Merge pull request #4433 from carlosantoniodasilva/html-escape-once

Html escape once

2 files changed, 20 insertions, 1 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 5df3ec406f..ad9a12fc9b 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*    Add html_escape_once to ERB::Util, and delegate escape_once tag helper to it. *Carlos Antonio da Silva*
+
 *    Remove ActiveSupport::TestCase#pending method, use `skip` instead. *Carlos Antonio da Silva*
 
 *    Deprecates the compatibility method Module#local_constant_names,
diff --git a/activesupport/lib/active_support/core_ext/string/output_safety.rb b/activesupport/lib/active_support/core_ext/string/output_safety.rb
index 73aa7dd89a..104ee251de 100644
--- a/activesupport/lib/active_support/core_ext/string/output_safety.rb
+++ b/activesupport/lib/active_support/core_ext/string/output_safety.rb
@@ -5,6 +5,8 @@ class ERB
   module Util
     HTML_ESCAPE = { '&' => '&amp;',  '>' => '&gt;',   '<' => '&lt;', '"' => '&quot;' }
     JSON_ESCAPE = { '&' => '\u0026', '>' => '\u003E', '<' => '\u003C' }
+    HTML_ESCAPE_ONCE_REGEXP = /[\"><]|&(?!([a-zA-Z]+|(#\d+));)/
+    JSON_ESCAPE_REGEXP = /[&"><]/
 
     # A utility method for escaping HTML tag characters.
     # This method is also aliased as <tt>h</tt>.
@@ -33,6 +35,21 @@ class ERB
     singleton_class.send(:remove_method, :html_escape)
     module_function :html_escape
 
+    # Returns an escaped version of +html+ without affecting existing escaped entities.
+    #
+    # ==== Examples
+    #   html_escape_once("1 < 2 &amp; 3")
+    #   # => "1 &lt; 2 &amp; 3"
+    #
+    #   html_escape_once("&lt;&lt; Accept & Checkout")
+    #   # => "&lt;&lt; Accept &amp; Checkout"
+    def html_escape_once(s)
+      result = s.to_s.gsub(HTML_ESCAPE_ONCE_REGEXP) { |special| HTML_ESCAPE[special] }
+      s.html_safe? ? result.html_safe : result
+    end
+
+    module_function :html_escape_once
+
     # A utility method for escaping HTML entities in JSON strings
     # using \uXXXX JavaScript escape sequences for string literals:
     #
@@ -51,7 +68,7 @@ class ERB
     #   <%=j @person.to_json %>
     #
     def json_escape(s)
-      result = s.to_s.gsub(/[&"><]/) { |special| JSON_ESCAPE[special] }
+      result = s.to_s.gsub(JSON_ESCAPE_REGEXP) { |special| JSON_ESCAPE[special] }
       s.html_safe? ? result.html_safe : result
     end