diff -r 7d5f35326a77 -r 37549b5d1d29 Doc/library/urllib.request.rst
--- a/Doc/library/urllib.request.rst	Wed Nov 07 00:57:26 2012 +0100
+++ b/Doc/library/urllib.request.rst	Wed Nov 07 04:12:00 2012 +0100
@@ -1196,6 +1196,63 @@
    >>> f.read().decode('utf-8')
 
 
+.. _urllib-request-recipes:
+
+Recipes
+-------
+
+Data URLs aren't supported by :mod:`urllib.request` module. But adding support
+for them is easy, as this recipe shows. Note that many browsers allow base64
+encoded data URLs to skip any padding characters. This implementation is strict
+and raises an exception when this happens. ::
+
+   import binascii
+   import urllib.request
+   import urllib.parse
+   import email.message
+   import io
+
+   def parse_data_url(url):
+      scheme, data = url.split(":",1)
+      assert scheme == "data", "unsupported scheme: "+scheme
+      mediatype, data = data.split(",",1)
+      # base64 urls might have a padding which might be quoted:
+      data = urllib.parse.unquote_to_bytes(data)
+      if mediatype.endswith(";base64"):
+         return binascii.a2b_base64(data), mediatype[:-7] or None
+      else:
+         return data, mediatype or None
+
+   class DataResponse(io.BytesIO):
+      def __init__(self,url):
+         data, mediatype = parse_data_url(url)
+         io.BytesIO.__init__(self,data)
+         self.url = url
+         self.mediatype = mediatype
+         self.length = len(data)
+         self.headers = email.message.Message()
+         if mediatype is not None:
+            self.headers.add_header("Content-Type",mediatype)
+
+      def geturl(self):
+         return self.url
+
+      def info(self):
+         return self.headers
+
+   class DataHandler(urllib.request.BaseHandler):
+      def data_open(self, req):
+         return DataResponse(req.full_url)
+
+You can then install and use this protocol handler like so::
+
+   >>> from urllib.request import build_opener, install_opener, urlopen
+   >>> install_opener(build_opener(DataHandler))
+   >>> f = urlopen('data:text/plain;charset=utf-8;base64,SGVsbG8gV29ybGQhCg==')
+   >>> print(f.read())
+   b'Hello World!\n'
+
+
 Legacy interface
 ----------------