From 1a466d5c056bb6eee00cc4deb44a620342f6f80c Mon Sep 17 00:00:00 2001
From: Michael Thies <m.thies@plt.rwth-aachen.de>
Date: Thu, 5 Nov 2020 09:40:09 +0100
Subject: [PATCH] backends.couchdb: Improve discard(): Use HEAD request to
fetch current revision
---
aas/backend/couchdb.py | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/aas/backend/couchdb.py b/aas/backend/couchdb.py
index 7599a51d..5d289faa 100644
--- a/aas/backend/couchdb.py
+++ b/aas/backend/couchdb.py
@@ -342,7 +342,6 @@ class CouchDBObjectStore(model.AbstractObjectStore):
:raises CouchDBError: If error occur during the request to the CouchDB server (see `_do_request()` for details)
"""
logger.debug("Deleting object %s from CouchDB database ...", repr(x))
- # If x is not a CouchDBIdentifiable, retrieve x from the database to get the current couchdb_revision
rev = get_couchdb_revision("{}/{}/{}".format(self.url,
self.database_name,
self._transform_id(x.identification)))
@@ -352,18 +351,22 @@ class CouchDBObjectStore(model.AbstractObjectStore):
elif safe_delete:
raise CouchDBConflictError("No CouchDBRevision found for the object")
else:
+ # If not safe_delete, fetch the current document revision from the database using a HEAD request and the
+ # ETag response header
try:
logger.debug("fetching the current object revision for deletion ...")
request = urllib.request.Request(
"{}/{}/{}".format(self.url, self.database_name, self._transform_id(x.identification)),
- headers={'Accept': 'application/json'})
- current_data = CouchDBBackend.do_request(request)
- except CouchDBServerError as e:
+ headers={'Accept': 'application/json'},
+ method='HEAD')
+ opener = urllib.request.build_opener(urllib.request.HTTPBasicAuthHandler(_credentials_store))
+ response = opener.open(request)
+ rev = response.getheader('ETag')[1:-1]
+ except urllib.error.HTTPError as e:
if e.code == 404:
raise KeyError("No AAS object with id {} exists in CouchDB database".format(x.identification))\
from e
raise
- rev = current_data['_rev']
request = urllib.request.Request(
"{}/{}/{}?rev={}".format(self.url, self.database_name, self._transform_id(x.identification), rev),
--
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