--- a/wsgi/request.py	Tue Sep 02 13:00:47 2014 +0200
+++ b/wsgi/request.py	Mon Sep 08 10:55:30 2014 +0200
@@ -30,6 +30,7 @@
 from StringIO import StringIO
 from urllib import quote
 from urlparse import parse_qs
+from warnings import warn
 
 from cubicweb.multipart import copy_file, parse_form_data
 from cubicweb.web.request import CubicWebRequestBase
@@ -152,6 +153,38 @@
         if self.method == 'POST':
             forms, files = parse_form_data(self.environ, strict=True,
                                            mem_limit=self.vreg.config['max-post-length'])
-            post.update(forms)
+            post.update(forms.dict)
         self.content.seek(0, 0)
         return post, files
+
+    def setup_params(self, params):
+        # This is a copy of CubicWebRequestBase.setup_params, but without
+        # converting unicode strings because it is partially done by
+        # get_posted_data
+        self.form = {}
+        if params is None:
+            return
+        encoding = self.encoding
+        for param, val in params.iteritems():
+            if isinstance(val, (tuple, list)):
+                val = [
+                    unicode(x, encoding) if isinstance(x, str) else x
+                    for x in val]
+                if len(val) == 1:
+                    val = val[0]
+            elif isinstance(val, str):
+                val = unicode(val, encoding)
+            if param in self.no_script_form_params and val:
+                val = self.no_script_form_param(param, val)
+            if param == '_cwmsgid':
+                self.set_message_id(val)
+            elif param == '__message':
+                warn('[3.13] __message in request parameter is deprecated (may '
+                     'only be given to .build_url). Seeing this message usualy '
+                     'means your application hold some <form> where you should '
+                     'replace use of __message hidden input by form.set_message, '
+                     'so new _cwmsgid mechanism is properly used',
+                     DeprecationWarning)
+                self.set_message(val)
+            else:
+                self.form[param] = val

--- a/wsgi/test/unittest_wsgi.py	Tue Sep 02 13:00:47 2014 +0200
+++ b/wsgi/test/unittest_wsgi.py	Mon Sep 08 10:55:30 2014 +0200
@@ -64,6 +64,18 @@
             '/',
             params={'__login': self.admlogin, '__password': self.admpassword})
 
+    def test_get_multiple_variables(self):
+        r = webtest.app.TestRequest.blank('/?arg=1&arg=2')
+        req = CubicWebWsgiRequest(r.environ, self.vreg)
+
+        self.assertEqual([u'1', u'2'], req.form['arg'])
+
+    def test_post_multiple_variables(self):
+        r = webtest.app.TestRequest.blank('/', POST='arg=1&arg=2')
+        req = CubicWebWsgiRequest(r.environ, self.vreg)
+
+        self.assertEqual([u'1', u'2'], req.form['arg'])
+
     @classmethod
     def init_config(cls, config):
         super(WSGIAppTC, cls).init_config(config)