1 files changed, 27 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/json/encoders/string.rb b/activesupport/lib/active_support/json/encoders/string.rb
new file mode 100644
index 0000000000..707298d987
--- /dev/null
+++ b/activesupport/lib/active_support/json/encoders/string.rb
@@ -0,0 +1,27 @@
+module ActiveSupport
+  module JSON
+    module Encoding
+      ESCAPED_CHARS = {
+        "\010" =>  '\b',
+        "\f" =>    '\f',
+        "\n" =>    '\n',
+        "\r" =>    '\r',
+        "\t" =>    '\t',
+        '"' =>     '\"',
+        '\\' =>    '\\\\'
+      }
+    end
+  end
+end
+
+class String
+  def to_json #:nodoc:
+    '"' + gsub(/[\010\f\n\r\t"\\]/) { |s|
+      ActiveSupport::JSON::Encoding::ESCAPED_CHARS[s]
+    }.gsub(/([\xC0-\xDF][\x80-\xBF]|
+             [\xE0-\xEF][\x80-\xBF]{2}|
+             [\xF0-\xF7][\x80-\xBF]{3})+/nx) { |s|
+      s.unpack("U*").pack("n*").unpack("H*")[0].gsub(/.{4}/, '\\\\u\&')
+    } + '"'
+  end
+end