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HTTP Caching: Difference between revisions
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(Created page with "One of the often overlooked superpowers of HTTP is the built in support for caching. This allows you to only spend the effort of generating a response every so often inste...") |
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== Time Based Caching == | == Time Based Caching == | ||
An easy way to implement caching is by specifying that a response is valid for a certain amount of time. For example if your resource is static and the same for all users you can set the following [[Cache-Control | An easy way to implement caching is by specifying that a response is valid for a certain amount of time. For example if your resource is static and the same for all users you can set the following [[Cache-Control header]]: <code>Cache-Control: public,maxage=300</code> This will keep the resource in your cache for five minutes. | ||
== ETag Based Caching == | == ETag Based Caching == | ||
If it is easy to generate a unique identifier that always changes when the response changes you can use that as an ETag identifier. This is done using the [[ETag Header]]: | If it is easy to generate a unique identifier that always changes when the response changes you can use that as an ETag identifier. This is done using the [[ETag Header]]: | ||
ETag: W/"my-unique-identifier" | |||
Cache-Control: public,maxage=5,must-revalidate | |||
This example will ask the cache to keep serving this response to requests coming in in the next 5 seconds. If a matching request comes in after the five seconds the cache will check whether it still has the last version using the [[If-None-Match header]]. | This example will ask the cache to keep serving this response to requests coming in in the next 5 seconds. If a matching request comes in after the five seconds the cache will check whether it still has the last version using the [[If-None-Match header]]. | ||
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* Don't put data that changes independently into the same request. Instead use a resource that returns [[URL | URLs]] to the child requests and leverage HTTP2 and caching. | * Don't put data that changes independently into the same request. Instead use a resource that returns [[URL | URLs]] to the child requests and leverage HTTP2 and caching. | ||
* Instead of disabling caching, set the <code>maxage</code> to a low value like 5 seconds. | * Instead of disabling caching, set the <code>maxage</code> to a low value like 5 seconds. | ||
[[Category: Terminology]] | |||