UnicodeDecodeError on value conversion about snimpy HOT 7 CLOSED

The MIB says that cdpCacheDevicePort is a DisplayString. Such a type mandates the use of ASCII charset, hence the error. The difference you get is a bug and you should get the same exception during your first try.

With the not-yet-released latest version of Snimpy, thanks to @Daemonae, it is possible to fix the type with something like this:

m.cdpCacheDevicePort.proxy.typeName = 'somethingelse'

You'll have to find what somethingelse could be. Unfortunately, it is not possible to use OCTET STRING here. SNMPv2-TC defines TAddress which is quite like an OCTET STRING.

The other way around is to fix the MIB as the type is not a DisplayString. Change the SYNTAX to OCTET STRING to fix this "problem". I have just pushed 0.8.4 with those changes so that you can test this workaround.

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Hi,

Thanks for such a quick answer!

I've tried out the potential fixes - editing the MIB and changing DisplayString to OCTET STRING works as expected.

However, setting:

m.cdpCacheDevicePort.proxy.typeName = 'TAddress'

Still returns the same error. Is this related to the 'base type' still being DisplayString?

One other question - would you consider adding a way to return the 'raw' value with no coercion/casting? I know this is the wrong place to fix the problem, but given that vendors often play 'fast and loose' and don't obey the standards/match the MIBs, it could potentially be useful, even just for debugging these kinds of situations?

Many thanks once again for a quick and detailed response!

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Yes, the base type is still the one of display strings (ie types with a format), so the workaround won't work.

As for disabling type coercion, yes, we can try to do that when outputting values. This could be done in a context or in a special session (RawSession for example).

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The session stuff is the wrong abstraction. Let me think a bit. This could also be just a parameter for the manager.

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That would work - I was mostly thinking of cases where you might want to try getting the coerced value, and if that failed, get the raw value - not sure how that could be implemented:

try:
    # Get the coerced/converted value as normal
    x = m.Foo[id]
except UnicodeDecodeError:
    # Something went wrong with conversion - get the raw value
    x = ???

I could imagine doing something like:

```python
m.getRaw(True)
x = m.Foo[id]
m.getRaw(False)

Or maybe a raw method on the manager?

m.raw.Foo[id]

Just some quick thinking around the idea, so take it all with a pinch of salt :-)

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👍 many thanks!

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With the latest commit, you can pass loose=True when creating a manager.

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