how to store a complex object in redis (using redis-py)

Question

The hmset function can set the value of each field, but I found that if the value itself is a complex structured object, the value return from hget is a serialized string, not the original object

e.g

images= [{'type':'big', 'url':'....'},      {'type':'big', 'url':'....'},      {'type':'big', 'url':'....'}]     redis = Redis() redis.hset('photo:1', 'images', images)  i = redis.hget('photo:1', 'images') print type(i) 

the type of i is a string, not a python object, is there any way to solve this problem besides manually parse each fields?

Answer 1

Actually, you can store python objects in redis using the built-in module pickle.

Here is example.

import pickle import redis  r = redis.StrictRedis(host='localhost', port=6379, db=0) obj = ExampleObject() pickled_object = pickle.dumps(obj) r.set('some_key', pickled_object) unpacked_object = pickle.loads(r.get('some_key')) obj == unpacked_object 

Answer 2

If your data is JSON-serializable, then that may be the better option than saving python pickles to an external database, since it's a more common standard outside of Python, is more human-readable on its own, and avoids a rather large attack vector.

JSON Example:

import json import redis  r = redis.StrictRedis(host='localhost', port=6379, db=0)  images= [     {'type':'big', 'url':'....'},     {'type':'big', 'url':'....'},     {'type':'big', 'url':'....'}, ]  # Convert python dict to JSON str and save to Redis json_images = json.dumps(images) r.set('images', json_images)  # Read saved JSON str from Redis and unpack into python dict unpacked_images = json.loads(r.get('images')) images == unpacked_images 

python 3:

unpacked_images = json.loads(r.get('images').decode('utf-8')) images == unpacked_images