actionview/lib/action_view/helpers/tag_helper.rb
# frozen_string_literal: true
require "active_support/code_generator"
require "active_support/core_ext/enumerable"
require "active_support/core_ext/string/output_safety"
require "active_support/core_ext/string/inflections"
require "set"
require "action_view/helpers/capture_helper"
require "action_view/helpers/output_safety_helper"
module ActionView
module Helpers # :nodoc:
# = Action View Tag \Helpers
#
# Provides methods to generate HTML tags programmatically both as a modern
# HTML5 compliant builder style and legacy XHTML compliant tags.
module TagHelper
include CaptureHelper
include OutputSafetyHelper
BOOLEAN_ATTRIBUTES = %w(allowfullscreen allowpaymentrequest async autofocus
autoplay checked compact controls declare default
defaultchecked defaultmuted defaultselected defer
disabled enabled formnovalidate hidden indeterminate
inert ismap itemscope loop multiple muted nohref
nomodule noresize noshade novalidate nowrap open
pauseonexit playsinline readonly required reversed
scoped seamless selected sortable truespeed
typemustmatch visible).to_set
BOOLEAN_ATTRIBUTES.merge(BOOLEAN_ATTRIBUTES.map(&:to_sym))
BOOLEAN_ATTRIBUTES.freeze
ARIA_PREFIXES = ["aria", :aria].to_set.freeze
DATA_PREFIXES = ["data", :data].to_set.freeze
TAG_TYPES = {}
TAG_TYPES.merge! BOOLEAN_ATTRIBUTES.index_with(:boolean)
TAG_TYPES.merge! DATA_PREFIXES.index_with(:data)
TAG_TYPES.merge! ARIA_PREFIXES.index_with(:aria)
TAG_TYPES.freeze
PRE_CONTENT_STRINGS = Hash.new { "" }
PRE_CONTENT_STRINGS[:textarea] = "\n"
PRE_CONTENT_STRINGS["textarea"] = "\n"
class TagBuilder # :nodoc:
include CaptureHelper
include OutputSafetyHelper
def self.define_element(name, code_generator:, method_name: name.to_s.underscore)
code_generator.define_cached_method(method_name, namespace: :tag_builder) do |batch|
batch.push(<<~RUBY) unless instance_methods.include?(method_name.to_sym)
def #{method_name}(content = nil, escape: true, **options, &block)
tag_string("#{name}", content, options, escape: escape, &block)
end
RUBY
end
end
def self.define_void_element(name, code_generator:, method_name: name.to_s.underscore)
code_generator.define_cached_method(method_name, namespace: :tag_builder) do |batch|
batch.push(<<~RUBY)
def #{method_name}(content = nil, escape: true, **options, &block)
if content || block
ActionView.deprecator.warn <<~TEXT
Putting content inside a void element (#{name}) is invalid
according to the HTML5 spec, and so it is being deprecated
without replacement. In Rails 7.3, passing content as a
positional argument will raise, and using a block will have
no effect.
TEXT
tag_string("#{name}", content, options, escape: escape, &block)
else
self_closing_tag_string("#{name}", options, escape, ">")
end
end
RUBY
end
end
def self.define_self_closing_element(name, code_generator:, method_name: name.to_s.underscore)
code_generator.define_cached_method(method_name, namespace: :tag_builder) do |batch|
batch.push(<<~RUBY)
def #{method_name}(content = nil, escape: true, **options, &block)
if content || block
tag_string("#{name}", content, options, escape: escape, &block)
else
self_closing_tag_string("#{name}", options, escape)
end
end
RUBY
end
end
ActiveSupport::CodeGenerator.batch(self, __FILE__, __LINE__) do |code_generator|
define_void_element :area, code_generator: code_generator
define_void_element :base, code_generator: code_generator
define_void_element :br, code_generator: code_generator
define_void_element :col, code_generator: code_generator
define_void_element :embed, code_generator: code_generator
define_void_element :hr, code_generator: code_generator
define_void_element :img, code_generator: code_generator
define_void_element :input, code_generator: code_generator
define_void_element :keygen, code_generator: code_generator
define_void_element :link, code_generator: code_generator
define_void_element :meta, code_generator: code_generator
define_void_element :source, code_generator: code_generator
define_void_element :track, code_generator: code_generator
define_void_element :wbr, code_generator: code_generator
define_self_closing_element :animate, code_generator: code_generator
define_self_closing_element :animateMotion, code_generator: code_generator
define_self_closing_element :animateTransform, code_generator: code_generator
define_self_closing_element :circle, code_generator: code_generator
define_self_closing_element :ellipse, code_generator: code_generator
define_self_closing_element :line, code_generator: code_generator
define_self_closing_element :path, code_generator: code_generator
define_self_closing_element :polygon, code_generator: code_generator
define_self_closing_element :polyline, code_generator: code_generator
define_self_closing_element :rect, code_generator: code_generator
define_self_closing_element :set, code_generator: code_generator
define_self_closing_element :stop, code_generator: code_generator
define_self_closing_element :use, code_generator: code_generator
define_self_closing_element :view, code_generator: code_generator
define_element :a, code_generator: code_generator
define_element :abbr, code_generator: code_generator
define_element :address, code_generator: code_generator
define_element :article, code_generator: code_generator
define_element :aside, code_generator: code_generator
define_element :audio, code_generator: code_generator
define_element :b, code_generator: code_generator
define_element :bdi, code_generator: code_generator
define_element :bdo, code_generator: code_generator
define_element :blockquote, code_generator: code_generator
define_element :body, code_generator: code_generator
define_element :button, code_generator: code_generator
define_element :canvas, code_generator: code_generator
define_element :caption, code_generator: code_generator
define_element :cite, code_generator: code_generator
define_element :code, code_generator: code_generator
define_element :colgroup, code_generator: code_generator
define_element :data, code_generator: code_generator
define_element :datalist, code_generator: code_generator
define_element :dd, code_generator: code_generator
define_element :del, code_generator: code_generator
define_element :details, code_generator: code_generator
define_element :dfn, code_generator: code_generator
define_element :dialog, code_generator: code_generator
define_element :div, code_generator: code_generator
define_element :dl, code_generator: code_generator
define_element :dt, code_generator: code_generator
define_element :em, code_generator: code_generator
define_element :fieldset, code_generator: code_generator
define_element :figcaption, code_generator: code_generator
define_element :figure, code_generator: code_generator
define_element :footer, code_generator: code_generator
define_element :form, code_generator: code_generator
define_element :h1, code_generator: code_generator
define_element :h2, code_generator: code_generator
define_element :h3, code_generator: code_generator
define_element :h4, code_generator: code_generator
define_element :h5, code_generator: code_generator
define_element :h6, code_generator: code_generator
define_element :head, code_generator: code_generator
define_element :header, code_generator: code_generator
define_element :hgroup, code_generator: code_generator
define_element :html, code_generator: code_generator
define_element :i, code_generator: code_generator
define_element :iframe, code_generator: code_generator
define_element :ins, code_generator: code_generator
define_element :kbd, code_generator: code_generator
define_element :label, code_generator: code_generator
define_element :legend, code_generator: code_generator
define_element :li, code_generator: code_generator
define_element :main, code_generator: code_generator
define_element :map, code_generator: code_generator
define_element :mark, code_generator: code_generator
define_element :menu, code_generator: code_generator
define_element :meter, code_generator: code_generator
define_element :nav, code_generator: code_generator
define_element :noscript, code_generator: code_generator
define_element :object, code_generator: code_generator
define_element :ol, code_generator: code_generator
define_element :optgroup, code_generator: code_generator
define_element :option, code_generator: code_generator
define_element :output, code_generator: code_generator
define_element :p, code_generator: code_generator
define_element :picture, code_generator: code_generator
define_element :portal, code_generator: code_generator
define_element :pre, code_generator: code_generator
define_element :progress, code_generator: code_generator
define_element :q, code_generator: code_generator
define_element :rp, code_generator: code_generator
define_element :rt, code_generator: code_generator
define_element :ruby, code_generator: code_generator
define_element :s, code_generator: code_generator
define_element :samp, code_generator: code_generator
define_element :script, code_generator: code_generator
define_element :search, code_generator: code_generator
define_element :section, code_generator: code_generator
define_element :select, code_generator: code_generator
define_element :slot, code_generator: code_generator
define_element :small, code_generator: code_generator
define_element :span, code_generator: code_generator
define_element :strong, code_generator: code_generator
define_element :style, code_generator: code_generator
define_element :sub, code_generator: code_generator
define_element :summary, code_generator: code_generator
define_element :sup, code_generator: code_generator
define_element :table, code_generator: code_generator
define_element :tbody, code_generator: code_generator
define_element :td, code_generator: code_generator
define_element :template, code_generator: code_generator
define_element :textarea, code_generator: code_generator
define_element :tfoot, code_generator: code_generator
define_element :th, code_generator: code_generator
define_element :thead, code_generator: code_generator
define_element :time, code_generator: code_generator
define_element :title, code_generator: code_generator
define_element :tr, code_generator: code_generator
define_element :u, code_generator: code_generator
define_element :ul, code_generator: code_generator
define_element :var, code_generator: code_generator
define_element :video, code_generator: code_generator
end
def initialize(view_context)
@view_context = view_context
end
# Transforms a Hash into HTML Attributes, ready to be interpolated into
# ERB.
#
# <input <%= tag.attributes(type: :text, aria: { label: "Search" }) %> >
# # => <input type="text" aria-label="Search">
def attributes(attributes)
tag_options(attributes.to_h).to_s.strip.html_safe
end
def tag_string(name, content = nil, options, escape: true, &block)
content = @view_context.capture(self, &block) if block
content_tag_string(name, content, options, escape)
end
def self_closing_tag_string(name, options, escape = true, tag_suffix = " />")
"<#{name}#{tag_options(options, escape)}#{tag_suffix}".html_safe
end
def content_tag_string(name, content, options, escape = true)
tag_options = tag_options(options, escape) if options
if escape && content.present?
content = ERB::Util.unwrapped_html_escape(content)
end
"<#{name}#{tag_options}>#{PRE_CONTENT_STRINGS[name]}#{content}</#{name}>".html_safe
end
def tag_options(options, escape = true)
return if options.blank?
output = +""
sep = " "
options.each_pair do |key, value|
type = TAG_TYPES[key]
if type == :data && value.is_a?(Hash)
value.each_pair do |k, v|
next if v.nil?
output << sep
output << prefix_tag_option(key, k, v, escape)
end
elsif type == :aria && value.is_a?(Hash)
value.each_pair do |k, v|
next if v.nil?
case v
when Array, Hash
tokens = TagHelper.build_tag_values(v)
next if tokens.none?
v = safe_join(tokens, " ")
else
v = v.to_s
end
output << sep
output << prefix_tag_option(key, k, v, escape)
end
elsif type == :boolean
if value
output << sep
output << boolean_tag_option(key)
end
elsif !value.nil?
output << sep
output << tag_option(key, value, escape)
end
end
output unless output.empty?
end
def boolean_tag_option(key)
%(#{key}="#{key}")
end
def tag_option(key, value, escape)
key = ERB::Util.xml_name_escape(key) if escape
case value
when Array, Hash
value = TagHelper.build_tag_values(value) if key.to_s == "class"
value = escape ? safe_join(value, " ") : value.join(" ")
when Regexp
value = escape ? ERB::Util.unwrapped_html_escape(value.source) : value.source
else
value = escape ? ERB::Util.unwrapped_html_escape(value) : value.to_s
end
value = value.gsub('"', """) if value.include?('"')
%(#{key}="#{value}")
end
private
def prefix_tag_option(prefix, key, value, escape)
key = "#{prefix}-#{key.to_s.dasherize}"
unless value.is_a?(String) || value.is_a?(Symbol) || value.is_a?(BigDecimal)
value = value.to_json
end
tag_option(key, value, escape)
end
def respond_to_missing?(*args)
true
end
def method_missing(called, *args, escape: true, **options, &block)
name = called.name.dasherize
TagHelper.ensure_valid_html5_tag_name(name)
tag_string(name, *args, options, escape: escape, &block)
end
end
# Returns an HTML tag.
#
# === Building HTML tags
#
# Builds HTML5 compliant tags with a tag proxy. Every tag can be built with:
#
# tag.<tag name>(optional content, options)
#
# where tag name can be e.g. br, div, section, article, or any tag really.
#
# ==== Passing content
#
# Tags can pass content to embed within it:
#
# tag.h1 'All titles fit to print' # => <h1>All titles fit to print</h1>
#
# tag.div tag.p('Hello world!') # => <div><p>Hello world!</p></div>
#
# Content can also be captured with a block, which is useful in templates:
#
# <%= tag.p do %>
# The next great American novel starts here.
# <% end %>
# # => <p>The next great American novel starts here.</p>
#
# ==== Options
#
# Use symbol keyed options to add attributes to the generated tag.
#
# tag.section class: %w( kitties puppies )
# # => <section class="kitties puppies"></section>
#
# tag.section id: dom_id(@post)
# # => <section id="<generated dom id>"></section>
#
# Pass +true+ for any attributes that can render with no values, like +disabled+ and +readonly+.
#
# tag.input type: 'text', disabled: true
# # => <input type="text" disabled="disabled">
#
# HTML5 <tt>data-*</tt> and <tt>aria-*</tt> attributes can be set with a
# single +data+ or +aria+ key pointing to a hash of sub-attributes.
#
# To play nicely with JavaScript conventions, sub-attributes are dasherized.
#
# tag.article data: { user_id: 123 }
# # => <article data-user-id="123"></article>
#
# Thus <tt>data-user-id</tt> can be accessed as <tt>dataset.userId</tt>.
#
# Data attribute values are encoded to JSON, with the exception of strings, symbols, and
# BigDecimals.
# This may come in handy when using jQuery's HTML5-aware <tt>.data()</tt>
# from 1.4.3.
#
# tag.div data: { city_state: %w( Chicago IL ) }
# # => <div data-city-state="["Chicago","IL"]"></div>
#
# The generated tag names and attributes are escaped by default. This can be disabled using
# +escape+.
#
# tag.img src: 'open & shut.png'
# # => <img src="open & shut.png">
#
# tag.img src: 'open & shut.png', escape: false
# # => <img src="open & shut.png">
#
# The tag builder respects
# {HTML5 void elements}[https://www.w3.org/TR/html5/syntax.html#void-elements]
# if no content is passed, and omits closing tags for those elements.
#
# # A standard element:
# tag.div # => <div></div>
#
# # A void element:
# tag.br # => <br>
#
# Note that when using the block form options should be wrapped in
# parenthesis.
#
# <%= tag.a(href: "/about", class: "font-bold") do %>
# About the author
# <% end %>
# # => <a href="/about" class="font-bold">About the author</a>
#
# === Building HTML attributes
#
# Transforms a Hash into HTML attributes, ready to be interpolated into
# ERB. Includes or omits boolean attributes based on their truthiness.
# Transforms keys nested within
# <tt>aria:</tt> or <tt>data:</tt> objects into <tt>aria-</tt> and <tt>data-</tt>
# prefixed attributes:
#
# <input <%= tag.attributes(type: :text, aria: { label: "Search" }) %>>
# # => <input type="text" aria-label="Search">
#
# <button <%= tag.attributes id: "call-to-action", disabled: false, aria: { expanded: false } %> class="primary">Get Started!</button>
# # => <button id="call-to-action" aria-expanded="false" class="primary">Get Started!</button>
#
# === Legacy syntax
#
# The following format is for legacy syntax support. It will be deprecated in future versions of \Rails.
#
# tag(name, options = nil, open = false, escape = true)
#
# It returns an empty HTML tag of type +name+ which by default is XHTML
# compliant. Set +open+ to true to create an open tag compatible
# with HTML 4.0 and below. Add HTML attributes by passing an attributes
# hash to +options+. Set +escape+ to false to disable attribute value
# escaping.
#
# ==== Options
#
# You can use symbols or strings for the attribute names.
#
# Use +true+ with boolean attributes that can render with no value, like
# +disabled+ and +readonly+.
#
# HTML5 <tt>data-*</tt> attributes can be set with a single +data+ key
# pointing to a hash of sub-attributes.
#
# ==== Examples
#
# tag("br")
# # => <br />
#
# tag("br", nil, true)
# # => <br>
#
# tag("input", type: 'text', disabled: true)
# # => <input type="text" disabled="disabled" />
#
# tag("input", type: 'text', class: ["strong", "highlight"])
# # => <input class="strong highlight" type="text" />
#
# tag("img", src: "open & shut.png")
# # => <img src="open & shut.png" />
#
# tag("img", { src: "open & shut.png" }, false, false)
# # => <img src="open & shut.png" />
#
# tag("div", data: { name: 'Stephen', city_state: %w(Chicago IL) })
# # => <div data-name="Stephen" data-city-state="["Chicago","IL"]" />
#
# tag("div", class: { highlight: current_user.admin? })
# # => <div class="highlight" />
def tag(name = nil, options = nil, open = false, escape = true)
if name.nil?
tag_builder
else
ensure_valid_html5_tag_name(name)
"<#{name}#{tag_builder.tag_options(options, escape) if options}#{open ? ">" : " />"}".html_safe
end
end
# Returns an HTML block tag of type +name+ surrounding the +content+. Add
# HTML attributes by passing an attributes hash to +options+.
# Instead of passing the content as an argument, you can also use a block
# in which case, you pass your +options+ as the second parameter.
# Set escape to false to disable escaping.
# Note: this is legacy syntax, see +tag+ method description for details.
#
# ==== Options
# The +options+ hash can be used with attributes with no value like (<tt>disabled</tt> and
# <tt>readonly</tt>), which you can give a value of true in the +options+ hash. You can use
# symbols or strings for the attribute names.
#
# ==== Examples
# content_tag(:p, "Hello world!")
# # => <p>Hello world!</p>
# content_tag(:div, content_tag(:p, "Hello world!"), class: "strong")
# # => <div class="strong"><p>Hello world!</p></div>
# content_tag(:div, "Hello world!", class: ["strong", "highlight"])
# # => <div class="strong highlight">Hello world!</div>
# content_tag(:div, "Hello world!", class: ["strong", { highlight: current_user.admin? }])
# # => <div class="strong highlight">Hello world!</div>
# content_tag("select", options, multiple: true)
# # => <select multiple="multiple">...options...</select>
#
# <%= content_tag :div, class: "strong" do -%>
# Hello world!
# <% end -%>
# # => <div class="strong">Hello world!</div>
def content_tag(name, content_or_options_with_block = nil, options = nil, escape = true, &block)
ensure_valid_html5_tag_name(name)
if block_given?
options = content_or_options_with_block if content_or_options_with_block.is_a?(Hash)
tag_builder.content_tag_string(name, capture(&block), options, escape)
else
tag_builder.content_tag_string(name, content_or_options_with_block, options, escape)
end
end
# Returns a string of tokens built from +args+.
#
# ==== Examples
# token_list("foo", "bar")
# # => "foo bar"
# token_list("foo", "foo bar")
# # => "foo bar"
# token_list({ foo: true, bar: false })
# # => "foo"
# token_list(nil, false, 123, "", "foo", { bar: true })
# # => "123 foo bar"
def token_list(*args)
tokens = build_tag_values(*args).flat_map { |value| CGI.unescape_html(value.to_s).split(/\s+/) }.uniq
safe_join(tokens, " ")
end
alias_method :class_names, :token_list
# Returns a CDATA section with the given +content+. CDATA sections
# are used to escape blocks of text containing characters which would
# otherwise be recognized as markup. CDATA sections begin with the string
# <tt><![CDATA[</tt> and end with (and may not contain) the string <tt>]]></tt>.
#
# cdata_section("<hello world>")
# # => <![CDATA[<hello world>]]>
#
# cdata_section(File.read("hello_world.txt"))
# # => <![CDATA[<hello from a text file]]>
#
# cdata_section("hello]]>world")
# # => <![CDATA[hello]]]]><![CDATA[>world]]>
def cdata_section(content)
splitted = content.to_s.gsub(/\]\]>/, "]]]]><![CDATA[>")
"<![CDATA[#{splitted}]]>".html_safe
end
# Returns an escaped version of +html+ without affecting existing escaped entities.
#
# escape_once("1 < 2 & 3")
# # => "1 < 2 & 3"
#
# escape_once("<< Accept & Checkout")
# # => "<< Accept & Checkout"
def escape_once(html)
ERB::Util.html_escape_once(html)
end
private
def ensure_valid_html5_tag_name(name)
raise ArgumentError, "Invalid HTML5 tag name: #{name.inspect}" unless /\A[a-zA-Z][^\s\/>]*\z/.match?(name)
end
module_function :ensure_valid_html5_tag_name
def build_tag_values(*args)
tag_values = []
args.each do |tag_value|
case tag_value
when Hash
tag_value.each do |key, val|
tag_values << key.to_s if val && key.present?
end
when Array
tag_values.concat build_tag_values(*tag_value)
else
tag_values << tag_value.to_s if tag_value.present?
end
end
tag_values
end
module_function :build_tag_values
def tag_builder
@tag_builder ||= TagBuilder.new(self)
end
end
end
end