why KeyError when Get doesn't find a key?

[Michael Wang-Helmke]

Hi,

I'm bugged that the semantics for the Get function are to "fail" with an exception if Get doesn't find a key.  I strongly feel exceptions should be for legitimate failures and errors.  I don't see a missing key being an error condition.  A common use case for me is to test if a key is present by trying to Get it.

I would much prefer that Get return None when there is no key present.  I have modified my local copy to have this behavior.

Does anyone see any issues with this?

Thank you,

Michael

[Árni Már Jónsson]

Hi,

I don´t really remember why I chose those semantics, but I imagine it was to mimic the semantics of the builtin Python type dict.

Changing the semantics this late in the game is not an option I think, but I´d be very happy to add a "default" keyword argument, which is returned when Get() doesn´t find its value. 

Perhaps there´s a simpler backwards-compatible way to achieve the same thing?

Regards, Árni Már

[Michael Wang-Helmke]

Hi,

The default argument is a good idea.  I would just pass in "None" as a default.  In the mean time, I modified my version of the source and it works nicely for me.  Thank you for writing the python bindings for this, it has been very helpful.

Thank you,

Michael

[Árni Már Jónsson]

I seem to already have implemented exactly this. Works for both DB objects and Snapshots.

>>> db = leveldb.LevelDB('.')

>>> db.Get('hello')

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

KeyError

>>> db.Get('hello', default = 'yes')

'yes'

>>>

have fun,

Árni Már