Attempt to add cachebusting based on file modification times or file contents.
Works in my limited use-case. Not sure if it will work in every case. Still needs unit tests.
Added cache busting option 'expire'
Merge remote-tracking branch 'origin/master' into auto-cache-bust
What is the advantage of providing these different strategies? Why not just provide one?
I added the last-modified-time mostly because it was easy to add and because a similar feature is available in the WebAssets library (which I also used as inspiration for the options name).
The last modified time is faster and should generally work adequately, especially during development. However in our deployment scenario (multiple machines and hosted from S3) the modified time of different machines will be different due to the deployment process not starting at the exact same time. This would result in separate filenames in S3 for each machine which in term would lead to clients having to cache multiple versions if the loadbalancer directs them to a different machine.
alternative implementation for #190
Closing in favor of #297