Individual content types for multi form upload

When uploading multiple files through the form upload middleware
it would take the first file's content type and encoding and wrongly
apply it to all the uploaded files.

This was because there was a shared 'attributes' dict for all body parts
which was (correctly) filled from all the non-file parts. The file parts
however would also set their 'Content-Type' and 'Content-Encoding'
header values in the attributes dict.

The content type/encoding handling made sure to not overwrite
existing values in the dict. Thus the first file to specify such a
header value would win.

Now the individual files get their own content types/encodings by
applying the file part content type/encoding headers only to a copy
of the dict.

The file parts' headers continue to be ignored if they are overridden
by explicit 'content-type'/'content-encoding' body parts.

Closes-Bug: #1916017
Change-Id: I0a921afc481ef5b98cd5974c45d4b1d3e2a15731

swift/common/middleware/formpost.py

@@ -267,6 +267,7 @@ class FormPost(object):
             boundary = boundary.encode('utf-8')
         status = message = ''
         attributes = {}
+        file_attributes = {}
         subheaders = []
         file_count = 0
         for fp in iter_multipart_mime_documents(
@@ -283,15 +284,17 @@ class FormPost(object):
                         break
                 except ValueError:
                     raise FormInvalid('max_file_count not an integer')
-                attributes['filename'] = attrs['filename'] or 'filename'
+                file_attributes = attributes.copy()
+                file_attributes['filename'] = attrs['filename'] or 'filename'
                 if 'content-type' not in attributes and 'content-type' in hdrs:
-                    attributes['content-type'] = \
+                    file_attributes['content-type'] = \
                         hdrs['Content-Type'] or 'application/octet-stream'
                 if 'content-encoding' not in attributes and \
                         'content-encoding' in hdrs:
-                    attributes['content-encoding'] = hdrs['Content-Encoding']
+                    file_attributes['content-encoding'] = \
+                        hdrs['Content-Encoding']
                 status, subheaders = \
-                    self._perform_subrequest(env, attributes, fp, keys)
+                    self._perform_subrequest(env, file_attributes, fp, keys)
                 if not status.startswith('2'):
                     break
             else:

test/unit/common/middleware/test_formpost.py

@@ -2036,6 +2036,68 @@ class TestFormPost(unittest.TestCase):
         self.assertEqual("gzip",
                          self.app.requests[1].headers["Content-Encoding"])
 
+    def test_multiple_content_type_encoding(self):
+        body_part = [
+            '------WebKitFormBoundaryNcxTqxSlX7t4TDkR',
+            'Content-Disposition: form-data; name="file4"; '
+            'filename="testfile4.txt"',
+            'Content-Type: application/json',
+            '',
+            '{"four": 4}\n',
+        ]
+        if six.PY3:
+            body_part = [line.encode('utf-8') for line in body_part]
+
+        key = b'abc'
+        sig, env, body = self._make_sig_env_body(
+            '/v1/AUTH_test/container', '', 1024, 10, int(time() + 86400), key)
+        # splice in another file with a different content type
+        before_closing_boundary = len(body) - 2
+        body[before_closing_boundary:before_closing_boundary] = body_part
+        wsgi_input = b'\r\n'.join(body)
+        env['wsgi.input'] = BytesIO(wsgi_input)
+
+        env['swift.infocache'][get_cache_key('AUTH_test')] = (
+            self._fake_cache_env('AUTH_test', [key]))
+        env['swift.infocache'][get_cache_key(
+            'AUTH_test', 'container')] = {'meta': {}}
+        self.app = FakeApp(iter([('201 Created', {}, b'')] * 3))
+        self.auth = tempauth.filter_factory({})(self.app)
+        self.formpost = formpost.filter_factory({})(self.auth)
+        status = [None]
+        headers = [None]
+
+        def start_response(s, h, e=None):
+            status[0] = s
+            headers[0] = h
+
+        body = b''.join(self.formpost(env, start_response))
+        status = status[0]
+        headers = headers[0]
+        self.assertEqual(status, '201 Created')
+        self.assertTrue(b'201 Created' in body)
+
+        self.assertEqual(len(self.app.requests), 3)
+        self.assertEqual(self.app.requests[0].body, b'Test File\nOne\n')
+        self.assertEqual(self.app.requests[1].body, b'Test\nFile\nTwo\n')
+        self.assertEqual(self.app.requests[2].body, b'{"four": 4}\n')
+
+        self.assertIn("Content-Type", self.app.requests[0].headers)
+        self.assertIn("Content-Type", self.app.requests[1].headers)
+        self.assertIn("Content-Type", self.app.requests[2].headers)
+        self.assertEqual("text/plain",
+                         self.app.requests[0].headers["Content-Type"])
+        self.assertEqual("text/plain",
+                         self.app.requests[1].headers["Content-Type"])
+        self.assertEqual("application/json",
+                         self.app.requests[2].headers["Content-Type"])
+
+        self.assertFalse("Content-Encoding" in self.app.requests[0].headers)
+        self.assertIn("Content-Encoding", self.app.requests[1].headers)
+        self.assertEqual("gzip",
+                         self.app.requests[1].headers["Content-Encoding"])
+        self.assertFalse("Content-Encoding" in self.app.requests[2].headers)
+
 
 if __name__ == '__main__':
     unittest.main()