Low-Level cache API and Invalidation
Cache query results and bust stale keys.
Low-Level cache API and Invalidation is a free Django Academy lesson on CoddyKit — lesson 4 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Django Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Cache Anything You Like
The low-level cache API lets you store any Python object, like a query result, with full control over the key and timeout.
Import the cache Object
Reach for the shared cache object from django.core.cache to call its methods anywhere in your views or services.
from django.core.cache import cacheThe Cache-Aside Pattern
The classic flow is cache-aside: try the cache, and only run the slow query when the value is missing.
stats = cache.get("stats")
if stats is None:
stats = compute_stats()
cache.set("stats", stats, 300)get_or_set in One Call
Collapse that pattern with get_or_set, which returns the cached value or computes, stores, and returns it.
stats = cache.get_or_set("stats", compute_stats, 300)Store Many at Once
Use set_many to write several keys in a single round trip, which is faster than many separate set calls.
cache.set_many({"a": 1, "b": 2}, 300)Stale Data Is the Risk
Cached values can drift from the database. Removing an outdated entry so fresh data loads is called invalidation.
Delete a Key
Call delete with a key to drop one entry, forcing the next read to rebuild it from the source.
cache.delete("stats")Invalidate on Save
A reliable habit is to delete the affected key right after the data changes, so users never see the old version.
post.save()
cache.delete("post_" + str(post.id))Versioning Beats Deleting
Pass a version to set and get so bumping the number instantly retires a whole set of old keys at once.
cache.set("stats", data, version=2)Atomic Counters
Increase a numeric key safely with incr, perfect for view counts where several requests update the same value.
cache.incr("page_views")Clear Everything as a Last Resort
The clear method wipes the entire cache. It is a blunt tool, so save it for deploys, not for routine updates.
cache.clear()Quick Check
Let's confirm the cleanest way to read or compute a value.
Recap
You mastered the low-level API: cache-aside with get_or_set, then keep data fresh by deleting keys or bumping the version. 🎯
Frequently asked questions
Is the “Low-Level cache API and Invalidation” lesson free?
Yes — the full text of “Low-Level cache API and Invalidation” is free to read here on the web, and the Django Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Django Academy course, upgrade to CoddyKit PRO.
What will I learn in “Low-Level cache API and Invalidation”?
Cache query results and bust stale keys. You practise Django Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Django Academy?
No prior experience is required. Django Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 4 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Low-Level cache API and Invalidation” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Django Academy lesson?
Yes. Every Django Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Cache Backends and Redis
- Per-View and Per-Site Caching
- Template Fragment Caching
- Low-Level cache API and Invalidation