nonatofabio / redis-py

Redis Python Client

redis-py

The Python interface to the Redis key-value store.

Installation | Usage | Advanced Topics | Contributing

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Python Notice

redis-py 4.3.x will be the last generation of redis-py to support python 3.6 as it has been End of Life'd. Async support was introduced in redis-py 4.2.x thanks to aioredis, which necessitates this change. We will continue to maintain 3.6 support as long as possible - but the plan is for redis-py version 4.4+ to officially remove 3.6.

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Installation

Start a redis via docker:

docker run -p 6379:6379 -it redis/redis-stack:latest

To install redis-py, simply:

$ pip install redis

For faster performance, install redis with hiredis support, this provides a compiled response parser, and for most cases requires zero code changes. By default, if hiredis >= 1.0 is available, redis-py will attempt to use it for response parsing.

$ pip install redis[hiredis]

Looking for a high-level library to handle object mapping? See redis-om-python!

Usage

Basic Example

>>> import redis
>>> r = redis.Redis(host='localhost', port=6379, db=0)
>>> r.set('foo', 'bar')
True
>>> r.get('foo')
b'bar'

The above code connects to localhost on port 6379, sets a value in Redis, and retrieves it. All responses are returned as bytes in Python, to receive decoded strings, set decode_responses=True. For this, and more connection options, see these examples.

Connection Pools

By default, redis-py uses a connection pool to manage connections. Each instance of a Redis class receives its own connection pool. You can however define your own redis.ConnectionPool.

>>> pool = redis.ConnectionPool(host='localhost', port=6379, db=0)
>>> r = redis.Redis(connection_pool=pool)

Alternatively, you might want to look at Async connections, or Cluster connections, or even Async Cluster connections.

Redis Commands

There is built-in support for all of the out-of-the-box Redis commands. They are exposed using the raw Redis command names (HSET, HGETALL, etc.) except where a word (i.e. del) is reserved by the language. The complete set of commands can be found here, or the documentation.

Advanced Topics

The official Redis command documentation does a great job of explaining each command in detail. redis-py attempts to adhere to the official command syntax. There are a few exceptions:

• MULTI/EXEC: These are implemented as part of the Pipeline class. The pipeline is wrapped with the MULTI and EXEC statements by default when it is executed, which can be disabled by specifying transaction=False. See more about Pipelines below.

• SUBSCRIBE/LISTEN: Similar to pipelines, PubSub is implemented as a separate class as it places the underlying connection in a state where it can't execute non-pubsub commands. Calling the pubsub method from the Redis client will return a PubSub instance where you can subscribe to channels and listen for messages. You can only call PUBLISH from the Redis client (see this comment on issue #151 for details).

For more details, please see the documentation on advanced topics page.

Pipelines

The following is a basic example of a Redis pipeline, a method to optimize round-trip calls, by batching Redis commands, and receiving their results as a list.

>>> pipe = r.pipeline()
>>> pipe.set('foo', 5)
>>> pipe.set('bar', 18.5)
>>> pipe.set('blee', "hello world!")
>>> pipe.execute()
[True, True, True]

PubSub

The following example shows how to utilize Redis Pub/Sub to subscribe to specific channels.

>>> r = redis.Redis(...)
>>> p = r.pubsub()
>>> p.subscribe('my-first-channel', 'my-second-channel', ...)
>>> p.get_message()
{'pattern': None, 'type': 'subscribe', 'channel': b'my-second-channel', 'data': 1}

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Author

redis-py is developed and maintained by Redis Inc. It can be found here, or downloaded from pypi.

Special thanks to:

• Andy McCurdy ([email protected]) the original author of redis-py.
• Ludovico Magnocavallo, author of the original Python Redis client, from which some of the socket code is still used.
• Alexander Solovyov for ideas on the generic response callback system.
• Paul Hubbard for initial packaging support.