What is Caching?Caching is the process of temporarily storing copies of data in a faster storage location to improve access speed and system performance.
Let take an simple example of it suppose Caching is like keeping your favorite snacks in a kitchen drawer; instead of going to the store every time you want a snack, you can quickly grab one from the drawer.
Here are some benefits of it in our web service
Caching can be found in various locations and systems, including:
Terminology we uses over here are :
- Client
- Origin Server
- Stale Content – It refers to expire content.
- Fresh Content – It refers to new content.
- Cache Validation – It refers to process check the validity of cache content and get it updated if it get expires.
- Cache Invalidation – It refers that it remove all stale content (remove all expired content)
How does content get cached ?
HTTP Headers play an crucial role over here, client request for the data then server sent the file with some headers.
Let discuss about caching headers:
- Expires
- Pragma
- Cache-control
Expires and Pragma used in the HTTP 1.0 but everything that can be dine by this two are done by cache-control also that is mostly preferred in HTTP 1.1.
Expire Header:-
→ Absolute expiry date
→ Can’t be more than a year
→ Clock have to be in sync
Pragma Header(only have value : no cache):-
→ To prevent caching
→ HTTP 1.0 depreciated header
→ cache-control should be preferred
Cache-Control Header:-
It is an Multi value header
Cache-Control ValueExplanation
publicAnyone can cache this response, including browsers and shared caches.
privateOnly the user’s browser can cache this response; shared caches cannot.
no-cacheThe response can be cached, but must be revalidated with the server before being used again.
no-storeThe response cannot be cached at all; it must be fetched from the server every time.
max-age=<seconds>The response can be cached and reused for the specified number of seconds before it expires.
s-maxage=<seconds>Similar to max-age, but specifically for shared caches like CDNs, overriding other age settings.
max-stale[=<seconds>]The client can accept a stale response if it’s within the specified time limit.
min-fresh=<seconds>The client wants a fresh response that is still valid for at least the specified number of seconds.
stale-while-revalidate=<seconds>The cache can use stale responses while it checks for a fresh one in the background for the given time.
stale-if-error[=<seconds>]If fetching a fresh response fails, the client will accept a stale one for the specified duration.
must-revalidateOnce a cached response becomes stale, it must be revalidated with the server before use.
proxy-revalidateSimilar to must-revalidate, but only applies to shared caches and not private ones.
immutableThe response body will not change over time, so it can be cached indefinitely without revalidation.
no-transformThe response should not be altered or transformed by any intermediate caches.
only-if-cachedThe client will only use cached responses and will not make a network request if the data is not cached.
Validators Headers:
It check the cache content weather it still be used or we have to update.
- etag (entity tag)
- if-none-match
- last-modified
- if-modified-since
I hope you enjoyed this blog and found valuable insights into the importance of caching for web services. By enhancing performance, reducing load times, and optimizing resource usage, caching plays a crucial role in delivering a seamless user experience. As you implement caching strategies, you’ll not only improve your website’s efficiency but also boost user satisfaction and engagement. Thank you for reading, and I look forward to sharing more helpful information with you in the future!
Source: hashnode.com
