CloudEvents/EG Events must recognize magic events

[rakshith91]

Fixes #19247

[annatisch]

Is it possible an IndexError could be raised here?

[annatisch]

And in what case would it raise a KeyError?
Do we also need different handling for a StopIteration error? In that scenario, it meant that we had been passed the right object, but the payload was not valid - so I would expect that to then raise a ValueError, no?

[rakshith91]

Is it possible an IndexError could be raised here?

I cannot think of a scenario which could raise IndexError, and in case it is, we still return the object as is - and i have tried sending events to EH in diffferent formats - it always returns a "list"

And in what case would it raise a KeyError?

A keyerror is raised when we try to subscript a SB message with 0. essentially, service bus message is a dict. which is fetched by json.loads(next(obj.body)). So doing a json.loads(next(obj.body))[0] will give you a key error.

[rakshith91]

Do we also need different handling for a StopIteration error
No - uamqp does't throw stop iteration https://github.com/Azure/azure-uamqp-python/blob/master/uamqp/message.py#L1159-L1162

[annatisch]

Interesting - so if the Event body is an empty list - calling next on it doesn't raise? What does it do?

[rakshith91]

m = message.Message(body= b'', body_type=uamqp.MessageBodyType.Data)
for data in m.get_data():
  print(data)

>>> b''

[rakshith91]

/check-enforcer override