vendor/rails/actionpack/lib/action_view/helpers/tag_helper.rb

   1 require 'action_view/erb/util'
   2 require 'set'
   3
   4 module ActionView
   5   module Helpers #:nodoc:
   6     # Provides methods to generate HTML tags programmatically when you can't use
   7     # a Builder. By default, they output XHTML compliant tags.
   8     module TagHelper
   9       include ERB::Util
  10
  11       BOOLEAN_ATTRIBUTES = %w(disabled readonly multiple checked).to_set
  12       BOOLEAN_ATTRIBUTES.merge(BOOLEAN_ATTRIBUTES.map(&:to_sym))
  13
  14       # Returns an empty HTML tag of type +name+ which by default is XHTML
  15       # compliant. Set +open+ to true to create an open tag compatible
  16       # with HTML 4.0 and below. Add HTML attributes by passing an attributes
  17       # hash to +options+. Set +escape+ to false to disable attribute value
  18       # escaping.
  19       #
  20       # ==== Options
  21       # The +options+ hash is used with attributes with no value like (<tt>disabled</tt> and
  22       # <tt>readonly</tt>), which you can give a value of true in the +options+ hash. You can use
  23       # symbols or strings for the attribute names.
  24       #
  25       # ==== Examples
  26       #   tag("br")
  27       #   # => <br />
  28       #
  29       #   tag("br", nil, true)
  30       #   # => <br>
  31       #
  32       #   tag("input", { :type => 'text', :disabled => true })
  33       #   # => <input type="text" disabled="disabled" />
  34       #
  35       #   tag("img", { :src => "open & shut.png" })
  36       #   # => <img src="open &amp; shut.png" />
  37       #
  38       #   tag("img", { :src => "open &amp; shut.png" }, false, false)
  39       #   # => <img src="open &amp; shut.png" />
  40       def tag(name, options = nil, open = false, escape = true)
  41         "<#{name}#{tag_options(options, escape) if options}#{open ? ">" : " />"}"
  42       end
  43
  44       # Returns an HTML block tag of type +name+ surrounding the +content+. Add
  45       # HTML attributes by passing an attributes hash to +options+.
  46       # Instead of passing the content as an argument, you can also use a block
  47       # in which case, you pass your +options+ as the second parameter.
  48       # Set escape to false to disable attribute value escaping.
  49       #
  50       # ==== Options
  51       # The +options+ hash is used with attributes with no value like (<tt>disabled</tt> and
  52       # <tt>readonly</tt>), which you can give a value of true in the +options+ hash. You can use
  53       # symbols or strings for the attribute names.
  54       #
  55       # ==== Examples
  56       #   content_tag(:p, "Hello world!")
  57       #    # => <p>Hello world!</p>
  58       #   content_tag(:div, content_tag(:p, "Hello world!"), :class => "strong")
  59       #    # => <div class="strong"><p>Hello world!</p></div>
  60       #   content_tag("select", options, :multiple => true)
  61       #    # => <select multiple="multiple">...options...</select>
  62       #
  63       #   <% content_tag :div, :class => "strong" do -%>
  64       #     Hello world!
  65       #   <% end -%>
  66       #    # => <div class="strong">Hello world!</div>
  67       def content_tag(name, content_or_options_with_block = nil, options = nil, escape = true, &block)
  68         if block_given?
  69           options = content_or_options_with_block if content_or_options_with_block.is_a?(Hash)
  70           content_tag = content_tag_string(name, capture(&block), options, escape)
  71
  72           if block_called_from_erb?(block)
  73             concat(content_tag)
  74           else
  75             content_tag
  76           end
  77         else
  78           content_tag_string(name, content_or_options_with_block, options, escape)
  79         end
  80       end
  81
  82       # Returns a CDATA section with the given +content+.  CDATA sections
  83       # are used to escape blocks of text containing characters which would
  84       # otherwise be recognized as markup. CDATA sections begin with the string
  85       # <tt><![CDATA[</tt> and end with (and may not contain) the string <tt>]]></tt>.
  86       #
  87       # ==== Examples
  88       #   cdata_section("<hello world>")
  89       #   # => <![CDATA[<hello world>]]>
  90       #
  91       #   cdata_section(File.read("hello_world.txt"))
  92       #   # => <![CDATA[<hello from a text file]]>
  93       def cdata_section(content)
  94         "<![CDATA[#{content}]]>"
  95       end
  96
  97       # Returns an escaped version of +html+ without affecting existing escaped entities.
  98       #
  99       # ==== Examples
 100       #   escape_once("1 < 2 &amp; 3")
 101       #   # => "1 &lt; 2 &amp; 3"
 102       #
 103       #   escape_once("&lt;&lt; Accept & Checkout")
 104       #   # => "&lt;&lt; Accept &amp; Checkout"
 105       def escape_once(html)
 106         html.to_s.gsub(/[\"><]|&(?!([a-zA-Z]+|(#\d+));)/) { |special| ERB::Util::HTML_ESCAPE[special] }
 107       end
 108
 109       private
 110         BLOCK_CALLED_FROM_ERB = 'defined? __in_erb_template'
 111
 112         if RUBY_VERSION < '1.9.0'
 113           # Check whether we're called from an erb template.
 114           # We'd return a string in any other case, but erb <%= ... %>
 115           # can't take an <% end %> later on, so we have to use <% ... %>
 116           # and implicitly concat.
 117           def block_called_from_erb?(block)
 118             block && eval(BLOCK_CALLED_FROM_ERB, block)
 119           end
 120         else
 121           def block_called_from_erb?(block)
 122             block && eval(BLOCK_CALLED_FROM_ERB, block.binding)
 123           end
 124         end
 125
 126         def content_tag_string(name, content, options, escape = true)
 127           tag_options = tag_options(options, escape) if options
 128           "<#{name}#{tag_options}>#{content}</#{name}>"
 129         end
 130
 131         def tag_options(options, escape = true)
 132           unless options.blank?
 133             attrs = []
 134             if escape
 135               options.each_pair do |key, value|
 136                 if BOOLEAN_ATTRIBUTES.include?(key)
 137                   attrs << %(#{key}="#{key}") if value
 138                 else
 139                   attrs << %(#{key}="#{escape_once(value)}") if !value.nil?
 140                 end
 141               end
 142             else
 143               attrs = options.map { |key, value| %(#{key}="#{value}") }
 144             end
 145             " #{attrs.sort * ' '}" unless attrs.empty?
 146           end
 147         end
 148     end
 149   end
 150 end