How do I exclude a folder from ASP.NET Core's static files?

Question

I have a folder under "wwwroot" that I don't want to include when returning static files.

I want to return various directories under "wwwroot" (for instance "wwwroot/images") and this middleware step enables that:

app.UseStaticFiles(); 

I can pass this StaticFileOptions to configure what's returned.

I want to exclude a directory (for instance "wwwroot/node_modules") and not allow any statif files to be served from that.

There doesn't appear to be a filter I can use on StaticFileOptions - how should I apply that filter?

Answer 1

Don't look for an option on the static files middleware - instead any middleware can be filtered using MapWhen or UseWhen. This allows you to only register the middleware for routes where a condition is passed.

For instance, to exclude "wwwroot/node_modules":

app.UseWhen(
    context => !context.Request.Path.StartsWithSegments("/node_modules"),
    appBuilder => appBuilder.UseStaticFiles());

This will now only apply the static files middleware when the route doesn't start with "/node_modules".

• UseWhen falls through to the next middleware if it fails
• MapWhen only goes on to the next middleware if the context filter applies