I was looking around last night at different CDN solutions out there. Everything from Amazon’s new CloudFront to CacheFly to Limelight and a couple others.
All of them have different features and levels of performance but the one thing I really want to be able to do is on-demand invalidation. Regular TTLs are fine for static items like images, css, js, videos and the like. But what about regular HTML files? Most of today’s websites these days have pages that are dynamic in some way or another. What I would like to be able to do is generate a page, cache it in a CDN and then if/when needed tell the CDN to remove that file immediately. Not hours from now. From what I can tell, none of the solutions I looked at had that ability. CloudFront has a minimum TTL of 24 hours. Limelight is just over an hour. I couldn’t find the info on CacheFly.
Where I find this most appropriate is an ecommerce app. Say you have a product page that you want to cache. Makes sense, but what if you want to be proactive to the customer and let them know when that item is not longer in stock instead of waiting until they add it to the cart? That isn’t a very good customer experience.
I specifically mention ecommerce because one, I’ve worked for a big one and two it has been shown that reductions of mere milliseconds in latency increases revenue.
Surely there is a solution out there that can do this?
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