CODEWITHSUNDEEP
apachehttp.htaccesscaching
Umesh Awasthi
Umesh Awasthi

Reputation: 23587

mod_expires in apache htaccess

I am learning about apache and its various modules, currently i am confused about mod_expires. What i read so far is that using this module we can set future expiry header for static files so that browser need not to request them each time.

I am confused about the fact that if some one change css/js or any image file in between, how will browser come to know about it since we have already told the browser that this is not going to change say for next 1 year.

Thanks in advance

Upvotes: 3

Views: 713

Answers (1)

Silenteh
Silenteh

Reputation: 516

It may not be possible for all provided content on your HTTP server, but you can simply change the name of the file to update a file on the client side from the server. At that point, the browser will download the new content.

Sometimes, for websites with less traffic it is far more functional to set the cache to a much lower value.

An expiration of 365 days should always be used with caution, and the fact that you can set an expiration of 1 year does not mean you always have to do it. In other words, do not fall prey to premature optimization.

A good example of setting cache expiration to 1 year are countries' flags, which are not likely to change. Also, be aware that with a simple browser refresh of a page, the client can discard the local cache and download the content again from the origin.

A good and easy way of testing all this is to use Firefox with Firebug. With this extension, you can analyze requests and responses.

Here you can find the RFC specifications.

Upvotes: 2

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