From 81d9428eca0b831d52e42c6ed8ac001b4dc8adff Mon Sep 17 00:00:00 2001
From: thedarkone <nobody>
Date: Thu, 26 Feb 2009 01:23:24 +0100
Subject: [PATCH] Implement url safe "base64url" encoding (RFC 4648).

---
 .../lib/active_support/core_ext/base64/encoding.rb |   31 ++++++++++++++++++++
 activesupport/test/core_ext/base64_ext_test.rb     |   14 +++++++++
 2 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/activesupport/lib/active_support/core_ext/base64/encoding.rb b/activesupport/lib/active_support/core_ext/base64/encoding.rb
index a9656c1..589659e 100644
--- a/activesupport/lib/active_support/core_ext/base64/encoding.rb
+++ b/activesupport/lib/active_support/core_ext/base64/encoding.rb
@@ -10,6 +10,37 @@ module ActiveSupport #:nodoc:
         def encode64s(value)
           encode64(value).gsub(/\n/, '')
         end
+
+        B2URL_PATTERN     = '+/='
+        B2URL_REPLACEMENT = '-_ '
+
+        URL2B_PATTERN     = '-_'
+        URL2B_REPLACEMENT = '+/'
+
+        # Encodes passed data using "base64url" (as defined by RFC4648). This makes the base64 encoding readily usable as URL parameters
+        # not requiring percent-encoding. No padding '=' or newline breaks are used, and the '+' and '/' characters of standard Base64 
+        # encoding are respectively replaced by '-' and '_'.
+        # ==== Examples
+        #   ActiveSupport::Base64.encode64("\377\377\276a") # => "//++YQ==\n"
+        #   ActiveSupport::Base64.encode64_url("\377\377\276a") # => "__--YQ"
+        #   ActiveSupport::Base64.decode64_url("__--YQ") # => "\377\377\276a"
+        def encode64_url(data)
+          encode64(data).tr(B2URL_PATTERN, B2URL_REPLACEMENT).strip.delete("\n")
+        end
+
+        # Decodes a "base64url" encoded string to its original representation.
+        # See <tt>Encoding#encode64_url</tt> for more information.
+        def decode64_url(str)
+          # add '=' padding
+          str = case str.length % 4
+            when 2 then str + '=='
+            when 3 then str + '='
+            else
+              str
+          end
+
+          decode64(str.tr(URL2B_PATTERN, URL2B_REPLACEMENT))
+        end
       end
     end
   end
diff --git a/activesupport/test/core_ext/base64_ext_test.rb b/activesupport/test/core_ext/base64_ext_test.rb
index bd0e9f8..b27a94b 100644
--- a/activesupport/test/core_ext/base64_ext_test.rb
+++ b/activesupport/test/core_ext/base64_ext_test.rb
@@ -5,4 +5,18 @@ class Base64Test < Test::Unit::TestCase
     assert_match(/\n/,    ActiveSupport::Base64.encode64("oneverylongstringthatwouldnormallybesplitupbynewlinesbytheregularbase64"))
     assert_no_match(/\n/, ActiveSupport::Base64.encode64s("oneverylongstringthatwouldnormallybesplitupbynewlinesbytheregularbase64"))
   end
+
+  def test_base64url_works
+    problematic_input = "\377\377\276a"
+    assert_equal "//++YQ==\n",      ActiveSupport::Base64.encode64(problematic_input)
+    assert_equal '__--YQ',          ActiveSupport::Base64.encode64_url(problematic_input)
+    assert_equal problematic_input, ActiveSupport::Base64.decode64_url('__--YQ')
+    assert_equal problematic_input, ActiveSupport::Base64.decode64_url('__--YQ==')
+  end
+
+  def test_decode64_url_does_not_modify_its_input
+    str = '//++YQ'
+    ActiveSupport::Base64.decode64_url(str)
+    assert_equal '//++YQ', str
+  end
 end
-- 
1.6.0.1