哈希文件用于静态内容Web服务器

Question

I am writting my own static web content delivery routines. For caching I plan to include hashes in URLs like

/static/file.MD5HASH.png

I am developing in a static, compiled language. I read https://docs.djangoproject.com/en/dev/ref/contrib/staticfiles/#cachedstaticfilesstorage and https://gist.github.com/3207357

Now my mental problem is how to determine efficiently the hash of a file? I will not calculate the hash upon every request to the server. So I need some caching.

I could write a helping program which takes the path to the static content, recursively calculates the hash and stores the result as

filename.png HASH

in a file called .cache.hash.lookup. This file is loaded on web server start and statet on every request so when a static file is about to be served it will look it up in the cache and if the cache is outdated, re-load the cache.

Is this feasible? Please I do not need advice how to do it using framework X as I would like to understand it and write my own routines.

Answer 1

Reading your link, the idea there is to store multiple versions of the same resource, so adding the hash to the filename happens when you insert a new file.

Your HTTP server can be dumb and just look up files by name. (another advantage I see is you can blindly respond with "304 Not changed" to any conditional request, as the hash in the filename acts as the etag.)

Or am I missing something?