Does CloudCDN support the serving of Brotli encoding?

Question

My company is thinking of moving from AWS to GCP. One of the feature we want to support from CloudCDN is brotli encoding. We have a techstack that will bundle our javascript into 3 files:

chunk.js
chunk.js.gz
chunk.js.br

If CloudCDN receives client request headers Accept-Encoding: br, gzip is CloudCDN smart enough to serve up Brotli file? Moreover, will it be cached? If not, are there any other approaches in achieving this in CloudCDN.

AWS Cloudfront only offers this feature with the use of 2 lamdbas. Which I think is a bad idea.

Answer 1

Yes, Cloud CDN can cache all 3 representations and serve the correct one based on the client's Accept-Encoding header so long as the response from your origin server includes a Vary: Accept-Encoding header. There's more information at https://cloud.google.com/cdn/docs/caching#vary_headers.

Update:

I didn't realize you were using a Cloud Storage bucket as the origin. Unfortunately, neither Cloud CDN nor Cloud Storage have functionality that will rewrite client requests for /chunk.js to /chunk.js.br based on whether the client supports Brotli. I agree that would useful, so I filed an internal feature request.

When an origin server such as nginx is configured to select the appropriate file, Cloud CDN needs to go back to the origin server only on a cache miss. So long as the origin server's responses contain a Vary: Accept-Encoding header, Cloud CDN can serve cache hits directly from the edge by comparing the client's Accept-Encoding request header with the Accept-Encoding value specified when the response was cached. Clients that specify Accept-Encoding: br, gzip will be served from one cache entry while clients that specify Accept-Encoding: gzip will be served from another.