Question

I have setup static files (css, images and js) files on a cloudfront distribution and am using the cloudfront URLs of the files to refer to them in the JSP files.
I have setup cache-control value to a max of one month.

Suppose if I modify the css/js files before cache expires and update the files in the cloudfront distribution after invalidating the original object.

What are the ways in which I can make sure that the browser fetches the updated file ?

Answer 1

Amazon recommends a technique they call “versioning” which basically means change the object’s filename when you change the object.

The CloudFront developer manual ( http://docs.amazonwebservices.com/AmazonCloudFront/latest/DeveloperGuide/index.html?ReplacingObjects.html ) describes it as follows:

We recommend that you use the common
technique of versioning to give
yourself better control of your
content. Versioning means that you
assign each object in the origin
server a version number. For example,
instead of calling the file image.jpg,
you call it image_1.jpg. Then when you
want to start serving a new version of
the file, you name that new file
image_2.jpg, and you update your links
to point to image_2.jpg. With
versioning, you do not have to wait
for an object to expire before you can
serve a new version of it.

Even though you might be versioning
your objects, we still recommend you
set an expiration date that you feel
is appropriate for your objects. For
more information see Object
Expiration.