batch-update-nginx-etag

set file mtime to content based etag value with nginx-etag

npm install -g batch-update-nginx-etag

find ./ | nginx-etag --filter '.js$'

this provides a command that sets the modified time of all matching files to the value of the first 32 bits of it's md5 sum.

why

nginx builds the etag from the file's mtime and the number of bytes. if you serve the same static files from a distributed set of nginx servers the mtime has to match or your users will download content they already have.