Explore Jetty-free implementation of resource handler

[dzikoysk]

Context

Currently, our static files api directly depends on Jetty's resource handler. It's a bit painful, because this implementation is relatively complex itself (because it works directly on Jetty's API) and it's one of the main blockers before exploring the possibility to use other http servers.

Requirements

The new implementation should:

• Be fully compatible with current static API
• Cover security related concerns to filter out malicious requests
• Do not depend on Jetty and Jakarta EE servlet's API

[Jerbell]

Hi @dzikoysk What would it take for a simple implementation here? Like a ClasspathResourceHandler which took in the directory where the files are, the match/url path & headers added. Would it still be difficult? I've seen the JettyResourceHandler but it looks quite complicated. Overly complicated perhaps?

[dzikoysk]

Hey, I remember @zugazagoitia did some work on exploring this topic, so maybe he could add some extra feedback on what we actually need to cover that. I personally didn't touch this part of Javalin that much, because I don't really use this feature on my own.

[zugazagoitia]

There are two main issues expanding on the ones @dzikoysk mentioned in the OP:

• Not breaking compatibility with the current handling of routes. Any new implementation might break how files are resolved in the clients in unexpected or non-intuitive ways.
• I had some trouble also handling webjar resources, which required a bit of a messy implementation.

I've seen the JettyResourceHandler but it looks quite complicated.

You are completely right about this, it is more complicated than it should. If you have the time and will please give it a shot and see how far you get! I currently don't have the time to keep working on it unfortunately.

A minimal implementation should just implement the ResourceHandler interface and offer the same config and compressing functionality (precompressing can easily be added after).

Optimally we would in future versions implement smarter caching, but not a big issue now either. If you want to explore this further we're available also in Discord.