def get_devices(self, refresh=False):
if self.cache:
if refresh is True or not Cache.get(self.cache):
result = self._get_devices()
Cache.set(self.cache, result)
else:
result = Cache.get(self.cache)
else:
result = self._get_devices()
return result
def authenticate_credentials(self, credentials):
decoded_auth = b64decode(credentials)
client_id, _, signature = decoded_auth.partition(':')
client = Client.objects.filter(pk=client_id).first()
if client is None:
raise Unauthorized
timestamp_header = os.getenv('HMAC_TIMESTAMP_HEADER', 'Timestamp')
nonce_header = os.getenv('HMAC_NONCE_HEADER', 'Nonce')
timestamp = request.headers.get(timestamp_header)
nonce = request.headers.get(nonce_header)
msg = "{method}{path}{payload}{timestamp}{nonce}".format(
method=request.method,
path=request.path,
payload=request.data,
timestamp=timestamp,
nonce=nonce)
digest = hmac.HMAC(key=client.secret.encode(),
msg=msg.encode(),
digestmod=sha256)
calculated_signature = b64encode(digest).decode()
if signature != calculated_signature:
raise Unauthorized
hmac_expires = int(os.getenv('HMAC_EXPIRES', 60 * 5))
timestamp = float(timestamp)
if time.time() - timestamp > hmac_expires:
raise Unauthorized
cache = Cache(key_prefix='nonce')
if nonce in cache:
raise Unauthorized
cache.set(nonce, True, timeout=hmac_expires)
return client
