I need to call

app.UseStaticFiles( ... )

to customize the behavior, but I don't know where/when to put this in

Program.cs

. I'm guessing

.UseUmbraco()

already does this internally? I'm using the Umbraco 13 NuGet project template.

Hey, it's usually not recommended to add your own call to

.UseStaticFiles()

, however, there is an extension point where you can modify the settings! You can implement

IConfigureOptions<StaticFileOptions>

. I use this to add response cache headers to the output like this:

csharp
public class CachingStaticFileOptionsConfiguration : IConfigureOptions<StaticFileOptions>
{
    public void Configure(StaticFileOptions options)
    {
        options.OnPrepareResponse = ctx =>
        {
            // exclude requests to backoffice resources,
            //    because they already have finetuned headers
            if (IsUmbracoRequest(ctx.Context))
            {
                return;
            }

            Microsoft.AspNetCore.Http.Headers.ResponseHeaders headers = ctx.Context.Response.GetTypedHeaders();
            headers.CacheControl = new CacheControlHeaderValue
            {
                Public = true,
                MaxAge = TimeSpan.FromSeconds(Defaults.StaticAssetResponseCacheDuration),
                Extensions =
                    {
                        new NameValueHeaderValue("immutable")
                    }
            };
        };
    }

    private static bool IsUmbracoRequest(HttpContext context)
    {
        return context.Request.Path.StartsWithSegments("/umbraco");
    }
}

Would that work for you?

Wow, thanks! This looks perfect. Do you know where I can find the recommendation to not call

UseStaticFiles()

? I didn't find anything when searching.

Ah no, bad phrasing excuse me. It's in my experience a bad idea to call it yours3lf. Have had difficult to track down issues when adding the middleware myself

I never had issues with usage of UseStaticFiles, and i made not one package using it 🤔, so not sure what was your experience but there shouldn't be issue to call it even 1000 times in different places 🤔

Can you tell me more about you "made not one package using it"?

Mostly it was internal company framework packaged, so can't go in details sorry, but yeah I am usually person to find weird issues