Django Redis

---

1. Caching Objects

from django.core.cache import cache

# Cache an object for 1 hour
cache.set("my_object", my_object, timeout=3600)

# Retrieve the cached object
my_object = cache.get("my_object")

2. Caching Querysets

from django.core.cache import cache
from django.db.models import QuerySet

# Cache a queryset for 1 hour
cache.set("my_queryset", my_queryset, timeout=3600)

# Retrieve the cached queryset
my_queryset = cache.get("my_queryset")

3. Caching Template Fragments

from django.core.cache import cache
from django.template import Template, Context

# Cache a template fragment for 1 hour
cache.set("my_fragment", Template("{{ my_variable }}").render(Context({"my_variable": "value"})), timeout=3600)

# Retrieve the cached template fragment
my_fragment = cache.get("my_fragment")

4. Caching Functions

from django.core.cache import cache

@cache.memoize()
def my_function(arg1, arg2):
    # Function body
    pass

5. Caching Class Methods

from django.core.cache import cache

class MyClass:
    @cache.memoize()
    def my_method(self, arg1, arg2):
        # Method body
        pass

6. Caching Static Methods

from django.core.cache import cache

class MyClass:
    @staticmethod
    @cache.memoize()
    def my_static_method(arg1, arg2):
        # Method body
        pass

7. Caching Property Getters

from django.core.cache import cache

class MyClass:
    @cache.memoize()
    @property
    def my_property(self):
        # Property body
        pass

8. Caching ListView

from django.core.cache import cache
from django.views.generic import ListView

class MyListView(ListView):
    cache_page = True
    timeout = 3600

9. Caching DetailView

from django.core.cache import cache
from django.views.generic import DetailView

class MyDetailView(DetailView):
    cache_page = True
    timeout = 3600

10. Caching with cache_control header

from django.core.cache import cache
from django.http import HttpResponse

# Cache a response for 1 hour and set cache-control header
response = HttpResponse("My response")
response["Cache-Control"] = "max-age=3600"
cache.set("my_response", response, timeout=3600)

11. Caching with etag

from django.core.cache import cache
from django.http import HttpResponse

# Cache a response with etag
response = HttpResponse("My response")
response["Etag"] = "my-etag"
cache.set("my_response", response, timeout=3600)

12. Caching with Vary header

from django.core.cache import cache
from django.http import HttpResponse

# Cache a response with Vary header
response = HttpResponse("My response")
response["Vary"] = "User-Agent"
cache.set("my_response", response, timeout=3600)

13. Caching with Multiple Keys

from django.core.cache import cache

# Cache an object with multiple keys
cache.set("my_object:key1", my_object, timeout=3600)
cache.set("my_object:key2", my_object, timeout=3600)

14. Caching with Versioning

from django.core.cache import cache

# Cache an object with versioning
cache.set("my_object:v1", my_object, timeout=3600)
cache.set("my_object:v2", my_object, timeout=3600)

15. Caching with Tags

from django.core.cache import cache

# Cache an object with tags
cache.set("my_object", my_object, timeout=3600, tags=["my_tag"])

16. Caching with Invalidation

from django.core.cache import cache

# Invalidate a cached object by key
cache.delete("my_object")

# Invalidate a cached object by tags
cache.delete_many(["my_tag"])

17. Using Redis as a Database

from django_redis import get_redis_connection

# Get a Redis connection
redis_connection = get_redis_connection("default")

# Set a key-value pair in Redis
redis_connection.set("my_key", "my_value")

# Retrieve a value from Redis
value = redis_connection.get("my_key")

18. Using Redis for Pub/Sub

from django_redis import get_redis_connection

# Get a Redis connection
redis_connection = get_redis_connection("default")

# Publish a message to a channel
redis_connection.publish("my_channel", "my_message")

# Subscribe to a channel and listen for messages
redis_connection.subscribe(["my_channel"])
for message in redis_connection.listen():
    print(message["channel"], message["data"])

19. Using Redis for Rate Limiting

from django_redis import get_redis_connection
from django.views.decorators import cache

@cache.rate_limiter(key="my_rate_limit", rate="1/s")
def my_view(request):
    # View code
    pass

20. Using Redis for Caching with Side Effects

from django_redis.serializers import json
from django_redis import get_redis_connection

# Set a value in Redis with a side effect
redis_connection = get_redis_connection("default")
redis_connection.execute_command("SET my_key my_value", side_effects=True)

# Retrieve a value from Redis with a side effect
value = redis_connection.execute_command("GET my_key", side_effects=True)

21. Using Redis for Geospatial Queries

from django_redis import get_redis_connection

# Get a Redis connection
redis_connection = get_redis_connection("default")

# Add a point to a geospatial index
redis_connection.geoadd("my_geospatial_index", 10, 20, "my_point")

# Perform a geospatial query
results = redis_connection.georadius("my_geospatial_index", 10, 20, 1000)

22. Using Redis for HyperLogLog

from django_redis import get_redis_connection

# Get a Redis connection
redis_connection = get_redis_connection("default")

# Add values to a HyperLogLog
redis_connection.pfadd("my_hyperloglog", "value1", "value2", "value3")

# Get the cardinality of a HyperLogLog
cardinality = redis_connection.pfcount("my_hyperloglog")

23. Using Redis for Time Series

from django_redis import get_redis_connection

# Get a Redis connection
redis_connection = get_redis_connection("default")

# Add a data point to a time series
redis_connection.ts.add("my_time_series", 1650729600, 10)

# Retrieve data points from a time series
results = redis_connection.ts.range("my_time_series", 1650729600, 1650733200)

24. Using Redis for Stream Processing

from django_redis import get_redis_connection

# Get a Redis connection
redis_connection = get_redis_connection("default")

# Create a stream
redis_connection.xadd("my_stream", {"key1": "value1", "key2": "value2"})

# Read messages from a stream
messages = redis_connection.xread({"my_stream": 0}, block=True)

25. Using Redis for Search with RediSearch

from django_redis import get_redis_connection

# Get a Redis connection
redis_connection = get_redis_connection("default")

# Add a document to a RediSearch index
redis_connection.ft_create("my_index", schema=[("name", "TEXT"), ("description", "TEXT")])
redis_connection.ft_add("my_index", "my_document", {"name": "My Document", "description": "This is my document."})

# Search in a RediSearch index
results = redis_connection.ft_search("my_index", "My Document")

26. Using Redis for Distributed Locks

from django_redis import get_redis_connection

# Get a Redis connection
redis_connection = get_redis_connection("default")

# Acquire a distributed lock
lock = redis_connection.lock("my_lock", timeout=10)
try:
    # Execute critical section
    pass
finally:
    # Release the lock
    lock.release()

27. Using Redis for Counter

from django_redis import get_redis_connection

# Get a Redis connection
redis_connection = get_redis_connection("default")

# Increment a counter
redis_connection.incr("my_counter")

# Get the value of a counter
value = redis_connection.get("my_counter")

28. Using Redis for Bitmap

from django_redis import get_redis_connection

# Get a Redis connection
redis_connection = get_redis_connection("default")

# Set a bit in a bitmap
redis_connection.setbit("my_bitmap", 10, 1)

# Get the value of a bit in a bitmap
value = redis_connection.getbit("my_bitmap", 10)

29. Using Redis for Bloom Filter

from django_redis import get_redis_connection

# Get a Redis connection
redis_connection = get_redis_connection("default")

# Add an element to a Bloom filter
redis_connection.bf.add("my_bloom_filter", "my_element")

# Check if an element exists in a Bloom filter
exists = redis_connection.bf.exists("my_bloom_filter", "my_element")

30. Using Redis for Session Storage

from django.contrib.sessions.backends.db import SessionStore

class RedisSessionStore(SessionStore):
    def __init__(self, session_key=None):
        super().__init__(session_key)
        self.redis_connection = get_redis_connection("default")

    def load(self):
        session_data = self.redis_connection.get(self.session_key)
        if session_data:
            self.session_data = json.loads(session_data)

    def save(self):
        self.redis_connection.set(self.session_key, json.dumps(self.session_data))

31. Using Redis for Rate Limiting with Django REST Framework

from django_redis import get_redis_connection
from rest_framework.views import APIView

class RateLimitedAPIView(APIView):
    redis_connection = get_redis_connection("default")

    def dispatch(self, request, *args, **kwargs):
        ip_address = request.META.get("REMOTE_ADDR")
        key = f"rate_limit:{ip_address}"
        if self.redis_connection.incr(key) > 10:
            return Response({"error": "Too many requests"}, status=429)
        return super().dispatch(request, *args, **kwargs)

32. Using Redis for Caching with Django Signals

from django.db.models.signals import post_save
from django.dispatch import receiver
from django_redis import get_redis_connection

@receiver(post_save, sender=MyModel)
def invalidate_cache_on_post_save(sender, **kwargs):
    redis_connection = get_redis_connection("default")
    redis_connection.invalidate_patterns(["my_cached_pattern*"])

33. Using Redis for Notifications

from channels.layers import get_channel_layer
from django_redis import get_redis_connection

def send_notification(user_id, notification):
    channel_layer = get_channel_layer()
    redis_connection = get_redis_connection("default")
    redis_connection.publish(f"notifications:{user_id}", json.dumps(notification))
    channel_layer.group_send(f"notifications:{user_id}", {"type": "notify", "data": notification})

34. Using Redis for WebSockets with Channels

from channels.routing import ProtocolTypeRouter, URLRouter
from channels.auth import AuthMiddlewareStack
from django.urls import path

application = ProtocolTypeRouter({
    "websocket": AuthMiddlewareStack(
        URLRouter(
            [
                path("notifications/", "my_app.consumers.NotificationConsumer"),
            ]
        )
    ),
})

35. Using Redis for Background Tasks with Celery

from celery import Celery

app = Celery("my_app")
app.conf.broker_url = "redis://localhost:6379"
app.conf.result_backend = "redis://localhost:6379"

36. Using Redis for Queuing with RQ

from rq import Queue
from redis import StrictRedis

redis_connection = StrictRedis()
queue = Queue(name="my_queue", connection=redis_connection)
queue.enqueue("my_task", args=("some", "arguments"))