Don't patch Requests globally on import

This also upgrades the Requests dependency to 2.4+ (released in 2014)
to avoid having to do version comparisons altogether.

Refs https://bugs.launchpad.net/python-swiftclient/+bug/1904551

Signed-off-by: Aarni Koskela <akx@iki.fi>
Change-Id: I58399f6c526b0b78462f31739c43076314ba9e76

4 files changed, 62 insertions, 41 deletions

diff --git a/requirements.txt b/requirements.txt
index b7c9240..c802baa 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,3 @@
 
-requests>=1.1.0
+requests>=2.4.0
 six>=1.9.0
diff --git a/swiftclient/client.py b/swiftclient/client.py
index cc5478a..ddcf63a 100644
--- a/swiftclient/client.py
+++ b/swiftclient/client.py
@@ -18,11 +18,9 @@ OpenStack Swift client library used internally
 """
 import socket
 import re
-import requests
 import logging
 import warnings
 
-from distutils.version import StrictVersion
 from requests.exceptions import RequestException, SSLError
 from six.moves import http_client
 from six.moves.urllib.parse import quote as _quote, unquote
@@ -32,6 +30,7 @@ import six
 
 from swiftclient import version as swiftclient_version
 from swiftclient.exceptions import ClientException
+from swiftclient.requests_compat import SwiftClientRequestsSession
 from swiftclient.utils import (
     iter_wrapper, LengthWrapper, ReadableToIterable, parse_api_response,
     get_body)
@@ -64,20 +63,6 @@ try:
 except ImportError:
     pass
 
-# requests version 1.2.3 try to encode headers in ascii, preventing
-# utf-8 encoded header to be 'prepared'. This also affects all
-# (or at least most) versions of requests on py3
-if StrictVersion(requests.__version__) < StrictVersion('2.0.0') \
-        or not six.PY2:
-    from requests.structures import CaseInsensitiveDict
-
-    def prepare_unicode_headers(self, headers):
-        if headers:
-            self.headers = CaseInsensitiveDict(headers)
-        else:
-            self.headers = CaseInsensitiveDict()
-    requests.models.PreparedRequest.prepare_headers = prepare_unicode_headers
-
 logger = logging.getLogger("swiftclient")
 logger.addHandler(logging.NullHandler())
 
@@ -398,7 +383,7 @@ class HTTPConnection(object):
         self.host = self.parsed_url.netloc
         self.port = self.parsed_url.port
         self.requests_args = {}
-        self.request_session = requests.Session()
+        self.request_session = SwiftClientRequestsSession()
         # Don't use requests's default headers
         self.request_session.headers = None
         self.resp = None
@@ -1434,11 +1419,6 @@ def put_object(url, token=None, container=None, name=None, contents=None,
                 content_length = int(v)
     if content_type is not None:
         headers['Content-Type'] = content_type
-    elif 'Content-Type' not in headers:
-        if StrictVersion(requests.__version__) < StrictVersion('2.4.0'):
-            # python-requests sets application/x-www-form-urlencoded otherwise
-            # if using python3.
-            headers['Content-Type'] = ''
     if not contents:
         headers['Content-Length'] = '0'
 
diff --git a/swiftclient/requests_compat.py b/swiftclient/requests_compat.py
new file mode 100644
index 0000000..c2371b7
--- /dev/null
+++ b/swiftclient/requests_compat.py
@@ -0,0 +1,57 @@
+# Copyright (c) 2010-2022 OpenStack, LLC.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import requests
+from requests.sessions import merge_setting, merge_hooks
+from requests.structures import CaseInsensitiveDict
+
+
+class SwiftClientPreparedRequest(requests.PreparedRequest):
+    def prepare_headers(self, headers):
+        try:
+            return super().prepare_headers(headers)
+        except UnicodeError:
+            # If we got an unicode error from the superclass's prepare_headers,
+            # we had a non-spec-compliant non-ASCII header
+            # (e.g. an UTF-8 encoded Swift object metadata header).
+            # In that case, we just pass it through and hope nothing
+            # bad will happen from not following the HTTP spec.
+            self.headers = CaseInsensitiveDict(headers or {})
+
+
+class SwiftClientRequestsSession(requests.Session):
+
+    def prepare_request(self, request):
+        # Close to the superclass's implementation,
+        # but no cookies or .netrc authentication overrides here.
+        p = SwiftClientPreparedRequest()
+        headers = merge_setting(
+            request.headers,
+            self.headers,
+            dict_class=CaseInsensitiveDict,
+        )
+        p.prepare(
+            method=request.method.upper(),
+            url=request.url,
+            files=request.files,
+            data=request.data,
+            json=request.json,
+            headers=headers,
+            params=merge_setting(request.params, self.params),
+            auth=merge_setting(request.auth, self.auth),
+            cookies=None,
+            hooks=merge_hooks(request.hooks, self.hooks),
+        )
+        return p
diff --git a/test/unit/test_swiftclient.py b/test/unit/test_swiftclient.py
index f6dc258..6bdd6ad 100644
--- a/test/unit/test_swiftclient.py
+++ b/test/unit/test_swiftclient.py
@@ -1325,7 +1325,6 @@ class TestHeadObject(MockHttpTest):
 
 class TestPutObject(MockHttpTest):
 
-    @mock.patch('swiftclient.requests.__version__', '2.2.0')
     def test_ok(self):
         c.http_connection = self.fake_http_connection(200)
         args = ('http://www.test.com', 'TOKEN', 'container', 'obj', 'body', 4)
@@ -1336,7 +1335,6 @@ class TestPutObject(MockHttpTest):
             ('PUT', '/container/obj', 'body', {
                 'x-auth-token': 'TOKEN',
                 'content-length': '4',
-                'content-type': ''
             }),
         ])
 
@@ -1383,7 +1381,6 @@ class TestPutObject(MockHttpTest):
             self.assertEqual(len(w), 1)
             self.assertTrue(issubclass(w[-1].category, UserWarning))
 
-    @mock.patch('swiftclient.requests.__version__', '2.2.0')
     def test_server_error(self):
         body = 'c' * 60
         headers = {'foo': 'bar'}
@@ -1398,8 +1395,7 @@ class TestPutObject(MockHttpTest):
         self.assertEqual(e.http_status, 500)
         self.assertRequests([
             ('PUT', '/asdf/asdf', 'asdf', {
-                'x-auth-token': 'asdf',
-                'content-type': ''}),
+                'x-auth-token': 'asdf'}),
         ])
 
     def test_query_string(self):
@@ -1540,19 +1536,7 @@ class TestPutObject(MockHttpTest):
         self.assertEqual(request_header['etag'], b'1234-5678')
         self.assertEqual(request_header['content-type'], b'text/plain')
 
-    @mock.patch('swiftclient.requests.__version__', '2.2.0')
-    def test_no_content_type_old_requests(self):
-        conn = c.http_connection(u'http://www.test.com/')
-        resp = MockHttpResponse(status=200)
-        conn[1].getresponse = resp.fake_response
-        conn[1]._request = resp._fake_request
-
-        c.put_object(url='http://www.test.com', http_conn=conn)
-        request_header = resp.requests_params['headers']
-        self.assertEqual(request_header['content-type'], b'')
-
-    @mock.patch('swiftclient.requests.__version__', '2.4.0')
-    def test_no_content_type_new_requests(self):
+    def test_no_content_type_requests(self):
         conn = c.http_connection(u'http://www.test.com/')
         resp = MockHttpResponse(status=200)
         conn[1].getresponse = resp.fake_response