Static Web Assets cache busting mechanism

[stefanloerwald]

Is your feature request related to a problem? Please describe.

Browser cache files (partially depending on the server settings), which can lead to the situation that a scoped CSS file changed, but this is not picked up, because the file name didn't change. Replacing ProjectName.styles.css by ProjectName.styles.css?hash=123 doesn't produce the usual cache-busting mechanism, because the contents of that file (e.g. @import _content/library/library.bundle.scp.css) didn't change, only the file referenced by the import changed in content.

Describe the solution you'd like

Would it be possible to automatically calculate a file hash of the scoped CSS parts and import them with @import '_content/library/library.bundle.scp.css?hash=123';?

[javiercn]

@stefanloerwald thanks for contacting us.

We don't currently have a solution for this, however you can achieve this today with a middleware that checks for requests to files with the right extensions and adds the appropriate caching headers.

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[mkArtakMSFT]

@stefanloerwald can you please also share how you're hosting your site? Is it Blazor WebAssembly of Server project?
Also, are you looking for this for dev-time or post publishing?

[stefanloerwald]

Certainly! I'm actually maintaining a few sites with different hosting models. The one that this is causing an inconvenience at the moment is a Blazor server project behind an nginx reverse proxy. The caching headers are set by nginx for the static assets, so I need to work client-side to make sure I fetch the new version.

The solution I proposed doesn't seem too complicated to implement, and I would even try to do it myself, if there is consensus that it's a good idea without negative impact for users. What does the blazor team think about it?

[rogihee]

Just FYI, I'm also running into this issue. This is for production in a Blazor WebAssembly hosted (multiple apps) solution, with scoped CSS coming from private feed NuGet Razor Class libraries.