【英文】Django项目中连接Redis

Posted on Edited on In Views:

Preface

Learn notes on Redis connection in Django projects

Download dependencies

1
2
pip3 install redis
pip3 install django-redis

Modify global configuration

  • Add CACHES configuration after DATABASES configuration in the global configuration

CLIENT_CLASS: specify the client
CONNECTION_POOL_KWARGS: specify the connection pool configuration

max_connections: specify the maximum number of connections

PASSWORD: specify the password, leave it blank if there is none

//settings.py
1
2
3
4
5
6
7
8
9
10
11
CACHES = {
    'default': {
        'BACKEND': 'django_redis.cache.RedisCache',
        'LOCATION': 'redis://127.0.0.1:6379',
        'OPTIONS': {
            'CLIENT_CLASS': 'django_redis.client.DefaultClient',
            'CONNECTION_POOL_KWARGS': {'max_connections': 200},
            #'PASSWORD': ''
        }
    }
}

Redis decorator as MySQL cache

  • When querying data from MySQL, first query from Redis
    • If the data is available in Redis, retrieve it directly from Redis
    • If the data is not available in Redis, query it from MySQL and store it in Redis
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
import json
from functools import wraps
from django_redis import get_redis_connection
from django.db import models

# Define a cache decorator
_cache = get_redis_connection('default')
def cache(func):
    @wraps(func)
    def wrapper(obj, *args):
        key = args[0]
        value = _cache.get(key)
        if value:
            return json.loads(value)
        result = func(obj, *args)
        _cache.set(key, json.dumps(result))
        return result
    return wrapper

class User(models.Model):
    id = models.IntegerField(primary_key=True)
    name = models.CharField(max_length=5)

    # Define a class method `get()` using the cache decorator. When data needs to be retrieved from the cache, simply call `get()` method
    @classmethod
    @cache
    def get(cls, id):
        # Query data from MySQL and save it to Redis
        result = cls.objects.get(id=id)
        return {
            'id': result.id,
            'name': result.name
            # If there is a date-time type data, it needs to be converted to string
            #'time': str(result.time)
        }

CRUD operations

Import modules

1
from django_redis import get_redis_connection

Get connection

1
cache = get_redis_connection('default')

Add or modify

Without specifying expiration time

1
cache.set('<key>', '<value>')

Specify expiration time

<num>: specify the expiration time in seconds

1
cache.set('<key>', '<value>', <num>)

Done

References

Bilibili - Turing Academy Tutorial