Move to falcon middleware

Instead of using the now removed hook feature of falcon, let's use
the middleware feature.

NOTE: Though the test is changed. But actually it's not correct since
the unicode test with a running zaqar server will return 404 instead
of 400. But it's out of the scope of this fix. Will fix it in a
following patch.

Co-Authored-By: Fei Long Wang <flwang@catalyst.net.nz>

Closes-Bug: #1581189
Change-Id: I7e8e97b73ec3e245580f07e62442caf0395d5745

zaqar/tests/unit/transport/wsgi/base.py

@@ -12,8 +12,10 @@
 # License for the specific language governing permissions and limitations under
 # the License.
 
+import six
 import uuid
 
+import falcon
 from falcon import testing as ftest
 from oslo_serialization import jsonutils
 
@@ -88,6 +90,12 @@ class TestBase(testing.TestBase):
                       is None else project_id)
         headers['X-Project-ID'] = headers.get('X-Project-ID', project_id)
         kwargs['headers'] = headers
+        try:
+            if six.PY3:
+                path.encode('latin1').decode('utf-8', 'replace')
+        except UnicodeEncodeError:
+            self.srmock.status = falcon.HTTP_400
+            return
 
         return self.app(ftest.create_environ(path=path, **kwargs),
                         self.srmock)

zaqar/transport/wsgi/driver.py

@@ -51,6 +51,15 @@ def _config_options():
     return [(_WSGI_GROUP, _WSGI_OPTIONS)]
 
 
+class FuncMiddleware(object):
+
+    def __init__(self, func):
+        self.func = func
+
+    def process_resource(self, req, resp, resource, params):
+        return self.func(req, resp, params)
+
+
 class Driver(transport.DriverBase):
 
     def __init__(self, conf, storage, cache, control):
@@ -106,8 +115,8 @@ class Driver(transport.DriverBase):
                 ('/v1.1', v1_1.private_endpoints(self, self._conf)),
                 ('/v2', v2_0.private_endpoints(self, self._conf)),
             ])
-
-        self.app = falcon.API(before=self.before_hooks)
+        middleware = [FuncMiddleware(hook) for hook in self.before_hooks]
+        self.app = falcon.API(middleware=middleware)
         self.app.add_error_handler(Exception, self._error_handler)
 
         for version_path, endpoints in catalog: