Cache Basic Operation

When Cache is Not Used #

Even if data hasn't changed, it must be continuously downloaded over the network.
Internet networks are very slow and expensive.
Browser loading speed is slow.
Slow user experience.

Cache Applied #

First Request

HTTP/1.1 200 OK
Content-Type: image/jpeg
cache-control: max-age=60
Content-Length: 34012

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Cache Applied

Thanks to caching, there's no need to use the network during the cacheable period.
Reduces expensive network usage.
Browser loading speed is very fast.
Fast user experience.

Third Request - Cache Expiration When a request is made, the browser cache validates the expiration time. If the time has passed, it downloads the data again, like the first request, and stores it in the cache.

If the cache expiration time is exceeded, the data is re-queried from the server, and the cache is updated.
At this point, a network download occurs again.