Module: ActionView::Helpers::FormOptionsHelper

Includes:
ERB::Util
Included in:
ActionView::Helpers, InstanceTag
Defined in:
lib/action_view/helpers/form_options_helper.rb

Overview

Provides a number of methods for turning different kinds of containers into a set of option tags.

Options

The collection_select, country_select, select, and time_zone_select methods take an options parameter, a hash.

  • :include_blank - set to true or a prompt string if the first option element of the select element is a blank. Useful if there is not a default value required for the select element.

For example,

select("post", "category", Post::CATEGORIES, {:include_blank => true})

could become:

<select name="post[category]">
  <option></option>
  <option>joke</option>
  <option>poem</option>
</select>

Another common case is a select tag for an belongs_to-associated object.

Example with @post.person_id => 2:

select("post", "person_id", Person.find(:all).collect {|p| [ p.name, p.id ] }, {:include_blank => 'None'})

could become:

<select name="post[person_id]">
  <option value="">None</option>
  <option value="1">David</option>
  <option value="2" selected="selected">Sam</option>
  <option value="3">Tobias</option>
</select>
  • :prompt - set to true or a prompt string. When the select element doesn't have a value yet, this prepends an option with a generic prompt – “Please select” – or the given prompt string.

Example:

select("post", "person_id", Person.find(:all).collect {|p| [ p.name, p.id ] }, {:prompt => 'Select Person'})

could become:

<select name="post[person_id]">
  <option value="">Select Person</option>
  <option value="1">David</option>
  <option value="2">Sam</option>
  <option value="3">Tobias</option>
</select>

Like the other form helpers, select can accept an :index option to manually set the ID used in the resulting output. Unlike other helpers, select expects this option to be in the html_options parameter.

Example:

select("album[]", "genre", %w[rap rock country], {}, { :index => nil })

becomes:

<select name="album[][genre]" id="album__genre">
  <option value="rap">rap</option>
  <option value="rock">rock</option>
  <option value="country">country</option>
</select>

Constant Summary

Constants included from ERB::Util

ERB::Util::HTML_ESCAPE, ERB::Util::JSON_ESCAPE

Instance Method Summary collapse

Methods included from ERB::Util

#html_escape, j, json_escape

Instance Method Details

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

Returns <select> and <option> tags for the collection of existing return values of method for object's class. The value returned from calling method on the instance object will be selected. If calling method returns nil, no selection is made without including :prompt or :include_blank in the options hash.

The :value_method and :text_method parameters are methods to be called on each member of collection. The return values are used as the value attribute and contents of each <option> tag, respectively.

Example object structure for use with this method:

class Post < ActiveRecord::Base
  belongs_to :author
end
class Author < ActiveRecord::Base
  has_many :posts
  def name_with_initial
    "#{first_name.first}. #{last_name}"
  end
end

Sample usage (selecting the associated Author for an instance of Post, @post):

collection_select(:post, :author_id, Author.find(:all), :id, :name_with_initial, {:prompt => true})

If @post.author_id is already 1, this would return:

<select name="post[author_id]">
  <option value="">Please select</option>
  <option value="1" selected="selected">D. Heinemeier Hansson</option>
  <option value="2">D. Thomas</option>
  <option value="3">M. Clark</option>
</select>

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# File 'lib/action_view/helpers/form_options_helper.rb', line 132

def collection_select(object, method, collection, value_method, text_method, options = {}, html_options = {})
  InstanceTag.new(object, method, self, options.delete(:object)).to_collection_select_tag(collection, value_method, text_method, options, html_options)
end

#option_groups_from_collection_for_select(collection, group_method, group_label_method, option_key_method, option_value_method, selected_key = nil) ⇒ Object

Returns a string of <option> tags, like options_from_collection_for_select, but groups them by <optgroup> tags based on the object relationships of the arguments.

Parameters:

  • collection - An array of objects representing the <optgroup> tags.

  • group_method - The name of a method which, when called on a member of collection, returns an array of child objects representing the <option> tags.

  • group_label_method+ - The name of a method which, when called on a member of collection, returns a string to be used as the label attribute for its <optgroup> tag.

  • option_key_method - The name of a method which, when called on a child object of a member of collection, returns a value to be used as the value attribute for its <option> tag.

  • option_value_method - The name of a method which, when called on a child object of a member of collection, returns a value to be used as the contents of its <option> tag.

  • selected_key - A value equal to the value attribute for one of the <option> tags, which will have the selected attribute set. Corresponds to the return value of one of the calls to option_key_method. If nil, no selection is made.

Example object structure for use with this method:

class Continent < ActiveRecord::Base
  has_many :countries
  # attribs: id, name
end
class Country < ActiveRecord::Base
  belongs_to :continent
  # attribs: id, name, continent_id
end

Sample usage:

option_groups_from_collection_for_select(@continents, :countries, :name, :id, :name, 3)

Possible output:

<optgroup label="Africa">
  <option value="1">Egypt</option>
  <option value="4">Rwanda</option>
  ...
</optgroup>
<optgroup label="Asia">
  <option value="3" selected="selected">China</option>
  <option value="12">India</option>
  <option value="5">Japan</option>
  ...
</optgroup>

Note: Only the <optgroup> and <option> tags are returned, so you still have to wrap the output in an appropriate <select> tag.


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# File 'lib/action_view/helpers/form_options_helper.rb', line 263

def option_groups_from_collection_for_select(collection, group_method, group_label_method, option_key_method, option_value_method, selected_key = nil)
  collection.inject("") do |options_for_select, group|
    group_label_string = eval("group.#{group_label_method}")
    options_for_select += "<optgroup label=\"#{html_escape(group_label_string)}\">"
    options_for_select += options_from_collection_for_select(eval("group.#{group_method}"), option_key_method, option_value_method, selected_key)
    options_for_select += '</optgroup>'
  end
end

#options_for_select(container, selected = nil) ⇒ Object

Accepts a container (hash, array, enumerable, your type) and returns a string of option tags. Given a container where the elements respond to first and last (such as a two-element array), the “lasts” serve as option values and the “firsts” as option text. Hashes are turned into this form automatically, so the keys become “firsts” and values become lasts. If selected is specified, the matching “last” or element will get the selected option-tag. selected may also be an array of values to be selected when using a multiple select.

Examples (call, result):

options_for_select([["Dollar", "$"], ["Kroner", "DKK"]])
  <option value="$">Dollar</option>\n<option value="DKK">Kroner</option>

options_for_select([ "VISA", "MasterCard" ], "MasterCard")
  <option>VISA</option>\n<option selected="selected">MasterCard</option>

options_for_select({ "Basic" => "$20", "Plus" => "$40" }, "$40")
  <option value="$20">Basic</option>\n<option value="$40" selected="selected">Plus</option>

options_for_select([ "VISA", "MasterCard", "Discover" ], ["VISA", "Discover"])
  <option selected="selected">VISA</option>\n<option>MasterCard</option>\n<option selected="selected">Discover</option>

NOTE: Only the option tags are returned, you have to wrap this call in a regular HTML select tag.


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# File 'lib/action_view/helpers/form_options_helper.rb', line 190

def options_for_select(container, selected = nil)
  container = container.to_a if Hash === container

  options_for_select = container.inject([]) do |options, element|
    text, value = option_text_and_value(element)
    selected_attribute = ' selected="selected"' if option_value_selected?(value, selected)
    options << %(<option value="#{html_escape(value.to_s)}"#{selected_attribute}>#{html_escape(text.to_s)}</option>)
  end

  options_for_select.join("\n")
end

#options_from_collection_for_select(collection, value_method, text_method, selected = nil) ⇒ Object

Returns a string of option tags that have been compiled by iterating over the collection and assigning the the result of a call to the value_method as the option value and the text_method as the option text. If selected is specified, the element returning a match on value_method will get the selected option tag.

Example (call, result). Imagine a loop iterating over each person in @project.people to generate an input tag:

options_from_collection_for_select(@project.people, "id", "name")
  <option value="#{person.id}">#{person.name}</option>

NOTE: Only the option tags are returned, you have to wrap this call in a regular HTML select tag.


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# File 'lib/action_view/helpers/form_options_helper.rb', line 211

def options_from_collection_for_select(collection, value_method, text_method, selected = nil)
  options = collection.map do |element|
    [element.send(text_method), element.send(value_method)]
  end
  options_for_select(options, selected)
end

#select(object, method, choices, options = {}, html_options = {}) ⇒ Object

Create a select tag and a series of contained option tags for the provided object and method. The option currently held by the object will be selected, provided that the object is available. See options_for_select for the required format of the choices parameter.

Example with @post.person_id => 1:

select("post", "person_id", Person.find(:all).collect {|p| [ p.name, p.id ] }, { :include_blank => true })

could become:

<select name="post[person_id]">
  <option value=""></option>
  <option value="1" selected="selected">David</option>
  <option value="2">Sam</option>
  <option value="3">Tobias</option>
</select>

This can be used to provide a default set of options in the standard way: before rendering the create form, a new model instance is assigned the default options and bound to @model_name. Usually this model is not saved to the database. Instead, a second model object is created when the create request is received. This allows the user to submit a form page more than once with the expected results of creating multiple records. In addition, this allows a single partial to be used to generate form inputs for both edit and create forms.

By default, post.person_id is the selected option. Specify :selected => value to use a different selection or :selected => nil to leave all options unselected.


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# File 'lib/action_view/helpers/form_options_helper.rb', line 98

def select(object, method, choices, options = {}, html_options = {})
  InstanceTag.new(object, method, self, options.delete(:object)).to_select_tag(choices, options, html_options)
end

#time_zone_options_for_select(selected = nil, priority_zones = nil, model = ::ActiveSupport::TimeZone) ⇒ Object

Returns a string of option tags for pretty much any time zone in the world. Supply a TimeZone name as selected to have it marked as the selected option tag. You can also supply an array of TimeZone objects as priority_zones, so that they will be listed above the rest of the (long) list. (You can use TimeZone.us_zones as a convenience for obtaining a list of the US time zones, or a Regexp to select the zones of your choice)

The selected parameter must be either nil, or a string that names a TimeZone.

By default, model is the TimeZone constant (which can be obtained in Active Record as a value object). The only requirement is that the model parameter be an object that responds to all, and returns an array of objects that represent time zones.

NOTE: Only the option tags are returned, you have to wrap this call in a regular HTML select tag.


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# File 'lib/action_view/helpers/form_options_helper.rb', line 290

def time_zone_options_for_select(selected = nil, priority_zones = nil, model = ::ActiveSupport::TimeZone)
  zone_options = ""

  zones = model.all
  convert_zones = lambda { |list| list.map { |z| [ z.to_s, z.name ] } }

  if priority_zones
   if priority_zones.is_a?(Regexp)
      priority_zones = model.all.find_all {|z| z =~ priority_zones}
   end
    zone_options += options_for_select(convert_zones[priority_zones], selected)
    zone_options += "<option value=\"\" disabled=\"disabled\">-------------</option>\n"

    zones = zones.reject { |z| priority_zones.include?( z ) }
  end

  zone_options += options_for_select(convert_zones[zones], selected)
  zone_options
end

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

Return select and option tags for the given object and method, using #time_zone_options_for_select to generate the list of option tags.

In addition to the :include_blank option documented above, this method also supports a :model option, which defaults to TimeZone. This may be used by users to specify a different time zone model object. (See time_zone_options_for_select for more information.)

You can also supply an array of TimeZone objects as priority_zones, so that they will be listed above the rest of the (long) list. (You can use TimeZone.us_zones as a convenience for obtaining a list of the US time zones, or a Regexp to select the zones of your choice)

Finally, this method supports a :default option, which selects a default TimeZone if the object's time zone is nil.

Examples:

time_zone_select( "user", "time_zone", nil, :include_blank => true)

time_zone_select( "user", "time_zone", nil, :default => "Pacific Time (US & Canada)" )

time_zone_select( "user", 'time_zone', TimeZone.us_zones, :default => "Pacific Time (US & Canada)")

time_zone_select( "user", 'time_zone', [ TimeZone['Alaska'], TimeZone['Hawaii'] ])

time_zone_select( "user", 'time_zone', /Australia/)

time_zone_select( "user", "time_zone", TZInfo::Timezone.all.sort, :model => TZInfo::Timezone)

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# File 'lib/action_view/helpers/form_options_helper.rb', line 166

def time_zone_select(object, method, priority_zones = nil, options = {}, html_options = {})
  InstanceTag.new(object, method, self,  options.delete(:object)).to_time_zone_select_tag(priority_zones, options, html_options)
end