CDN and mod_proxy

Question

I have enabled mod_proxy on my stack and I have a call (below). I am trying to determine what the impact is on the CDN and billing.

For instance:

http://domain.com/ID/SIZE/my-super-lengthy-SEO-url.jpg

 RewriteRule ^scan/([^/]+)/(s|l|xl)/(.*)$ http://cdn.domain.com/$1_$2.jpg [P,L]

Based upon the example above:

1. Are the CDN benefits still being used (ie TTL/caching)?
2. When using a cloud service (ie Rackspace/Amazon/etc) would the above call result in duplicate bandwidth charges?

Answer 1

I work for a Cloud CDN provider (Incapsula) so my answer is based only on my experience with this particular product.

Having said that:

1. The image will be cached by CDN.(ie all related acceleration benefits will still apply)
2. No, as there is only one resource loaded. (301 request requires close to 0 bandwidth)

I`m pretty sure (99%) my second answer will apply for all Cloud CDN providers.

Best, Igal.