, text_method, objectify_options(options), @default_html_options.merge(html_options), &block)
end

#collection_radio_buttons(method, collection, value_method, text_method, options = {}, html_options = {}, &block) ⇒ Object

Wraps ActionView::Helpers::FormOptionsHelper#collection_radio_buttons for form builders:

<%= form_for @post do |f| %>
  <%= f.collection_radio_buttons :author_id, Author.all, :id, :name_with_initial %>
  <%= f.submit %>
<% end %>

Please refer to the documentation of the base helper for details.



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# File 'lib/action_view/helpers/form_options_helper.rb', line 917

def collection_radio_buttons(method, collection, value_method, text_method, options = {}, html_options = {}, &block)
  @template.collection_radio_buttons(@object_name, method, collection, value_method, text_method, objectify_options(options), @default_html_options.merge(html_options), &block)
end

#collection_select(method, collection, value_method, text_method, options = {}, html_options = {}) ⇒ Object

Wraps ActionView::Helpers::FormOptionsHelper#collection_select for form builders:

<%= form_for @post do |f| %>
  <%= f.collection_select :person_id, Author.all, :id, :name_with_initial, prompt: true %>
  <%= f.submit %>
<% end %>

Please refer to the documentation of the base helper for details.



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# File 'lib/action_view/helpers/form_options_helper.rb', line 857

def collection_select(method, collection, value_method, text_method, options = {}, html_options = {})
  @template.collection_select(@object_name, method, collection, value_method, text_method, objectify_options(options), @default_html_options.merge(html_options))
end

#date_select(method, options = {}, html_options = {}) ⇒ Object

Wraps ActionView::Helpers::DateHelper#date_select for form builders:

<%= form_for @person do |f| %>
  <%= f.date_select :birth_date %>
  <%= f.submit %>
<% end %>

Please refer to the documentation of the base helper for details.



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# File 'lib/action_view/helpers/date_helper.rb', line 1225

def date_select(method, options = {}, html_options = {})
  @template.date_select(@object_name, method, objectify_options(options), html_options)
end

#datetime_select(method, options = {}, html_options = {}) ⇒ Object

Wraps ActionView::Helpers::DateHelper#datetime_select for form builders:

<%= form_for @person do |f| %>
  <%= f.datetime_select :last_request_at %>
  <%= f.submit %>
<% end %>

Please refer to the documentation of the base helper for details.



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# File 'lib/action_view/helpers/date_helper.rb', line 1249

def datetime_select(method, options = {}, html_options = {})
  @template.datetime_select(@object_name, method, objectify_options(options), html_options)
end

#emitted_hidden_id? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/action_view/helpers/form_helper.rb', line 2630

def emitted_hidden_id? # :nodoc:
  @emitted_hidden_id ||= nil
end

#field_id(method, *suffixes, namespace: , index: @index) ⇒ Object

Generate an HTML id attribute value for the given field

Return the value generated by the FormBuilder for the given attribute name.

<%= form_for @post do |f| %>
  <%= f.label :title %>
  <%= f.text_field :title, aria: { describedby: f.field_id(:title, :error) } %>
  <%= tag.span("is blank", id: f.field_id(:title, :error) %>
<% end %>

In the example above, the <input type="text"> element built by the call to FormBuilder#text_field declares an aria-describedby attribute referencing the <span> element, sharing a common id root (post_title, in this case).



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# File 'lib/action_view/helpers/form_helper.rb', line 1752

def field_id(method, *suffixes, namespace: @options[:namespace], index: @index)
  @template.field_id(@object_name, method, *suffixes, namespace: namespace, index: index)
end

#field_name(method, *methods, multiple: false, index: @index) ⇒ Object

Generate an HTML name attribute value for the given name and field combination

Return the value generated by the FormBuilder for the given attribute name.

<%= form_for @post do |f| %>
  <%= f.text_field :title, name: f.field_name(:title, :subtitle) %>
  <%# => <input type="text" name="post[title][subtitle]">
<% end %>

<%= form_for @post do |f| %>
  <%= f.field_tag :tag, name: f.field_name(:tag, multiple: true) %>
  <%# => <input type="text" name="post[tag][]">
<% end %>



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# File 'lib/action_view/helpers/form_helper.rb', line 1772

def field_name(method, *methods, multiple: false, index: @index)
  object_name = @options.fetch(:as) { @object_name }

  @template.field_name(object_name, method, *methods, index: index, multiple: multiple)
end

#fields(scope = nil, model: nil, **options, &block) ⇒ Object

See the docs for the ActionView::FormHelper.fields helper method.



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# File 'lib/action_view/helpers/form_helper.rb', line 2289

def fields(scope = nil, model: nil, **options, &block)
  options[:allow_method_names_outside_object] = true
  options[:skip_default_ids] = !FormHelper.form_with_generates_ids

  convert_to_legacy_options(options)

  fields_for(scope || model, model, options, &block)
end

#fields_for(record_name, record_object = nil, fields_options = {}, &block) ⇒ Object

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.

Although the usage and purpose of fields_for is similar to form_for‘s, its method signature is slightly different. Like form_for, it yields a FormBuilder object associated with a particular model object to a block, and within the block allows methods to be called on the builder to generate fields associated with the model object. Fields may reflect a model object in two ways - how they are named (hence how submitted values appear within the params hash in the controller) and what default values are shown when the form the fields appear in is first displayed. In order for both of these features to be specified independently, both an object name (represented by either a symbol or string) and the object itself can be passed to the method separately -

<%= form_for @person do |person_form| %>
  First name: <%= person_form.text_field :first_name %>
  Last name : <%= person_form.text_field :last_name %>

  <%= fields_for :permission, @person.permission do |permission_fields| %>
    Admin?  : <%= permission_fields.check_box :admin %>
  <% end %>

  <%= person_form.submit %>
<% end %>

In this case, the checkbox field will be represented by an HTML input tag with the name attribute permission[admin], and the submitted value will appear in the controller as params[:permission][:admin]. If @person.permission is an existing record with an attribute admin, the initial state of the checkbox when first displayed will reflect the value of @person.permission.admin.

Often this can be simplified by passing just the name of the model object to fields_for -

<%= fields_for :permission do |permission_fields| %>
  Admin?: <%= permission_fields.check_box :admin %>
<% end %>

…in which case, if :permission also happens to be the name of an instance variable @permission, the initial state of the input field will reflect the value of that variable’s attribute @permission.admin.

Alternatively, you can pass just the model object itself (if the first argument isn’t a string or symbol fields_for will realize that the name has been omitted) -

<%= fields_for @person.permission do |permission_fields| %>
  Admin?: <%= permission_fields.check_box :admin %>
<% end %>

and fields_for will derive the required name of the field from the class of the model object, e.g. if @person.permission, is of class Permission, the field will still be named permission[admin].

Note: This also works for the methods in FormOptionsHelper and DateHelper that are designed to work with an object as base, like FormOptionsHelper#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 :address is called address_attributes=.

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 address reader method and responds to the address_attributes= 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 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 :allow_destroy 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 _destroy parameter, with a value that evaluates to true, you will destroy the associated model (e.g. 1, ‘1’, true, or ‘true’):

<%= form_for @person do |person_form| %>
  ...
  <%= person_form.fields_for :address do |address_fields| %>
    ...
    Delete: <%= address_fields.check_box :_destroy %>
  <% end %>
  ...
<% end %>

One-to-many

Consider a Person class which returns an array of Project instances from the projects reader method and responds to the projects_attributes= writer method:

class Person
  def projects
    [@project1, @project2]
  end

  def projects_attributes=(attributes)
    # Process the attributes hash
  end
end

Note that the projects_attributes= writer method is in fact required for fields_for to correctly identify :projects as a collection, and the correct indices to be set in the form markup.

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

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 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 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 %>

Or a collection to be used:

<%= form_for @person do |person_form| %>
  ...
  <%= person_form.fields_for :projects, @active_projects do |project_fields| %>
    Name: <%= project_fields.text_field :name %>
  <% end %>
  ...
<% end %>

If you want to destroy any of the associated models through the form, you have to enable it first using the :allow_destroy 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 _destroy parameter with a value that evaluates to true (e.g. 1, ‘1’, true, or ‘true’):

<%= form_for @person do |person_form| %>
  ...
  <%= person_form.fields_for :projects do |project_fields| %>
    Delete: <%= project_fields.check_box :_destroy %>
  <% end %>
  ...
<% end %>

When a collection is used you might want to know the index of each object into the array. For this purpose, the index method is available in the FormBuilder object.

<%= form_for @person do |person_form| %>
  ...
  <%= person_form.fields_for :projects do |project_fields| %>
    Project #<%= project_fields.index %>
    ...
  <% end %>
  ...
<% end %>

Note that fields_for will automatically generate a hidden field to store the ID of the record. There are circumstances where this hidden field is not needed and you can pass include_id: false to prevent fields_for from rendering it automatically.



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# File 'lib/action_view/helpers/form_helper.rb', line 2252

def fields_for(record_name, record_object = nil, fields_options = {}, &block)
  fields_options, record_object = record_object, nil if record_object.is_a?(Hash) && record_object.extractable_options?
  fields_options[:builder] ||= options[:builder]
  fields_options[:namespace] = options[:namespace]
  fields_options[:parent_builder] = self

  case record_name
  when String, Symbol
    if nested_attributes_association?(record_name)
      return fields_for_with_nested_attributes(record_name, record_object, fields_options, block)
    end
  else
    record_object = @template._object_for_form_builder(record_name)
    record_name   = model_name_from_record_or_class(record_object).param_key
  end

  object_name = @object_name
  index = if options.has_key?(:index)
    options[:index]
  elsif defined?(@auto_index)
    object_name = object_name.to_s.delete_suffix("[]")
    @auto_index
  end

  record_name = if index
    "#{object_name}[#{index}][#{record_name}]"
  elsif record_name.end_with?("[]")
    "#{object_name}[#{record_name[0..-3]}][#{record_object.id}]"
  else
    "#{object_name}[#{record_name}]"
  end
  fields_options[:child_index] = index

  @template.fields_for(record_name, record_object, fields_options, &block)
end

#file_field(method, options = {}) ⇒ Object

Returns a file upload input tag tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object). Additional options on the input tag can be passed as a hash with options. These options will be tagged onto the HTML as an HTML element attribute as in the example shown.

Using this method inside a form_with block will set the enclosing form’s encoding to multipart/form-data.

Options

  • Creates standard HTML attributes for the tag.

  • :disabled - If set to true, the user will not be able to use this input.

  • :multiple - If set to true, *in most updated browsers* the user will be allowed to select multiple files.

  • :include_hidden - When multiple: true and include_hidden: true, the field will be prefixed with an <input type="hidden"> field with an empty value to support submitting an empty collection of files.

  • :accept - If set to one or multiple mime-types, the user will be suggested a filter when choosing a file. You still need to set up model validations.

Examples

# Let's say that @user has avatar:
file_field(:avatar)
# => <input type="file" id="user_avatar" name="user[avatar]" />

# Let's say that @post has image:
file_field(:image, :multiple => true)
# => <input type="file" id="post_image" name="post[image][]" multiple="multiple" />

# Let's say that @post has attached:
file_field(:attached, accept: 'text/html')
# => <input accept="text/html" type="file" id="post_attached" name="post[attached]" />

# Let's say that @post has image:
file_field(:image, accept: 'image/png,image/gif,image/jpeg')
# => <input type="file" id="post_image" name="post[image]" accept="image/png,image/gif,image/jpeg" />

# Let's say that @attachment has file:
file_field(:file, class: 'file_input')
# => <input type="file" id="attachment_file" name="attachment[file]" class="file_input" />



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# File 'lib/action_view/helpers/form_helper.rb', line 2516

def file_field(method, options = {})
  self.multipart = true
  @template.file_field(@object_name, method, objectify_options(options))
end

#grouped_collection_select(method, collection, group_method, group_label_method, option_key_method, option_value_method, options = {}, html_options = {}) ⇒ Object

Wraps ActionView::Helpers::FormOptionsHelper#grouped_collection_select for form builders:

<%= form_for @city do |f| %>
  <%= f.grouped_collection_select :country_id, @continents, :countries, :name, :id, :name %>
  <%= f.submit %>
<% end %>

Please refer to the documentation of the base helper for details.



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# File 'lib/action_view/helpers/form_options_helper.rb', line 869

def grouped_collection_select(method, collection, group_method, group_label_method, option_key_method, option_value_method, options = {}, html_options = {})
  @template.grouped_collection_select(@object_name, method, collection, group_method, group_label_method, option_key_method, option_value_method, objectify_options(options), @default_html_options.merge(html_options))
end

#hidden_field(method, options = {}) ⇒ Object

Returns a hidden input tag tailored for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object). Additional options on the input tag can be passed as a hash with options. These options will be tagged onto the HTML as an HTML element attribute as in the example shown.

Examples

# Let's say that @signup.pass_confirm returns true:
hidden_field(:pass_confirm)
# => <input type="hidden" id="signup_pass_confirm" name="signup[pass_confirm]" value="true" />

# Let's say that @post.tag_list returns "blog, ruby":
hidden_field(:tag_list)
# => <input type="hidden" id="post_tag_list" name="post[tag_list]" value="blog, ruby" />

# Let's say that @user.token returns "abcde":
hidden_field(:token)
# => <input type="hidden" id="user_token" name="user[token]" value="abcde" />



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# File 'lib/action_view/helpers/form_helper.rb', line 2477

def hidden_field(method, options = {})
  @emitted_hidden_id = true if method == :id
  @template.hidden_field(@object_name, method, objectify_options(options))
end

#id ⇒ Object

Generate an HTML id attribute value.

return the <form> element’s id attribute.

<%= form_for @post do |f| %>
  <%# ... %>

  <% content_for :sticky_footer do %>
    <%= form.button(form: f.id) %>
  <% end %>
<% end %>

In the example above, the :sticky_footer content area will exist outside of the <form> element. By declaring the form HTML attribute, we hint to the browser that the generated <button> element should be treated as the <form> element’s submit button, regardless of where it exists in the DOM.



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# File 'lib/action_view/helpers/form_helper.rb', line 1732

def id
  options.dig(:html, :id)
end

#label(method, text = nil, options = {}, &block) ⇒ Object

Returns a label tag tailored for labelling an input field for a specified attribute (identified by method) on an object assigned to the template (identified by object). The text of label will default to the attribute name unless a translation is found in the current I18n locale (through helpers.label.<modelname>.<attribute>) or you specify it explicitly. Additional options on the label tag can be passed as a hash with options. These options will be tagged onto the HTML as an HTML element attribute as in the example shown, except for the :value option, which is designed to target labels for radio_button tags (where the value is used in the ID of the input tag).

Examples

label(:title)
# => <label for="post_title">Title</label>

You can localize your labels based on model and attribute names. For example you can define the following in your locale (e.g. en.yml)

helpers:
  label:
    post:
      body: "Write your entire text here"

Which then will result in

label(:body)
# => <label for="post_body">Write your entire text here</label>

Localization can also be based purely on the translation of the attribute-name (if you are using ActiveRecord):

activerecord:
  attributes:
    post:
      cost: "Total cost"

label(:cost)
# => <label for="post_cost">Total cost</label>

label(:title, "A short title")
# => <label for="post_title">A short title</label>

label(:title, "A short title", class: "title_label")
# => <label for="post_title" class="title_label">A short title</label>

label(:privacy, "Public Post", value: "public")
# => <label for="post_privacy_public">Public Post</label>

label(:cost) do |translation|
  content_tag(:span, translation, class: "cost_label")
end
# => <label for="post_cost"><span class="cost_label">Total cost</span></label>

label(:cost) do |builder|
  content_tag(:span, builder.translation, class: "cost_label")
end
# => <label for="post_cost"><span class="cost_label">Total cost</span></label>

label(:cost) do |builder|
  content_tag(:span, builder.translation, class: [
    "cost_label",
    ("error_label" if builder.object.errors.include?(:cost))
  ])
end
# => <label for="post_cost"><span class="cost_label error_label">Total cost</span></label>

label(:terms) do
  raw('Accept <a href="/terms">Terms</a>.')
end
# => <label for="post_terms">Accept <a href="/terms">Terms</a>.</label>



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# File 'lib/action_view/helpers/form_helper.rb', line 2364

def label(method, text = nil, options = {}, &block)
  @template.label(@object_name, method, text, objectify_options(options), &block)
end

#radio_button(method, tag_value, options = {}) ⇒ Object

Returns a radio button tag for accessing a specified attribute (identified by method) on an object assigned to the template (identified by object). If the current value of method is tag_value the radio button will be checked.

To force the radio button to be checked pass checked: true in the options hash. You may pass HTML options there as well.

# Let's say that @post.category returns "rails":
radio_button("category", "rails")
radio_button("category", "java")
# => <input type="radio" id="post_category_rails" name="post[category]" value="rails" checked="checked" />
#    <input type="radio" id="post_category_java" name="post[category]" value="java" />

# Let's say that @user.receive_newsletter returns "no":
radio_button("receive_newsletter", "yes")
radio_button("receive_newsletter", "no")
# => <input type="radio" id="user_receive_newsletter_yes" name="user[receive_newsletter]" value="yes" />
#    <input type="radio" id="user_receive_newsletter_no" name="user[receive_newsletter]" value="no" checked="checked" />



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# File 'lib/action_view/helpers/form_helper.rb', line 2455

def radio_button(method, tag_value, options = {})
  @template.radio_button(@object_name, method, tag_value, objectify_options(options))
end

#select(method, choices = nil, options = {}, html_options = {}, &block) ⇒ Object

Wraps ActionView::Helpers::FormOptionsHelper#select for form builders:

<%= form_for @post do |f| %>
  <%= f.select :person_id, Person.all.collect { |p| [ p.name, p.id ] }, include_blank: true %>
  <%= f.submit %>
<% end %>

Please refer to the documentation of the base helper for details.



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# File 'lib/action_view/helpers/form_options_helper.rb', line 845

def select(method, choices = nil, options = {}, html_options = {}, &block)
  @template.select(@object_name, method, choices, objectify_options(options), @default_html_options.merge(html_options), &block)
end

#selector ⇒ Object

:method: range_field

:call-seq: range_field(method, options = {})

Wraps ActionView::Helpers::FormHelper#range_field for form builders:

<%= form_with model: @user do |f| %>
  <%= f.range_field :age %>
<% end %>

Please refer to the documentation of the base helper for details.



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# File 'lib/action_view/helpers/form_helper.rb', line 1999

(field_helpers - [:label, :check_box, :radio_button, :fields_for, :fields, :hidden_field, :file_field]).each do |selector|
  class_eval <<-RUBY_EVAL, __FILE__, __LINE__ + 1
    def #{selector}(method, options = {})  # def text_field(method, options = {})
      @template.public_send(               #   @template.public_send(
        #{selector.inspect},               #     :text_field,
        @object_name,                      #     @object_name,
        method,                            #     method,
        objectify_options(options))        #     objectify_options(options))
    end                                    # end
  RUBY_EVAL
end

#submit(value = nil, options = {}) ⇒ Object

Add the submit button for the given form. When no value is given, it checks if the object is a new resource or not to create the proper label:

<%= form_for @post do |f| %>
  <%= f.submit %>
<% end %>

In the example above, if @post is a new record, it will use “Create Post” as submit button label; otherwise, it uses “Update Post”.

Those labels can be customized using I18n under the helpers.submit key and using %{model} for translation interpolation:

en:
  helpers:
    submit:
      create: "Create a %{model}"
      update: "Confirm changes to %{model}"

It also searches for a key specific to the given object:

en:
  helpers:
    submit:
      post:
        create: "Add %{model}"



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# File 'lib/action_view/helpers/form_helper.rb', line 2548

def submit(value = nil, options = {})
  value, options = nil, value if value.is_a?(Hash)
  value ||= submit_default_value
  @template.submit_tag(value, options)
end

#time_select(method, options = {}, html_options = {}) ⇒ Object

Wraps ActionView::Helpers::DateHelper#time_select for form builders:

<%= form_for @race do |f| %>
  <%= f.time_select :average_lap %>
  <%= f.submit %>
<% end %>

Please refer to the documentation of the base helper for details.



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# File 'lib/action_view/helpers/date_helper.rb', line 1237

def time_select(method, options = {}, html_options = {})
  @template.time_select(@object_name, method, objectify_options(options), html_options)
end

#time_zone_select(method, priority_zones = nil, options = {}, html_options = {}) ⇒ Object

Wraps ActionView::Helpers::FormOptionsHelper#time_zone_select for form builders:

<%= form_for @user do |f| %>
  <%= f.time_zone_select :time_zone, nil, include_blank: true %>
  <%= f.submit %>
<% end %>

Please refer to the documentation of the base helper for details.



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# File 'lib/action_view/helpers/form_options_helper.rb', line 881

def time_zone_select(method, priority_zones = nil, options = {}, html_options = {})
  @template.time_zone_select(@object_name, method, priority_zones, objectify_options(options), @default_html_options.merge(html_options))
end

#to_model ⇒ Object 



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# File 'lib/action_view/helpers/form_helper.rb', line 1691

def to_model
  self
end

#to_partial_path ⇒ Object 



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# File 'lib/action_view/helpers/form_helper.rb', line 1687

def to_partial_path
  self.class._to_partial_path
end

#weekday_select(method, options = {}, html_options = {}) ⇒ Object

Wraps ActionView::Helpers::FormOptionsHelper#weekday_select for form builders:

<%= form_for @user do |f| %>
  <%= f.weekday_select :weekday, include_blank: true %>
  <%= f.submit %>
<% end %>

Please refer to the documentation of the base helper for details.



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# File 'lib/action_view/helpers/form_options_helper.rb', line 893

def weekday_select(method, options = {}, html_options = {})
  @template.weekday_select(@object_name, method, objectify_options(options), @default_html_options.merge(html_options))
end