Redis-py¶

install redis-py¶

redis-py client for Redis

pip install redis[hiredis]
mamba install redis-py hiredis

methods¶

time can be represented by int or a Python timedelta/datetime object

• r.setx(key, time, value) set value of key that expires in time seconds

• r.expire(key, time) set expire flag for time seconds

• r.psetex(key, time_ms, value) set value of key that expires in time_ms milliseconds

• r.expireat(key, when) set an expire flag

• r.persist(key) remove expiration

• r.ttl(key) return the number of seconds until the key expires

• r.pttl(key) return the number of milliseconds until the key expires

create server¶

import redis
r = redis.Redis(host='localhost', port=6379, db=0)
print(r.ping())
print(r.keys("*"))

connetect to local/cluster¶

from redis.cluster import RedisCluster

# `decode_responses=True` convert return value from bytes to str.
#r = redis.Redis(host='localhost', port=6379, decode_responses=True)
rc = RedisCluster(host='localhost', port=16379)

print(rc.get_nodes())
# [[host=127.0.0.1,port=16379,name=127.0.0.1:16379,server_type=primary,
#  redis_connection=Redis<ConnectionPool<Connection<host=127.0.0.1,port=16379,db=0>>>], ...

connect with tls¶

import redis

r = redis.Redis(
    host="my-redis.cloud.redislabs.com",
    port=6379,
    username="default", # use your Redis user. More info https://redis.io/docs/management/security/acl/
    password="secret", # use your Redis password
    ssl=True,
    ssl_certfile="./redis_user.crt",
    ssl_keyfile="./redis_user_private.key",
    ssl_ca_certs="./redis_ca.pem",
)

examples¶

r.set('key', 'val')
r.get('key')

dv = {
    'a': 'x',
    'b': 'y'
}
r.mset(dv)
r.get('b')

lv = ['a', 'b']
r.sadd('lv', *lv)
r.smembers('lv')

lv = ['x', 'y']
r.lpush('lp', *lv)
r.lrange('lp', 0, -1)

import json
jv = {
    'name': 'John',
    'age': 20,
    'address':{
        'number': 19,
        'street': 'Goldey',
        'suburb': 'Cuddly'
    },
    'skills': ['art', 'math']
}
r.set('jv', json.dumps(jv))
json.loads(r.get('jv'))

difference between redis.Redis and redis.StrictRedis¶

In the redis-py library, both redis.Redis and redis.StrictRedis are classes that provide a client interface for interacting with a Redis server. However, there is a subtle historical difference between them.

1. redis.Redis (Deprecated):
2. redis.Redis was the original class in redis-py for creating a Redis client.
3. Over time, the developers realized that the name StrictRedis better reflects the fact that the library adheres strictly to the official Redis command syntax.

4. To avoid confusion, StrictRedis was introduced, and it was recommended to use StrictRedis instead of Redis. As a result, Redis is now deprecated.

5. redis.StrictRedis (Recommended):

6. redis.StrictRedis is the replacement for redis.Redis and is the recommended class to use in modern code.
7. It provides a clean and consistent API, strictly following the official Redis command syntax.
8. StrictRedis is more feature-complete, and its usage is considered best practice.

Usage:

# Recommended: Use StrictRedis
import redis
redis_client = redis.StrictRedis(host='localhost', port=6379, db=0, decode_responses=True)

# Deprecated: Avoid using Redis
# import redis
# redis_client = redis.Redis(host='localhost', port=6379, db=0, decode_responses=True)

In summary, while both redis.Redis and redis.StrictRedis can be used, it's strongly recommended to use redis.StrictRedis in modern code to take advantage of the latest features, improvements, and best practices. If you encounter existing code that uses redis.Redis, consider updating it to use redis.StrictRedis.