A static file is a web resource such as an image, JavaScript file, or CSS stylesheet served directly from disk rather than generated for each request. In ASP.NET Core, static files normally live in the wwwroot folder and are returned by static-file middleware. section 4.2.2
ASP.NET Core handles static-file requests in a small, focused pipeline:
- UseStaticFiles adds StaticFileMiddleware to the application pipeline. section 4.2.2
- The middleware checks wwwroot for the requested path and returns the file when it exists. section 4.2.2
- Files outside wwwroot are not served by default, helping prevent unintended access to other application folders. section 4.2.2
- A missing file produces an HTTP 404 response instead of a file response. section 4.2.2
Serving an image
Place moon.jpg in wwwroot and configure the application with app.UseStaticFiles();. A request for /moon.jpg is handled by StaticFileMiddleware and returns the image. A request for /missing.jpg returns 404. section 4.2.2
Listing 4.2 Program.cs for a static-file middleware pipeline
WebApplicationBuilder builder = WebApplication.CreateBuilder(args);
WebApplication app = builder.Build();
app.UseStaticFiles(); #1
app.Run();
#1 Adds the StaticFileMiddleware to the pipeline
The minimal Program.cs listing shows that a static-file application needs only WebApplication construction, UseStaticFiles, and app.Run. section 4.2.2
