def add_nonce(cls, actor_id, nonce):
"""
Atomically append a new nonce to the nonce_store for an actor.
The actor_id parameter should be the db_id and the nonce parameter should be a nonce object
created from the contructor.
"""
try:
nonce_store.update(actor_id, nonce.id, nonce)
logger.debug("nonce {} appended to nonces for actor {}".format(nonce.id, actor_id))
except KeyError:
nonce_store[actor_id] = {nonce.id: nonce}
logger.debug("nonce {} added for actor {}".format(nonce.id, actor_id))
def _transaction(nonces):
"""
This function can be passed to nonce_store.within_transaction() to atomically check
whether a nonce is expired and, if not, redeem a use. The parameter, nonces, should
be the value under the key `actor_id` associated with the nonce.
"""
# first pull the nonce from the nonces parameter
try:
nonce = nonces[nonce_id]
except KeyError:
raise errors.PermissionsException("Nonce does not exist.")
# check if the nonce level is sufficient
try:
if PermissionLevel(nonce['level']) < level:
raise errors.PermissionsException(
"Nonce does not have sufficient permissions level.")
except KeyError:
raise errors.PermissionsException(
"Nonce did not have an associated level.")
# check if there are remaining uses
try:
if nonce['remaining_uses'] == -1:
logger.debug("nonce has infinite uses. updating nonce.")
nonce['current_uses'] += 1
nonce['last_use_time'] = get_current_utc_time()
nonce_store.update(actor_id, nonce_id, nonce)
elif nonce['remaining_uses'] > 0:
logger.debug(
"nonce still has uses remaining. updating nonce.")
nonce['current_uses'] += 1
nonce['remaining_uses'] -= 1
nonce_store.update(actor_id, nonce_id, nonce)
else:
logger.debug(
"nonce did not have at least 1 use remaining.")
raise errors.PermissionsException(
"No remaining uses left for this nonce.")
except KeyError:
logger.debug("nonce did not have a remaining_uses attribute.")
raise errors.PermissionsException(
"No remaining uses left for this nonce.")