We need a different approach to preserve query string parameters

src/ZPublisher/HTTPRequest.py

@@ -497,23 +497,8 @@ def processInputs(
             environ['QUERY_STRING'] = ''
 
         meth = None
-
-        # Workaround for https://bugs.python.org/issue27777:
-        # If Content-Length is nonzero, manufacture a Content-Disposition
-        # with a filename to make sure a binary file is opened.
-        headers = None
-        if 'CONTENT_LENGTH' in environ and environ['CONTENT_LENGTH'] != '0':
-            # In order to override content-disposition we need to
-            # specify the full headers; this is based on FileStorage.__init__
-            headers = {
-                'content-type': 'application/x-www-form-urlencoded'
-            }
-            if 'CONTENT_TYPE' in environ:
-                headers['content-type'] = environ['CONTENT_TYPE']
-            headers['content-length'] = environ['CONTENT_LENGTH']
-            headers['content-disposition'] = 'inline; filename="stdin"'
-        fs = FieldStorage(
-            fp=fp, headers=headers, environ=environ, keep_blank_values=1)
+        fs = ZopeFieldStorage(
+            fp=fp, environ=environ, keep_blank_values=1)
 
         # Keep a reference to the FieldStorage. Otherwise it's
         # __del__ method is called too early and closing FieldStorage.file.
@@ -1643,7 +1628,15 @@ def sane_environment(env):
     return dict
 
 
-ZopeFieldStorage = FieldStorage  # BBB
+class ZopeFieldStorage(FieldStorage):
+    """This subclass exists to work around a Python bug
+    (see https://bugs.python.org/issue27777) to make sure
+    we can read binary data from a request body.
+    """
+
+    def read_binary(self):
+        self._binary_file = True
+        return super(ZopeFieldStorage, self).read_binary()
 
 
 # Original version: zope.publisher.browser.FileUpload

src/ZPublisher/tests/testHTTPRequest.py

@@ -778,6 +778,19 @@ def test_processInputs_xmlrpc(self):
         self.assertEqual(req.PATH_INFO, '/test')
         self.assertEqual(req.args, ())
 
+    def test_processInputs_w_urlencoded_and_qs(self):
+        body = b'foo=1'
+        environ = {
+            'CONTENT_TYPE': 'application/x-www-form-urlencoded',
+            'CONTENT_LENGTH': len(body),
+            'QUERY_STRING': 'bar=2',
+            'REQUEST_METHOD': 'POST',
+        }
+        req = self._makeOne(stdin=BytesIO(body), environ=environ)
+        req.processInputs()
+        self.assertEqual(req.form['foo'], '1')
+        self.assertEqual(req.form['bar'], '2')
+
     def test_postProcessInputs(self):
         from ZPublisher.HTTPRequest import default_encoding