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repeating documentation for form helpers

This commit is contained in:
Thiago Pinto 2012-12-09 15:24:44 -05:00
parent d1e70cb7b4
commit 981900259e
1 changed files with 406 additions and 18 deletions
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actionpack/lib/action_view/helpers/form_helper.rb
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@ -1226,10 +1226,255 @@ module ActionView
RUBY_EVAL
end
# Instructions for this +method+ can be found in this documentation.
# For reusability and delegation reasons, various +methods+ have equal names.
# Please, look up the next +method+ with this name
# 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 +field_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 %>
#
# <%= f.submit %>
# <% end %>
#
# In this case, the checkbox field will be represented by an HTML +input+
# tag with the +name+ attribute <tt>permission[admin]</tt>, and the submitted
# value will appear in the controller as <tt>params[:permission][:admin]</tt>.
# If <tt>@person.permission</tt> is an existing record with an attribute
# +admin+, the initial state of the checkbox when first displayed will
# reflect the value of <tt>@person.permission.admin</tt>.
#
# 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 <tt>:permission</tt> also happens to be the name of an
# instance variable <tt>@permission</tt>, the initial state of the input
# field will reflect the value of that variable's attribute <tt>@permission.admin</tt>.
#
# 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 <tt>@person.permission</tt>, is
# of class +Permission+, the field will still be named <tt>permission[admin]</tt>.
#
# 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 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>_destroy</tt> parameter,
# with a value that evaluates to +true+, you will destroy the associated
# model (eg. 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 <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
#
# Note that the <tt>projects_attributes=</tt> writer method is in fact
# required for fields_for to correctly identify <tt>:projects</tt> 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 %>
#
# 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>_destroy</tt>
# parameter with a value that evaluates to +true+
# (eg. 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 <tt>index</tt> 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 <tt>hidden_field_id: false</tt>
# to prevent fields_for from rendering it automatically.
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]
@ -1259,43 +1504,186 @@ module ActionView
@template.fields_for(record_name, record_object, fields_options, &block)
end
# Instructions for this +method+ can be found in this documentation.
# For reusability and delegation reasons, various +methods+ have equal names.
# Please, look up the next +method+ with this name
# 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 <tt>:value</tt> 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(:post, :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(:post, :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(:post, :cost)
# # => <label for="post_cost">Total cost</label>
#
# label(:post, :title, "A short title")
# # => <label for="post_title">A short title</label>
#
# label(:post, :title, "A short title", class: "title_label")
# # => <label for="post_title" class="title_label">A short title</label>
#
# label(:post, :privacy, "Public Post", value: "public")
# # => <label for="post_privacy_public">Public Post</label>
#
# label(:post, :terms) do
# 'Accept <a href="/terms">Terms</a>.'.html_safe
# end
def label(method, text = nil, options = {}, &block)
@template.label(@object_name, method, text, objectify_options(options), &block)
end
# Instructions for this +method+ can be found in this documentation.
# For reusability and delegation reasons, various +methods+ have equal names.
# Please, look up the next +method+ with this name
# 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.
#
# ==== 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_attributes(params[:invoice])
#
# wouldn't update the flag.
#
# To prevent this the helper generates an auxiliary hidden field before
# the very 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.
#
# # Let's say that @post.validated? is 1:
# check_box("post", "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("puppy", "gooddog", {}, "yes", "no")
# # => <input name="puppy[gooddog]" type="hidden" value="no" />
# # <input type="checkbox" id="puppy_gooddog" name="puppy[gooddog]" value="yes" />
#
# check_box("eula", "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" />
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
# Instructions for this +method+ can be found in this documentation.
# For reusability and delegation reasons, various +methods+ have equal names.
# Please, look up the next +method+ with this name
# 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 <tt>checked: true</tt> in the
# +options+ hash. You may pass HTML options there as well.
#
# # Let's say that @post.category returns "rails":
# radio_button("post", "category", "rails")
# radio_button("post", "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" />
#
# radio_button("user", "receive_newsletter", "yes")
# radio_button("user", "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" />
def radio_button(method, tag_value, options = {})
@template.radio_button(@object_name, method, tag_value, objectify_options(options))
end
# Instructions for this +method+ can be found in this documentation.
# For reusability and delegation reasons, various +methods+ have equal names.
# Please, look up the next +method+ with this name
# 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
# hidden_field(:signup, :pass_confirm)
# # => <input type="hidden" id="signup_pass_confirm" name="signup[pass_confirm]" value="#{@signup.pass_confirm}" />
#
# hidden_field(:post, :tag_list)
# # => <input type="hidden" id="post_tag_list" name="post[tag_list]" value="#{@post.tag_list}" />
#
# hidden_field(:user, :token)
# # => <input type="hidden" id="user_token" name="user[token]" value="#{@user.token}" />
#
def hidden_field(method, options = {})
@emitted_hidden_id = true if method == :id
@template.hidden_field(@object_name, method, objectify_options(options))
end
# Instructions for this +method+ can be found in this documentation.
# For reusability and delegation reasons, various +methods+ have equal names.
# Please, look up the next +method+ with this name
# 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_for+ block will set the enclosing form's encoding to <tt>multipart/form-data</tt>.
#
# ==== Options
# * Creates standard HTML attributes for the tag.
# * <tt>:disabled</tt> - If set to true, the user will not be able to use this input.
# * <tt>:multiple</tt> - If set to true, *in most updated browsers* the user will be allowed to select multiple files.
# * <tt>:accept</tt> - 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
# file_field(:user, :avatar)
# # => <input type="file" id="user_avatar" name="user[avatar]" />
#
# file_field(:post, :image, :multiple => true)
# # => <input type="file" id="post_image" name="post[image]" multiple="true" />
#
# file_field(:post, :attached, accept: 'text/html')
# # => <input accept="text/html" type="file" id="post_attached" name="post[attached]" />
#
# file_field(:post, :image, accept: 'image/png,image/gif,image/jpeg')
# # => <input type="file" id="post_image" name="post[image]" accept="image/png,image/gif,image/jpeg" />
#
# file_field(:attachment, :file, class: 'file_input')
# # => <input type="file" id="attachment_file" name="attachment[file]" class="file_input" />
def file_field(method, options = {})
self.multipart = true
@template.file_field(@object_name, method, objectify_options(options))