Skip to main content

Static File handling in ASP.NET Core 9.0

I know, I know, .NET 10 is already in preview and I am still catching up on what was added to .NET 9.0. Today while upgrading an older application to .NET 9, I decided to have a look at the new static file handling introduced in .NET 9 through the MapStaticAssets feature.

Static File middleware (before .NET 9)

Before .NET 9, static files(Javascript, CSS, images, …) were handled through the UseStaticFiles middleware

This middleware is still there as the new MapStaticAssets feature does not support all the features that the original middleware had.

From the documentation:

MapStaticAssets (starting from .NET 9)

Now enough about what is NOT supported, let’s talk about why you should use this feature. Start by replacing the usage UseStaticFiles by MapStaticAssets:

MapStaticAssets provides the following advantages compared to UseStaticFiles:

  • Build time compression for all the assets in the app. It uses gzip during development and gzip + brotli during publishing. All assets are compressed with the goal of reducing the size of the assets to the minimum.
  • The ETags for each resource are the Base64-encoded string of the SHA-256 hash of the content. This ensures that the browser only redownloads a file if its contents have changed.
  • Dynamic compression is not need on the web server level simplifying configuration and performance as assets are compressed at build time.

Let’s see it in action…

I first start my application with the original UseStaticFiles implementation. Here is a screenshot of the response headers:


Let’s compare this with the same file served through MapStaticAssets:

Do you notice the differences?

The content-encoding is set to gzip (in dev) and the e-tag is calculated differently using fingerprinting. And of course the size is also smaller.

Nice!

More information

Map static files in ASP.NET Core | Microsoft Learn

What's new in ASP.NET Core 9.0 | Microsoft Learn

Enabling dynamic compression in IIS

Labels:

Popular posts from this blog

.NET 8–Keyed/Named Services

A feature that a lot of IoC container libraries support but that was missing in the default DI container provided by Microsoft is the support for Keyed or Named Services. This feature allows you to register the same type multiple times using different names, allowing you to resolve a specific instance based on the circumstances. Although there is some controversy if supporting this feature is a good idea or not, it certainly can be handy. To support this feature a new interface IKeyedServiceProvider got introduced in .NET 8 providing 2 new methods on our ServiceProvider instance: object? GetKeyedService(Type serviceType, object? serviceKey); object GetRequiredKeyedService(Type serviceType, object? serviceKey); To use it, we need to register our service using one of the new extension methods: Resolving the service can be done either through the FromKeyedServices attribute: or by injecting the IKeyedServiceProvider interface and calling the GetRequiredKeyedServic...
Read more

Azure DevOps/ GitHub emoji

I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.
Read more

Kubernetes–Limit your environmental impact

Reducing the carbon footprint and CO2 emission of our (cloud) workloads, is a responsibility of all of us. If you are running a Kubernetes cluster, have a look at Kube-Green . kube-green is a simple Kubernetes operator that automatically shuts down (some of) your pods when you don't need them. A single pod produces about 11 Kg CO2eq per year( here the calculation). Reason enough to give it a try! Installing kube-green in your cluster The easiest way to install the operator in your cluster is through kubectl. We first need to install a cert-manager: kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.14.5/cert-manager.yaml Remark: Wait a minute before you continue as it can take some time before the cert-manager is up & running inside your cluster. Now we can install the kube-green operator: kubectl apply -f https://github.com/kube-green/kube-green/releases/latest/download/kube-green.yaml Now in the namespace where we want t...
Read more