Invalidating the HTTP Cache on read only front servers

We have a CMS system and in the production mode a number of servers only have read-only access to the content (with a few exceptions) and t开发者_StackOverflow中文版he editors for the site work on the content on servers behind it (which are not available to the public).

We're caching the content quite a long time on the front servers, but sometimes we want the content the editors publish to be available for visitors instantly. What is best practice for invalidating the cache in those cases?

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Doesn't the answer depend on the front-end servers and their APIs ?

Assuming the cache is only in the front-end servers, if they expose a method to clear a part of the cache, call it.

If you used the HTTP headers to tell the browser and intermediate proxies that the content can be cached for some time, I don't see a way to invalidate this at their level.

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The best way, I guess, is to invalidate cache within the CMS core.