### Install django-cacheops

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Installs the django-cacheops package using pip, either from PyPI or directly from its GitHub repository.

```bash
$
pip install django-cacheops

# Or from github directly
$ pip install git+https://github.com/Suor/django-cacheops.git@master
```

--------------------------------

### File Cache Primitives

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Shows the basic set, get, and delete operations for the file cache.

```python
from cacheops import file_cache

file_cache.set(cache_key, data, timeout=None)
file_cache.get(cache_key)
file_cache.delete(cache_key)
```

--------------------------------

### Cache Get/Set Primitives

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Demonstrates the basic cache primitives for setting, getting, and deleting data from the cache.

```python
from cacheops import cache

cache.set(cache_key, data, timeout=None)
cache.get(cache_key)
cache.delete(cache_key)
```

--------------------------------

### Dynamic Cacheops Prefix Based on Query Reflection

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Provides an example of a dynamic cacheops prefix function that inspects the query object to determine the prefix. This allows for context-aware caching based on databases queried and tables involved.

```python
def cacheops_prefix(query):
    query.dbs    # A list of databases queried
    query.tables # A list of tables query is invalidated on

    if set(query.tables) <= HELPER_TABLES:
        return 'helper:'
    if query.tables == ['blog_post']:
        return 'blog:'
```

--------------------------------

### Create Custom Django Template Tag with Cacheops

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Provides an example of creating a custom Django template tag using cacheops' `decorator_tag`. This allows for complex caching logic, such as conditional caching for staff users or varying cache keys based on context and language.

```python
from cacheops import cached_as, CacheopsLibrary

register = CacheopsLibrary()

@register.decorator_tag(takes_context=True)
def cache_menu(context, menu_name):
    from django.utils import translation
    from myapp.models import Flag, MenuItem

    request = context.get('request')
    if request and request.user.is_staff():
        # Use noop decorator to bypass caching for staff
        return lambda func: func

    return cached_as(
        # Invalidate cache if any menu item or a flag for menu changes
        MenuItem,
        Flag.objects.filter(name='menu'),
        # Vary for menu name and language, also stamp it as "menu" to be safe
        extra=("menu", menu_name, translation.get_language()),
        timeout=24 * 60 * 60
    )
```

--------------------------------

### Granular Cache Invalidation with Smaller Queries

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Illustrates how splitting database queries can lead to more granular cache invalidation. The first example shows a single query that invalidates on broader changes, while the second uses two queries for more precise invalidation based on specific events.

```python
Post.objects.filter(category__slug="foo")
# A single database query, but will be invalidated not only on
# any Category with .slug == "foo" change, but also for any Post change
```

```python
Post.objects.filter(category=Category.objects.get(slug="foo"))
# Two queries, each invalidates only on a granular event:
# either category.slug == "foo" or Post with .category_id == <whatever is there>
```

--------------------------------

### Define Caching Rules in Django Cacheops

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Configures automatic caching rules for Django models using the CACHEOPS setting. It specifies operations ('get', 'fetch', 'all'), timeouts, and model patterns. It also demonstrates how to disable caching for specific models.

```python
CACHEOPS = {
    # Automatically cache any User.objects.get() calls for 15 minutes
    # This also includes .first() and .last() calls,
    # as well as request.user or post.author access,
    # where Post.author is a foreign key to auth.User
    'auth.user': {'ops': 'get', 'timeout': 60*15},

    # Automatically cache all gets and queryset fetches
    # to other django.contrib.auth models for an hour
    'auth.*': {'ops': {'fetch', 'get'}, 'timeout': 60*60},

    # Cache all queries to Permission
    # 'all' is an alias for {'get', 'fetch', 'count', 'aggregate', 'exists'}
    'auth.permission': {'ops': 'all', 'timeout': 60*60},

    # Enable manual caching on all other models with default timeout of an hour
    # Use Post.objects.cache().get(...) 
    #  or Tags.objects.filter(...).order_by(...).cache()
    # to cache particular ORM request.
    # Invalidation is still automatic
    '*.*': {'ops': (), 'timeout': 60*60},

    # And since ops is empty by default you can rewrite last line as:
    '*.*': {'timeout': 60*60},

    # NOTE: binding signals has its overhead, like preventing fast mass deletes,
    #       you might want to only register whatever you cache and dependencies.

    # Finally you can explicitely forbid even manual caching with:
    'some_app.*': None,
}
```

--------------------------------

### Cache Specific Queryset Operations

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Cache only specific operations (e.g., 'count') for a queryset using the .cache() method with the 'ops' argument. This example caches the count operation but not the subsequent fetching of articles.

```python
qs = Article.objects.filter(tag=2).cache(ops=['count'])
# ... later usage ...
```

--------------------------------

### Call Cacheops Reap Conjunctions from Code

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Programmatically calls the cacheops.reap_conjs function, for example, from a Celery task, with specified chunk size and minimum conjunction set size.

```python
from cacheops import reap_conjs

@app.task
def reap_conjs_task():
    reap_conjs(
        chunk_size=2000,
        min_conj_set_size=100,
    )
```

--------------------------------

### Configure Redis Connection for Django Cacheops

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Sets up the Redis connection parameters for django-cacheops in Django's settings. It shows configurations using host/port, a Redis URL, a Unix socket path, and Sentinel for high availability. It also covers specifying a custom Redis client class.

```python
CACHEOPS_REDIS = {
    'host': 'localhost', # redis-server is on same machine
    'port': 6379,        # default redis port
    'db': 1,             # SELECT non-default redis database
                         # using separate redis db or redis instance
                         # is highly recommended

    'socket_timeout': 3,   # connection timeout in seconds, optional
    'password': '...',     # optional
    'unix_socket_path': '' # replaces host and port
}

# Alternatively the redis connection can be defined using a URL:
CACHEOPS_REDIS = "redis://localhost:6379/1"
# or
CACHEOPS_REDIS = "unix://path/to/socket?db=1"
# or with password (note a colon)
CACHEOPS_REDIS = "redis://:password@localhost:6379/1"

# If you want to use sentinel, specify this variable
CACHEOPS_SENTINEL = {
    'locations': [('localhost', 26379)], # sentinel locations, required
    'service_name': 'mymaster',          # sentinel service name, required
    'socket_timeout': 0.1,               # connection timeout in seconds, optional
    'db': 0                              # redis database, default: 0
    ...                                  # everything else is passed to Sentinel()
}

# Use your own redis client class, should be compatible or subclass redis.Redis
CACHEOPS_CLIENT_CLASS = 'your.redis.ClientClass'
```

--------------------------------

### Optimize Queryset Cloning with inplace()

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Demonstrates how to use the `.inplace()` method to make querysets mutating, thereby preventing unnecessary cloning and improving performance. The `.cloning()` method can be used to revert to the default cloning behavior. This is a micro-optimization for critical code paths.

```python
items = Item.objects.inplace().filter(category=12).order_by('-date')[:20]
```

--------------------------------

### Share Redis Instance with Cacheops Prefix

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Shows how to share a Redis instance among different applications or cache scopes by defining a prefix for cache keys. This can be done using a string or a callable that generates the prefix dynamically.

```python
CACHEOPS_PREFIX = lambda query: ...
# or
CACHEOPS_PREFIX = 'some.module.cacheops_prefix'
```

--------------------------------

### Configure Cacheops for Multiple Databases

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Explains how to configure cacheops to be database-agnostic or database-specific. The `db_agnostic` option in the `CACHEOPS` setting controls whether cache keys are generated independently of the database queried.

```python
CACHEOPS = {
    'some.model': {'ops': 'get', 'db_agnostic': False, 'timeout': ...}
}
```

--------------------------------

### Jinja2 Cached Tag Usage

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Illustrates the usage of cacheops' Jinja2 extension for template fragment caching. It shows the syntax for `cached_as` and `cached` tags with optional timeout and extra key parameters.

```jinja
{% cached_as <queryset> [, timeout=<timeout>] [, extra=<key addition>] %}
    ... some template code ...
{% endcached_as %}

or

{% cached [timeout=<timeout>] [, extra=<key addition>] %}
    ...
{% endcached %}
```

--------------------------------

### Advanced Caching Options in Django Cacheops

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Explains advanced caching configurations in django-cacheops, including `local_get` for in-process memory caching and `cache_on_save` for caching instances upon saving, which can be triggered by primary key or a specific field.

```python
``local_get: True``
    To cache simple gets for this model in process local memory.
    This is very fast, but is not invalidated in any way until process is restarted.
    Still could be useful for extremely rarely changed things.

``cache_on_save=True | 'field_name'``
    To write an instance to cache upon save. 
    Cached instance will be retrieved on ``.get(field_name=...)`` request.
    Setting to ``True`` causes caching by primary key.
```

--------------------------------

### Handling Cache Miss

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Shows how to handle a `CacheMiss` exception when trying to retrieve data that is not present in the cache.

```python
from cacheops import cache, CacheMiss

try:
    result = cache.get(key)
except CacheMiss:
    ... # deal with it
```

--------------------------------

### Redis Configuration for Insideout Mode

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Configures Redis 'maxmemory' and 'maxmemory-policy' for cacheops 'insideout' mode. Using 'allkeys-*' policies may lead to stale cache.

```bash
maxmemory 4gb
maxmemory-policy volatile-lru  # or other volatile-*

```

--------------------------------

### Clean File Cache Command

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Provides the management command to clean the file cache, optionally specifying a non-default cache directory.

```bash
/path/manage.py cleanfilecache
/path/manage.py cleanfilecache /path/to/non-default/cache/dir
```

--------------------------------

### File Cache Manual Invalidation and Update

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Demonstrates manual invalidation and updating of cached items using the file cache.

```python
top_articles.invalidate(some_category)
# or
top_articles.key(some_category).set(some_value)
```

--------------------------------

### File Cache Decorators

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Illustrates using `@file_cache.cached` and `@file_cache.cached_view` for file-based time-invalidated caching.

```python
from cacheops import file_cache

@file_cache.cached(timeout=number_of_seconds)
def top_articles(category):
    return ... # Some costly queries

@file_cache.cached_view(timeout=number_of_seconds)
def top_articles(request, category):
    # Some costly queries
    return HttpResponse(...)
```

--------------------------------

### Django Template Cache Fragment

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Demonstrates the usage of `{% cached_as %}` template tag for caching fragments in Django templates.

```django
{% load cacheops %}

{% cached_as <queryset> <timeout> <fragment_name> [<extra1> <extra2> ...] %}
    ... some template code ...
{% endcached_as %}
```

--------------------------------

### Fix Pickle Protocol for Cross-Version Cacheops

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Allows cacheops cache to be used across different Python versions by fixing the pickle protocol version.

```python
import pickle

class CACHEOPS_SERIALIZER:
    dumps = lambda data: pickle.dumps(data, 3)
    loads = pickle.loads
```

--------------------------------

### Degrade Gracefully on Redis Fail

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Configure cacheops to degrade gracefully when Redis fails by setting the CACHEOPS_DEGRADE_ON_FAILURE option to True.

```python
CACHEOPS_DEGRADE_ON_FAILURE = True
```

--------------------------------

### Configure Cacheops Serializer

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Sets the serializer for cacheops. 'dill' can serialize more complex objects like anonymous functions.

```python
CACHEOPS_SERIALIZER = 'dill'
```

--------------------------------

### Mass Updates with Cacheops

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Introduces the `invalidated_update` method for performing mass updates on QuerySets while ensuring cache invalidation.

```python
qs.invalidated_update(...)
```

--------------------------------

### Cache View with Dynamic Extra Parameter

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Provide a function to the 'extra' parameter of @cached_view_as to dynamically include request-specific information in the cache key, allowing for personalized caching.

```python
from cacheops import cached_view_as

@cached_view_as(News, extra=lambda req: req.user.is_staff)
def news_index(request):
    # ... add extra things for staff
    return render(...)
```

--------------------------------

### Configure Default Caching Profile in Django Cacheops

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Sets default caching parameters like timeout using CACHEOPS_DEFAULTS, which can then be overridden for specific models in the CACHEOPS setting. This simplifies configuration for common caching behaviors.

```python
CACHEOPS_DEFAULTS = {
    'timeout': 60*60
}
CACHEOPS = {
    'auth.user': {'ops': 'get', 'timeout': 60*15},
    'auth.*': {'ops': ('fetch', 'get')},
    'auth.permission': {'ops': 'all'},
    '*.*': {},
}
```

--------------------------------

### Run Cacheops Reap Conjunctions Management Command

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Cleans up conjunction keys of expired cache keys in Redis that may cause slow invalidation or extra memory usage. Allows custom chunk size and minimum conjunction set size.

```bash
./manage.py reapconjs --chunk-size=100 --min-conj-set-size=10000  # with custom values
./manage.py reapconjs                                             # with default values (chunks=1000, min size=1000)
```

--------------------------------

### Cached Function with Extra Arguments

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Shows how to use the `extra` argument with the `@cached` decorator for caching based on additional parameters, useful for nested functions.

```python
from cacheops import cached
import json

@property
def articles_json(self):
    @cached(timeout=10*60, extra=self.category_id)
    def _articles_json():
        ... # Fetch articles
        return json.dumps(...)

    return _articles_json()
```

--------------------------------

### Use Custom Cache Tag in Django Template

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Shows how to load and use a custom template tag (`cache_menu`) within a Django template. The custom tag, defined using cacheops, caches the enclosed template fragment based on the provided arguments.

```django
{% load mycachetags %}

{% cache_menu "top" %}
    ... the top menu template code ...
{% endcache_menu %}

... some template code ..

{% cache_menu "bottom" %}
    ... the bottom menu template code ...
{% endcache_menu %}
```

--------------------------------

### Invalidate Model and All Cache

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Demonstrates how to invalidate all queries for a specific model and how to flush the entire Redis cache database.

```python
from cacheops import invalidate_model, invalidate_all

invalidate_model(Article)     # invalidates all queries for model
invalidate_all()              # flush redis cache database
```

--------------------------------

### Prevent Dog-pile Effect with Cacheops Locking

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Demonstrates how to prevent the dog-pile effect (multiple threads/processes performing the same heavy task simultaneously) using cacheops' locking mechanism. This can be applied to functions decorated with `@cached_as` or when iterating over querysets.

```python
@cached_as(qs, lock=True)
def heavy_func(...):
    # ...

for item in qs.cache(lock=True):
    # ...
```

--------------------------------

### Time-Invalided Cache Decorators

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Demonstrates how to use `@cached` and `@cached_view` decorators to cache function and view results for a specified duration.

```python
from cacheops import cached, cached_view

@cached(timeout=number_of_seconds)
def top_articles(category):
    return ... # Some costly queries

@cached_view(timeout=number_of_seconds)
def top_articles(request, category=None):
    # Some costly queries
    return HttpResponse(...)
```

--------------------------------

### Connect Cache Read Signal for Stats

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Connects a stats collector function to the cacheops 'cache_read' signal to increment statsd counters for cache hits and misses.

```python
from cacheops.signals import cache_read
from statsd.defaults.django import statsd

def stats_collector(sender, func, hit, **kwargs):
    event = 'hit' if hit else 'miss'
    statsd.incr('cacheops.%s' % event)

cache_read.connect(stats_collector)
```

--------------------------------

### Disable Cacheops for Testing

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Temporarily disable all cacheops functionality for testing purposes using Django's override_settings decorator.

```python
from django.test import override_settings

@override_settings(CACHEOPS_ENABLED=False)
def test_something():
    # ...
    assert cond
```

--------------------------------

### Enable Cacheops Insideout Mode

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Enables 'insideout' mode for cacheops, where cache values contain checksums of random stamps stored in conjunction keys.

```python
CACHEOPS_INSIDEOUT = True
```

--------------------------------

### Manual Cache Invalidation and Update

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Illustrates how to manually invalidate cached function results or update cache entries using generated methods.

```python
top_articles.invalidate(some_category)
top_articles.key(some_category).set(new_value)
```

--------------------------------

### Manage.py Invalidate Commands

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Shows the usage of the 'invalidate' management command for invalidating specific objects, models, or all models within an app.

```bash
./manage.py invalidate articles.Article.34  # same as invalidate_obj
./manage.py invalidate articles.Article     # same as invalidate_model
./manage.py invalidate articles   # invalidate all models in articles
./manage.py invalidate all # FLUSHES cacheops redis database
```

--------------------------------

### Cache Class-Based View

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Cache class-based views by applying the @cached_view_as decorator to the view's as_view() method. This allows leveraging caching for CBVs.

```python
from django.views.generic import ListView
from cacheops import cached_view_as

class NewsIndex(ListView):
    model = News

news_index = cached_view_as(News)(NewsIndex.as_view())
```

--------------------------------

### Cache View with @cached_view_as

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Cache the output of a view function using the @cached_view_as decorator. The cache key is constructed using the request path and optionally other parameters.

```python
from cacheops import cached_view_as

@cached_view_as(News)
def news_index(request):
    # ...
    return render(...)
```

--------------------------------

### Manually Cache Queryset

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Force a specific queryset to be cached by calling the .cache() method on it. This allows explicit control over which operations are cached.

```python
Article.objects.filter(tag=2).cache()
```

--------------------------------

### Override Queryset Cache Timeout

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Set a custom cache timeout for a specific queryset by passing the 'timeout' argument to the .cache() method.

```python
qs = Article.objects.filter(visible=True).cache(timeout=300)
```

--------------------------------

### Cache Function with Granular Invalidation

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Cache function results with more granular invalidation by using a local function and passing arguments that affect the cache key. The 'extra' parameter can be used to include function arguments in the cache key.

```python
from cacheops import cached_as

def articles_block(category, count=5):
    qs = Article.objects.filter(category=category)

    @cached_as(qs, extra=count)
    def _articles_block():
        articles = list(qs.filter(photo=True)[:count])
        if len(articles) < count:
            articles += list(qs.filter(photo=False)[:count-len(articles)])
        return articles

    return _articles_block()
```

--------------------------------

### Invalidate Cached View

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Explains how to invalidate a cached view by providing the absolute URI and relevant arguments.

```python
top_articles.invalidate('http://example.com/page', some_category)
```

--------------------------------

### Disable Caching for Queryset

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Use the .nocache() method as a shortcut to disable automatic caching for a particular queryset. Subsequent operations on this queryset will hit the database.

```python
qs = Article.objects.filter(visible=True).nocache()
qs1 = qs.filter(tag=2)       # hits database
qs2 = qs.filter(category=3)  # hits it once more
```

--------------------------------

### Cache Function with Multiple Invalidation Models

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Cache function results based on changes to multiple models or querysets by passing them as arguments to the @cached_as decorator.

```python
from cacheops import cached_as

@cached_as(Article.objects.filter(public=True), Tag)
def article_stats():
    return {...}
```

--------------------------------

### Turn Off Invalidation Temporarily

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Provides methods to temporarily disable cache invalidation using a context manager or a decorator, useful for batch operations.

```python
from cacheops import no_invalidation

with no_invalidation:
    # ... do some changes
    obj.save()
```

```python
from cacheops import no_invalidation

@no_invalidation
def some_work(...):
    # ... do some changes
    obj.save()
```

```python
from cacheops import invalidate_obj, invalidate_model, no_invalidation

try:
    with no_invalidation:
        # ...
finally:
    invalidate_obj(...)
    # ... or
    invalidate_model(...)
```

--------------------------------

### Invalidate Cache Fragment in Django

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Demonstrates how to invalidate a specific cached fragment in Django using the `invalidate_fragment` function from the cacheops library. This is useful when the content of a cached template fragment needs to be updated or cleared.

```python
from cacheops import invalidate_fragment

invalidate_fragment(fragment_name, extra1, ...)
```

--------------------------------

### Cache Function Results with @cached_as

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Cache the results of a function using the @cached_as decorator. The cache is invalidated on changes to the specified model (e.g., Article).

```python
from cacheops import cached_as
from django.db.models import Count

@cached_as(Article, timeout=120)
def article_stats():
    return {
        'tags': list(Article.objects.values('tag').annotate(Count('id'))),
        'categories': list(Article.objects.values('category').annotate(Count('id')))
    }
```

--------------------------------

### Invalidate Specific Object Cache

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Manually invalidate the cache for all queries affected by a specific object using the invalidate_obj function.

```python
from cacheops import invalidate_obj

invalidate_obj(some_article)
```

--------------------------------

### Invalidate All Caches

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Clear all cached data managed by cacheops using the invalidate_all function. Use this with caution as it affects all cached items.

```python
from cacheops import invalidate_all

invalidate_all()
```

--------------------------------

### Invalidate Model Cache

Source: https://github.com/suor/django-cacheops/blob/master/README.rst

Invalidate all caches associated with a specific model using the invalidate_model function. This is a broader invalidation than invalidate_obj.

```python
from cacheops import invalidate_model

invalidate_model(Article)
```

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