Storing a custom Python object in Redis

Question

I'm trying to store a custom, serializable python object in Redis, but have encountered some strange behavior. The set method seems to function, but the get method only returns the value of the object's __repr__ method. For instance...

import redis

# initialize the redis connection pool
rs = redis.Redis(host='localhost', port=6379)

# define a custom class
class SomeCustomObject(object):
    pass

When I try to set the SomeCustomObject as a value, it appears to work:

>>> rs.set('c', SomeCustomObject())
True

However, when I get the value back, it's just the __repr__ string:

>>> rs.get('c')
'<__main__.SomeCustomObject object at 0x102496710>'

How do I store/get the instance back? I've not had much luck finding any info on this in the documentation, but surely I'm not the first one to encounter this?

Where are you serializing the object? – Itamar Haber Apr 07 '17 at 17:08 — Itamar Haber, Apr 07 '17 at 17:08

score 19 · Accepted Answer · edited May 23 '17 at 12:02

19

Use Pickle

Using the pickle module you can serialize and deserialize Python objects and pass them to Redis.

From this so answer - https://stackoverflow.com/a/20400288/4403600, it would look like this:

import pickle
import redis

# define a custom class
class SomeCustomObject(object):
    pass

# initialize the redis connection pool
rs = redis.Redis(host='localhost', port=6379)

# pickle and set in redis
rs.set('c', pickle.dumps(SomeCustomObject()))

# get from redis and unpickle
unpacked_object = pickle.loads(rs.get('c'))

Further reading - https://docs.python.org/2/library/pickle.html

edited May 23 '17 at 12:02

Community

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answered Apr 07 '17 at 17:08

Phillip Martin

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Ah, this is great. I was (for whatever misguided reason) under the impression redis-py would handle the pickling, so long as I had the `__getstate__`, `__setstate__` pieces handled. Thank you! – TayTay Apr 07 '17 at 17:12

Storing a custom Python object in Redis

1 Answers1