How do I use a MD5 hash (or other binary data) as a key name?

Question

I've been trying to use a MD5 hash as a key name on AppEngine, but the code I wrote raises a UnicodeDecodeError

from google.appengine.ext import db
import hashlib
key = db.Key.from_path('Post', hashlib.md5('thecakeisalie').digest())

I don't want to use hexdigest() as that is not only a kludge, but an inferior one too (base64 would do a better job).

Answer 1

The App Engine Python docs says:

A key_name is stored as a Unicode string (with str values converted as ASCII text).

The key has to be an unicode-encodeable-string. You need to change the digest() call to hexdigest(), ie:

k = hashlib.md5('thecakeisalie').hexdigest()