[BUG] SOAP Error in PullMessages

[gustavofuhr]

Describe the bug
I'm getting the following error when trying to PullMessages before a successfull connection:

Traceback (most recent call last):
  File "/home/gfuhr/projects/immediate-action-prototypes/onvif/.onvif/lib/python3.12/site-packages/onvif/operator.py", line 201, in call
    result = func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "/home/gfuhr/projects/immediate-action-prototypes/onvif/.onvif/lib/python3.12/site-packages/zeep/proxy.py", line 46, in __call__
    return self._proxy._binding.send(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/gfuhr/projects/immediate-action-prototypes/onvif/.onvif/lib/python3.12/site-packages/zeep/wsdl/bindings/soap.py", line 135, in send
    return self.process_reply(client, operation_obj, response)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/gfuhr/projects/immediate-action-prototypes/onvif/.onvif/lib/python3.12/site-packages/zeep/wsdl/bindings/soap.py", line 229, in process_reply
    return self.process_error(doc, operation)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/gfuhr/projects/immediate-action-prototypes/onvif/.onvif/lib/python3.12/site-packages/zeep/wsdl/bindings/soap.py", line 391, in process_error
    raise Fault(
zeep.exceptions.Fault

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/gfuhr/projects/immediate-action-prototypes/onvif/onvif_listener.py", line 16, in <module>
    msgs = pullpoint.PullMessages(Timeout="PT5S", MessageLimit=1)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/gfuhr/projects/immediate-action-prototypes/onvif/.onvif/lib/python3.12/site-packages/onvif/utils/service.py", line 106, in wrapped_method
    result = attr(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "/home/gfuhr/projects/immediate-action-prototypes/onvif/.onvif/lib/python3.12/site-packages/onvif/services/events/pullpoint.py", line 22, in PullMessages
    return self.operator.call(
           ^^^^^^^^^^^^^^^^^^^
  File "/home/gfuhr/projects/immediate-action-prototypes/onvif/.onvif/lib/python3.12/site-packages/onvif/operator.py", line 210, in call
    raise ONVIFOperationException(operation=method, original_exception=e)
onvif.utils.exceptions.ONVIFOperationException: ONVIF operation 'PullMessages' failed: SOAP Error: code=SOAP-ENV:Sender, subcode=InvalidArgs

Here's my code:

from onvif import ONVIFClient

client = ONVIFClient("192.168.1.107", 80, "****", "****")
device = client.devicemgmt()      # Device Management (Core)
info = device.GetDeviceInformation()
print(info)

events = client.events()        # Events
subscription_ref = client.events().CreatePullPointSubscription()
print(subscription_ref)
pullpoint = client.pullpoint(subscription_ref)

print("Listening for events...")
msgs = pullpoint.PullMessages(Timeout="PT5S", MessageLimit=1)
print("Received messages:")
for msg in msgs.NotificationMessage:
    print(msg)

before crashind that will print:

{
    'Manufacturer': 'AXIS',
    'Model': 'P3268-LVE',
    'FirmwareVersion': '12.4.59',
    'SerialNumber': 'B8A44FA0DC7A',
    'HardwareId': '968.33'
}
{
    'SubscriptionReference': {
        'Address': {
            '_value_1': 'http://192.168.1.107/onvif/services',
            '_attr_1': None
        },
        'ReferenceParameters': {
            '_value_1': [
                <Element {http://www.axis.com/2009/event}SubscriptionId at 0x75400f610480>
            ],
            '_attr_1': None,
            'SubscriptionId': 8
        },
        'Metadata': None,
        '_value_1': None,
        '_attr_1': None
    },
    'CurrentTime': datetime.datetime(2026, 1, 21, 21, 8, 35, tzinfo=<isodate.tzinfo.Utc object at 0x75400ff30dd0>),
    'TerminationTime': datetime.datetime(2026, 1, 21, 21, 13, 35, tzinfo=<isodate.tzinfo.Utc object at 0x75400ff30dd0>),
    '_value_1': None
}
Listening for events...

same happened when using the pull_live_events.py sample.

[kaburagisec]

Thank you for your report, your bug is caused because the camera considers the parameter value you entered to be invalid/illegal, please note that each camera has a limit on the parameter value for Timeout or MessageLimit in the PullMessages operation in Event (PullPoint binding) service.

You can read it in the official documentation https://developer.onvif.org/pub/specs/branches/development/doc/Core.xml and look at section 9.1.2 Pull messages, it says about request parameters:

request:
    Timeout [xs:duration]
    Maximum time to block until this method returns.

    MessageLimit [xs:int]
    Upper limit for the number of messages to return at once. A server implementation may decide to return less messages.

Maybe you can increase the value of one of these parameters to find out the limitations of the camera you are using. Hope this information helps.

[kaburagisec]

If in the error you see SOAP Error: code=SOAP-ENV:Sender, subcode=InvalidArgs, it is also explained there that the error is in the sender with the error subcode being InvalidArgs. Errors that start with SOAP are error responses from the ONVIF camera itself.

[gustavofuhr]

I tried with different values and got the same error.

You're saying that there is a response from the camera but the SOAP xml is invalid, is that it?

Is there any way to debug what the camera is responding?

[kaburagisec]

You can add capture_xml to the client instance, then perform operations, and print last_sent_xml to see the sent xml and last_received_xml to see the received xml response like this:

from onvif import ONVIFClient

client = ONVIFClient(
    host='192.168.1.10',
    port=80,
    username='admin',
    password='password',
    capture_xml=True  # Enable XML capture
)

# Make ONVIF calls - XML will be logged
device_info = client.devicemgmt().GetDeviceInformation()

# Access captured XML
if client.xml_plugin:
    print("Last Request:", client.xml_plugin.last_sent_xml)
    print("Last Response:", client.xml_plugin.last_received_xml)

[kaburagisec]

For further information on this, see https://stackoverflow.com/questions/33260460/pullmessages-always-return-invalidargval. Since I don't have an Axis camera, I haven't tried debugging it further. What version of ONVIF is on the camera you're testing?