Invalid 'Called AE Title' value 'LWPACS' - must not contain control characters or backslashes

python3 -m pynetdicom echoscu 10.10.10.120 4445 -aec LWPACS -aet ydcfserver

E: Invalid 'Called AE Title' value 'LWPACS' - must not contain control characters or backslashes
E: State Machine received an exception attempting to perform the action 'AE-3' while in state 'Sta5'
E: Invalid 'Called AE Title' value 'LWPACS' - must not contain control characters or backslashes
Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/pynetdicom/fsm.py", line 90, in do_action
    next_state = action[1](self.dul)
  File "/usr/local/lib/python3.9/site-packages/pynetdicom/fsm.py", line 232, in AE_3
    dul.to_user_queue.put(cast("A_ASSOCIATE", pdu.to_primitive()))
  File "/usr/local/lib/python3.9/site-packages/pynetdicom/pdu.py", line 899, in to_primitive
    primitive.called_ae_title = self.reserved_aet
  File "/usr/local/lib/python3.9/site-packages/pynetdicom/pdu_primitives.py", line 206, in called_ae_title
    str, set_ae(value, "Called AE Title", False, False)
  File "/usr/local/lib/python3.9/site-packages/pynetdicom/utils.py", line 199, in set_ae
    raise ValueError(msg)
ValueError: Invalid 'Called AE Title' value 'LWPACS' - must not contain control characters or backslashes
Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/local/lib/python3.9/threading.py", line 973, in _bootstrap_inner
    self.run()
  File "/usr/local/lib/python3.9/threading.py", line 910, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/local/lib/python3.9/site-packages/pynetdicom/dul.py", line 445, in run_reactor
    self.state_machine.do_action(event)
  File "/usr/local/lib/python3.9/site-packages/pynetdicom/fsm.py", line 90, in do_action
    next_state = action[1](self.dul)
  File "/usr/local/lib/python3.9/site-packages/pynetdicom/fsm.py", line 232, in AE_3
    dul.to_user_queue.put(cast("A_ASSOCIATE", pdu.to_primitive()))
  File "/usr/local/lib/python3.9/site-packages/pynetdicom/pdu.py", line 899, in to_primitive
    primitive.called_ae_title = self.reserved_aet
  File "/usr/local/lib/python3.9/site-packages/pynetdicom/pdu_primitives.py", line 206, in called_ae_title
    str, set_ae(value, "Called AE Title", False, False)
  File "/usr/local/lib/python3.9/site-packages/pynetdicom/utils.py", line 199, in set_ae
    raise ValueError(msg)
ValueError: Invalid 'Called AE Title' value 'LWPACS' - must not contain control characters or backslashes

‘LWPACS’ is not contains control characters or backslashes, why valid error?

[mtoloon]

The K-PACS sends the AE-Title with trailing \x00, but the default validator doesn’t accept it.:
SPAX\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00

I fixed it by replacing the validator and remove the leading zero characters:
pynetdicom._config.VALIDATORS['AE'] = lambda x: pynetdicom._validators.validate_ae(x.strip(chr(0)))

Other clients such as dcm4chee doesn’t add \x00 padding

[scaramallion]

Hmm, I guess I could strip out nulls and warn instead of failing the validation.

Although doing so breaks the whole validator concept…

And I can’t leave nulls in because

>>> "foo" == "foo\0"
False