Flask-And-Redis

Flask-And-Redis provides simple as dead support of Redis database for Flask applications. Extension built around beautiful redis-py library by Andy McCurdy.

Note

Flask-And-Redis named as is, cause Flask-Redis name already taken, but that library didn’t match my needs.

Installation

Use pip to install Flask-And-Redis to your system or virtual environment:

$ pip install Flask-And-Redis

Otherwise you could download source dist from GitHub or PyPI and put flask_redis.py file somewhere to $PYTHONPATH, but this way is not recommended. Use pip for all good things.

Usage

In regular case all you need is importing Redis instance and initialize it with app instance, like:

from flask import Flask
from flask_redis import Redis

app = Flask(__name__)
redis = Redis(app)

But if you use application factories you could use init_app() method,

redis = Redis()
# The later on
app = create_app('config.cfg')
redis.init_app(app)

Also later you can get redis connection from app.extensions['redis'] dict, where key is config prefix and value is configured redis connection.

Configuration

Flask-And-Redis understands all keyword arguments which should be passed to redis.StrictRedis or redis.Redis classes init method. In easiest way all you need is putting

  • REDIS_HOST
  • REDIS_PORT
  • REDIS_DB

to your settings module. Other available settings are:

  • REDIS_PASSWORD
  • REDIS_SOCKET_TIMEOUT
  • REDIS_CONNECTION_POOL
  • REDIS_CHARSET
  • REDIS_ERRORS
  • REDIS_DECODE_RESPONSES
  • REDIS_UNIX_SOCKET_PATH

Later these values would initialize redis connection and all public methods of connection’s instance would be copied to Redis. Also connection would be stored in Redis.connection attribute and app.extensions['redis'] dict.

In addition extension has two more configuration options and ability to connect to multiple redis databases.

REDIS_CLASS

New in version 0.5.

Before 0.5 version only redis.Redis connection used. But as times change and redis.StrictRedis class grab default status we start to using it as our default connection class.

To change this behavior or even use your own class for redis connection you should pass a class itself or its path to REDIS_CLASS setting as:

from redis import Redis
REDIS_CLASS = Redis

or:

REDIS_CLASS = 'redis.Redis'
REDIS_CLASS = 'path.to.module.Redis'

REDIS_URL

New in version 0.2.

Sometimes, your redis settings stored as redis://... url (like in Heroku or DotCloud services), so you could to provide just REDIS_URL setting and Flask-And-Redis auto parsed that value and will configure then valid redis connection.

In case, when REDIS_URL provided all appropriate configurations, and other keys are overwritten using their values at the present URI.

Config prefix

New in version 0.4.

Config prefix allows you to determine the set of configuration variables used to configure redis.Redis connection. By default, config prefix REDIS would be used.

But when you want to initialize multiple redis connections, you could do this like:

from flask import flask
from flask.ext.redis import Redis

app = Flask(__app__)
app.config['REDIS_HOST'] = 'localhost'
app.config['REDIS_PORT'] = 6379
app.config['REDIS_DB'] = 0
redis1 = Redis(app)

app.config['REDIS2_URL'] = 'redis://localhost:6379/1'
redis2 = Redis(app, 'REDIS2')

API

class flask_redis.Redis(app=None, config_prefix=None)

Simple as dead support of Redis database for Flask apps.

__init__(app=None, config_prefix=None)

Initialize Redis extension for Flask application.

If app argument provided then initialize redis connection using application config values.

If no app argument provided you should do initialization later with init_app() method.

Generally extension expects configuration to be prefixed with REDIS config prefix, to customize things pass different config_prefix here or on calling init_app() method. For example, if you have URL to Redis in CACHE_URL config key, you should pass config_prefix='CACHE' to extension.

Parameters:
  • app – flask.Flask application instance.
  • config_prefix – Config prefix to use. By default: REDIS
connection

Return Redis connection for current app.

get_app()

Get current app from Flast stack to use.

This will allow to ensure which Redis connection to be used when accessing Redis connection public methods via plugin.

init_app(app, config_prefix=None)

Actual method to read redis settings from app configuration, initialize Redis connection and copy all public connection methods to current instance.

Parameters:
  • app – flask.Flask application instance.
  • config_prefix – Config prefix to use. By default: REDIS

Changelog

1.0 (2019-02-14)

  • Drop Python 2.6 & 3.3 support, ensure Python 3.6+ support. Kudos to jezdez for pull request & implementation
  • Use inspect.getfullargspec() if available. Kudos to vibiu for pull request & implementation

0.7 (2016-11-12)

  • Improve multiple app support. Kudos to timothyqiu for pull request & implementation
  • Simplify running tests for test application

0.6 (2015-01-08)

  • Python 3 support.
  • Move documentation to Read the Docs.
  • Refactor example test project to Comments app which shows how to use two Redis databases simultaneously.

0.5 (2013-05-10)

  • Use redis.StrictRedis as connection class by default.
  • Understands unix socket path in REDIS_HOST.
  • Updates to README.

0.4 (2012-09-29)

  • Big refactor for Redis class. Do not inherit redis.Redis class, store active redis connection in Redis.connection attribute and app.extensions['redis'] dict.
  • Add support of config_prefix keyword argument for Redis or init_app() methods.
  • Support multiple redis connections in test application.

0.3.3 (2012-08-29)

  • Fix problem while parsing REDIS_URL value, strip unnecessary slashes from database path (like redis://localhost:6379/12/).

0.3.2 (2012-08-15)

  • Added redis as install requirement in setup.py.

0.3.1 (2012-06-19)

  • Move from flask_redis package to python module.
  • Little improvements for storing _flask_app attribute to Redis instance.

0.3 (2012-05-21)

0.2.1 (2012-03-30)

  • Convert REDIS_PORT to an int instance.

0.2 (2012-03-30)

  • Added support of REDIS_URL setting. By default, Redis will try to guess host, port, user, password and db settings from that value.

0.1 (2012-03-12)

  • Initial release.