Added swift3.Response

Swift normalizes response headers with Python's str.title().  However, there
are some S3 clients who don't accept such kind of headers.  For example, AWS
Java SDK expects that a etag header is 'ETag', not 'Etag'.

This patch introduce our own Response class, which inherits swob.Response.  The
main differences from the original class are:

 - Normalizes response headers as S3 clients expect.
 - Replaces Swift specific headers like 'x-object-meta' with S3's ones.

Change-Id: I4a4443fc0b75e75ea7e2e45eede43f12b040a7a3

swift3/middleware.py

@@ -63,7 +63,8 @@ import datetime
 import re
 
 from swift.common.utils import get_logger
-from swift.common.swob import Request, Response, HTTPForbidden, HTTPConflict, \
+from swift.common.swob import Request
+from swift3.response import Response, HTTPForbidden, HTTPConflict, \
     HTTPBadRequest, HTTPMethodNotAllowed, HTTPNotFound, HTTPNotImplemented, \
     HTTPLengthRequired, HTTPServiceUnavailable, HTTPNoContent, HTTPOk
 from swift.common.http import HTTP_OK, HTTP_CREATED, HTTP_ACCEPTED, \
@@ -439,11 +440,6 @@ class BucketController(Controller):
         if status == HTTP_NO_CONTENT:
                 status = HTTP_OK
 
-        if 'x-container-object-count' in headers:
-            headers['x-rgw-object-count'] = headers['x-container-object-count']
-        if 'x-container-bytes-used' in headers:
-            headers['x-rgw-bytes-used'] = headers['x-container-bytes-used']
-
         return Response(status=status, headers=headers, app_iter=resp.app_iter)
 
     def GET(self, req):
@@ -591,16 +587,7 @@ class ObjectController(Controller):
             resp.app_iter = None
 
         if is_success(status):
-            new_hdrs = {}
-            for key, val in headers.iteritems():
-                _key = key.lower()
-                if _key.startswith('x-object-meta-'):
-                    new_hdrs['x-amz-meta-' + key[14:]] = val
-                elif _key in ('content-length', 'content-type',
-                              'content-range', 'content-encoding',
-                              'etag', 'last-modified'):
-                    new_hdrs[key] = val
-            return Response(status=status, headers=new_hdrs,
+            return Response(status=status, headers=headers,
                             app_iter=resp.app_iter)
         elif status in (HTTP_UNAUTHORIZED, HTTP_FORBIDDEN):
             return get_err_response('AccessDenied')

swift3/response.py

@@ -0,0 +1,129 @@
+# Copyright (c) 2014 OpenStack Foundation.
+#
+# 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.
+
+from functools import partial
+
+from swift.common import swob
+
+
+class HeaderKey(str):
+    """
+    A string object that normalizes string as S3 clients expect with title().
+    """
+    def title(self):
+        if self.lower() == 'etag':
+            # AWS Java SDK expects only 'ETag'.
+            return 'ETag'
+        if self.lower().startswith('x-amz-'):
+            # AWS headers returned by S3 are lowercase.
+            return self.lower()
+        if self.lower().startswith('x-rgw-'):
+            # ceph/s3tests expects the header is lowercase.
+            return self.lower()
+        return str.title(self)
+
+
+class HeaderKeyDict(swob.HeaderKeyDict):
+    """
+    Similar to the HeaderKeyDict class in Swift, but its key name is normalized
+    as S3 clients expect.
+    """
+    def __getitem__(self, key):
+        return swob.HeaderKeyDict.__getitem__(self, HeaderKey(key))
+
+    def __setitem__(self, key, value):
+        return swob.HeaderKeyDict.__setitem__(self, HeaderKey(key), value)
+
+    def __contains__(self, key):
+        return swob.HeaderKeyDict.__contains__(self, HeaderKey(key))
+
+    def __delitem__(self, key):
+        return swob.HeaderKeyDict.__delitem__(self, HeaderKey(key))
+
+    def get(self, key, default=None):
+        return swob.HeaderKeyDict.get(self, HeaderKey(key), default)
+
+    def pop(self, key, default=None):
+        return swob.HeaderKeyDict.pop(self, HeaderKey(key), default)
+
+
+class Response(swob.Response):
+    """
+    Similar to the Response class in Swift, but uses our HeaderKeyDict for
+    headers instead of Swift's HeaderKeyDict.  This also translates Swift
+    specific headers to S3 headers.
+    """
+    def __init__(self, *args, **kwargs):
+        swob.Response.__init__(self, *args, **kwargs)
+
+        headers = HeaderKeyDict()
+        for key, val in self.headers.iteritems():
+            _key = key.lower()
+            if _key.startswith('x-object-meta-'):
+                headers['x-amz-meta-' + key[14:]] = val
+            elif _key in ('content-length', 'content-type',
+                          'content-range', 'content-encoding',
+                          'etag', 'last-modified'):
+                headers[key] = val
+            elif _key == 'x-container-object-count':
+                # for ceph/s3tests
+                headers['x-rgw-object-count'] = val
+            elif _key == 'x-container-bytes-used':
+                # for ceph/s3tests
+                headers['x-rgw-bytes-used'] = val
+
+        self.headers = headers
+
+
+class StatusMap(object):
+    """
+    Similar to the StatusMap class in Swift, but returns swift3.Response
+    subclasses instead of swob.HTTPException.
+    """
+    def __getitem__(self, key):
+        return partial(Response, status=key)
+
+status_map = StatusMap()
+
+
+HTTPOk = status_map[200]
+HTTPCreated = status_map[201]
+HTTPAccepted = status_map[202]
+HTTPNoContent = status_map[204]
+HTTPMovedPermanently = status_map[301]
+HTTPFound = status_map[302]
+HTTPSeeOther = status_map[303]
+HTTPNotModified = status_map[304]
+HTTPTemporaryRedirect = status_map[307]
+HTTPBadRequest = status_map[400]
+HTTPUnauthorized = status_map[401]
+HTTPForbidden = status_map[403]
+HTTPMethodNotAllowed = status_map[405]
+HTTPNotFound = status_map[404]
+HTTPNotAcceptable = status_map[406]
+HTTPRequestTimeout = status_map[408]
+HTTPConflict = status_map[409]
+HTTPLengthRequired = status_map[411]
+HTTPPreconditionFailed = status_map[412]
+HTTPRequestEntityTooLarge = status_map[413]
+HTTPRequestedRangeNotSatisfiable = status_map[416]
+HTTPUnprocessableEntity = status_map[422]
+HTTPClientDisconnect = status_map[499]
+HTTPServerError = status_map[500]
+HTTPInternalServerError = status_map[500]
+HTTPNotImplemented = status_map[501]
+HTTPBadGateway = status_map[502]
+HTTPServiceUnavailable = status_map[503]
+HTTPInsufficientStorage = status_map[507]