Add an attachments endpoint to stories

This endpoint currently supports returning an upload URL
for the configured storage backend.

Change-Id: I637cf5897f281a4e6b66be6495938aa999a8d3ac
Story: 2000679
Task: 29115

storyboard/api/v1/attachments.py

@@ -0,0 +1,56 @@
+# Copyright (c) 2019 Adam Coldrick
+#
+# 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 oslo_config import cfg
+from pecan import response
+from pecan import rest
+from pecan.secure import secure
+from wsme import types as wtypes
+import wsmeext.pecan as wsme_pecan
+
+from storyboard.api.auth import authorization_checks as checks
+from storyboard.api.v1.storage import storage
+
+
+CONF = cfg.CONF
+
+STORAGE_BACKEND = storage.get_storage_backend()
+
+
+class AttachmentsController(rest.RestController):
+    """Endpoint for managing attachments."""
+
+    _custom_actions = {"upload_url": ["GET"]}
+
+    @secure(checks.authenticated)
+    @wsme_pecan.wsexpose(wtypes.text, int)
+    def upload_url(self, story_id):
+        """Return a URL which can be used to upload attachments.
+
+        The storage type and authentication token are provided in the
+        X-Storage-Type and X-Auth-Token response headers respectively.
+
+        :param story_id: ID of the story the attachment is for.
+            Currently unused, and just needed for routing.
+
+        """
+        response.headers['X-Storage-Type'] = CONF.attachments.storage_backend
+
+        expiry, auth, name = STORAGE_BACKEND.get_auth()
+        response.headers['X-Auth-Token'] = auth
+        response.headers['X-Token-Expiry'] = str(expiry)
+        response.headers['X-Object-Name'] = name
+
+        return STORAGE_BACKEND.get_upload_url()

storyboard/api/v1/stories.py

@@ -28,6 +28,7 @@ import wsmeext.pecan as wsme_pecan
 
 from storyboard._i18n import _
 from storyboard.api.auth import authorization_checks as checks
+from storyboard.api.v1.attachments import AttachmentsController
 from storyboard.api.v1.search import search_engine
 from storyboard.api.v1.tags import TagsController
 from storyboard.api.v1.tasks import TasksNestedController
@@ -489,6 +490,8 @@ class StoriesController(rest.RestController):
         stories_api.story_delete(
             story_id, current_user=request.current_user_id)
 
+    if CONF.attachments.enable_attachments:
+        attachments = AttachmentsController()
     comments = CommentsController()
     events = NestedTimeLineEventsController()
     tasks = TasksNestedController()