VersionedFileProvider is a simple and lightweight IFileProvider wrapper for ASP.NET Core that allows you to remove or transform certain part of the file path. The package also expose a more generalized IPathTransformFileProvider and BasePathTransformFileProvider if you want a different path transformation.

ASP.NET Core provides asp-append-version attribute so you can "drop" file cache (either browser cache or server cache or even services like Cloudflare cache) of CSS and Javascript files. However, with ES6 module import, this does not work:

// Content of /js/app.js

import { Common } from "./../common.js"; // Cannot use asp-append-version here

In development machine, it is not a problem to disable cache. However, for production environment, there is no simple way to clear it without modifying every Javascript file. That's why I think of appending a manual version on the top file path only:

<script type="module" src="~/js/v1/app.js" asp-append-version="true"></script>

This way, when you increase the version in the path, all the modules' paths are updated accordingly. However you need a way to serve such files when in reality, the server file system only contains /js folder.

Nuget package:

Install-Package BibliTech.VersionedFileProvider

Note: the library itself is very simple. If you don't want to include external reference, simply copy the content of VersionedFileProvider.cs and BasePathTransformFileProvider.cs.

You can check the Demo project to see how it is used.

VersionedFileProvider accepts an underlying IFileProvider. You can also use a folder path string, it will automatically create a PhysicalFileProvider for that folder. In usual case, you will want to use WebRootFileProvider for that.

var versionedFileProvider = new VersionedFileProvider(env.WebRootFileProvider);
app.UseStaticFiles(new StaticFileOptions()
{
    FileProvider = versionedFileProvider,
});

If you want asp-append-version to work with this custom FileProvider, you will need to set it to IWebHostEnvironment.WebRootFileProvider. It is confirmed by the ASP.NET Core team.

env.WebRootFileProvider = versionedFileProvider;

By default, VersionedFileProvider uses a RegEx and simply remove every path segment that matches with it:

public Regex VersionRegex { get; set; } = new Regex(@"^v[0-9\.]+");

The default version match anything that starts with v and follows by 0-9 and dot (.) character, so your path is safe if you happen to have something like version or variant. You can change the VersionRegex property, or implement a FileProvider yourself by extending BasePathTransformFileProvider and override TransformSubpath method.