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

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