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Module: ActionView::Helpers::TagHelper

Overview

Action View Tag Helpers

Provides methods to generate HTML tags programmatically both as a modern HTML5 compliant builder style and legacy XHTML compliant tags.

Constant Summary

Class Method Summary

Instance Method Summary

OutputSafetyHelper - Included

#raw

This method outputs without escaping a string.
#safe_join

This method returns an HTML safe string similar to what Array#join would return.
#to_sentence

Converts the array to a comma-separated sentence where the last element is joined by the connector word.

CaptureHelper - Included

#capture

The capture method extracts part of a template as a string object.
#content_for

Calling content_for stores a block of markup in an identifier for later use.
#content_for?

content_for? checks whether any content has been captured yet using content_for.
#provide

The same as content_for but when used with streaming flushes straight back to the layout.
#with_output_buffer

Use an alternate output buffer for the duration of the block.

Class Method Details

.build_tag_values(*args) (mod_func)

[ GitHub ] 

  


# File 'actionview/lib/action_view/helpers/tag_helper.rb', line 1857



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


  








  

    .ensure_valid_html5_tag_name(name)   (mod_func)
  



  

    
  





  
Raises:


    
  
  • 
    (ArgumentError)
  
    • 





  [ GitHub ]


  

  


# File 'actionview/lib/action_view/helpers/tag_helper.rb', line 1852



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


  







Instance Method Details



  

    #cdata_section(content)  
  



  

    
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
 and end with (and may not contain) the string ]]>.


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]]>

  



  [ GitHub ]


  

  


# File 'actionview/lib/action_view/helpers/tag_helper.rb', line 1833



def cdata_section(content)
  splitted = content.to_s.gsub(/\]\]>/, "]]]]><![CDATA[>")
  "<![CDATA[#{splitted}]]>".html_safe
end


  








  

    #class_names(*args)  
  



  

    
Alias for #token_list.

  



  [ GitHub ]


  

  


# File 'actionview/lib/action_view/helpers/tag_helper.rb', line 1816



alias_method :class_names, :token_list


  








  

    #content_tag(name, content_or_options_with_block = nil, options = nil, escape = true, &block)  
  



  

    
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 (disabled and
readonly), 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>

  



  [ GitHub ]


  

  


# File 'actionview/lib/action_view/helpers/tag_helper.rb', line 1777



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


  








  

    #escape_once(html)  
  



  

    
Returns an escaped version of html without affecting existing escaped entities.


escape_once("1 < 2 &amp; 3")
#### => "1 &lt; 2 &amp; 3"

escape_once("&lt;&lt; Accept & Checkout")
#### => "&lt;&lt; Accept &amp; Checkout"

  



  [ GitHub ]


  

  


# File 'actionview/lib/action_view/helpers/tag_helper.rb', line 1847



def escape_once(html)
  ERB::Util.html_escape_once(html)
end


  








  

    #tag(name = nil, options = nil, open = false, escape = true)  
  



  

    
Modern syntax


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.


Returns an instance of TagBuilder when invoked without positional,
keyword, or block arguments.


Legacy syntax


Returns an HTML tag.


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 data-* 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 &amp; shut.png" />

tag("img", { src: "open &amp; shut.png" }, false, false)
#### => <img src="open &amp; shut.png" />

tag("div", data: { name: 'Stephen', city_state: %w(Chicago IL) })
#### => <div data-name="Stephen" data-city-state="[&quot;Chicago&quot;,&quot;IL&quot;]" />

tag("div", class: { highlight: current_user.admin? })
#### => <div class="highlight" />

  



  [ GitHub ]


  

  


# File 'actionview/lib/action_view/helpers/tag_helper.rb', line 1736



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


  








  

    #tag_builder   (private)
  

  [ GitHub ]


  

  


# File 'actionview/lib/action_view/helpers/tag_helper.rb', line 1877



def tag_builder
  @tag_builder ||= TagBuilder.new(self)
end


  








  

    #token_list(*args)  
    Also known as: #class_names
  



  

    
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"

  



  [ GitHub ]


  

  


# File 'actionview/lib/action_view/helpers/tag_helper.rb', line 1802



def token_list(*args)
  tokens = []
  build_tag_values(*args).each do |value|
    value = value.to_s
    value = CGI.unescape_html(value) if value.include?("&")
    # The block form of split yields each token without building an
    # array per value.
    value.split(/\s+/) { |token| tokens << token }
  end
  tokens.uniq!

  # Inlined safe_join: the tokens are already a flat array.
  tokens.map! { |token| ERB::Util.unwrapped_html_escape(token) }.join(" ").html_safe
end