From 5bdf1da730368a16beaa077d91457ff625f06bc4 Mon Sep 17 00:00:00 2001
From: Adrian Holovaty <adrian@holovaty.com>
Date: Fri, 2 Sep 2005 19:39:47 +0000
Subject: [PATCH] Fixed #394 -- Trailing-slash redirects now retain duplicate
 name-value query-string pairs, instead of the first of each pair. Added a
 QueryDict.urlencode() method to accomplish this. Updated the docs. Thanks for
 the good catch, mlambert

git-svn-id: http://code.djangoproject.com/svn/django/trunk@613 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
 django/middleware/common.py  |  3 +--
 django/utils/httpwrappers.py |  7 +++++++
 docs/request_response.txt    | 30 +++++++++++++++++++++---------
 3 files changed, 29 insertions(+), 11 deletions(-)

diff --git a/django/middleware/common.py b/django/middleware/common.py
index 295855d73e..ee6b68be7e 100644
--- a/django/middleware/common.py
+++ b/django/middleware/common.py
@@ -4,7 +4,6 @@ from django.utils import httpwrappers
 from django.core.mail import mail_managers
 from django.views.core.flatfiles import flat_file
 import md5, os
-from urllib import urlencode
 
 class CommonMiddleware:
     """
@@ -49,7 +48,7 @@ class CommonMiddleware:
             # Redirect
             newurl = "%s://%s%s" % (os.environ.get('HTTPS') == 'on' and 'https' or 'http', new_url[0], new_url[1])
             if request.GET:
-                newurl += '?' + urlencode(request.GET)
+                newurl += '?' + request.GET.urlencode()
             return httpwrappers.HttpResponseRedirect(newurl)
 
         return None
diff --git a/django/utils/httpwrappers.py b/django/utils/httpwrappers.py
index 4a648d1849..107b63d40b 100644
--- a/django/utils/httpwrappers.py
+++ b/django/utils/httpwrappers.py
@@ -1,5 +1,6 @@
 from Cookie import SimpleCookie
 from pprint import pformat
+from urllib import urlencode
 import datastructures
 
 DEFAULT_MIME_TYPE = 'text/html'
@@ -117,6 +118,12 @@ class QueryDict(datastructures.MultiValueDict):
         self.assert_synchronized()
         return self._keys
 
+    def urlencode(self):
+        output = []
+        for k, list_ in self.data.items():
+            output.extend([urlencode({k: v}) for v in list_])
+        return '&'.join(output)
+
 def parse_cookie(cookie):
     if cookie == '':
         return {}
diff --git a/docs/request_response.txt b/docs/request_response.txt
index 3f4ccea713..a004b99126 100644
--- a/docs/request_response.txt
+++ b/docs/request_response.txt
@@ -115,16 +115,20 @@ Methods
 
     Example: ``"/music/bands/the_beatles/?print=true"``
 
-MultiValueDict objects
-----------------------
+QueryDict objects
+-----------------
 
 In an ``HttpRequest`` object, the ``GET`` and ``POST`` attributes are instances
-of ``django.utils.datastructures.MultiValueDict``. ``MultiValueDict`` is a
-dictionary-like class customized to deal with multiple values for the same key.
-This is necessary because some HTML form elements, notably
-``<select multiple>``, pass multiple values for the same key.
+of ``django.utils.httpwrappers.QueryDict``. ``QueryDict`` is a dictionary-like
+class customized to deal with multiple values for the same key. This is
+necessary because some HTML form elements, notably ``<select multiple>``, pass
+multiple values for the same key.
 
-``MultiValueDict`` implements the following standard dictionary methods:
+``QueryDict`` instances are immutable, unless you create a ``copy()`` of them.
+That means you can't change attributes of ``request.POST`` and ``request.GET``
+directly.
+
+``QueryDict`` implements the following standard dictionary methods:
 
     * ``__repr__()``
 
@@ -141,7 +145,11 @@ This is necessary because some HTML form elements, notably
 
     * ``has_key(key)``
 
-    * ``items()``
+    * ``items()`` -- Just like the standard dictionary ``items()`` method,
+      except this retains the order for values of duplicate keys, if any. For
+      example, if the original query string was ``"a=1&b=2&b=3"``, ``items()``
+      will return ``[("a", ["1"]), ("b", ["2", "3"])]``, where the order of
+      ``["2", "3"]`` is guaranteed, but the order of ``a`` vs. ``b`` isn't.
 
     * ``keys()``
 
@@ -150,7 +158,8 @@ This is necessary because some HTML form elements, notably
 In addition, it has the following methods:
 
     * ``copy()`` -- Returns a copy of the object, using ``copy.deepcopy()``
-      from the Python standard library.
+      from the Python standard library. The copy will be mutable -- that is,
+      you can change its values.
 
     * ``getlist(key)`` -- Returns the data with the requested key, as a Python
       list. Returns an empty list if the key doesn't exist.
@@ -161,6 +170,9 @@ In addition, it has the following methods:
     * ``appendlist(key, item)`` -- Appends an item to the internal list
       associated with key.
 
+    * ``urlencode()`` -- Returns a string of the data in query-string format.
+      Example: ``"a=2&b=3&b=5"``.
+
 Examples
 --------