Static Files

• By default, an asp.net core application will not serve static files

• The default directory for static files is wwwroot and this directory must be in the root project folder

• In order to serve static files the request processing pipeline must have the required middleware that can serve the Static Files.

• We will add the UseStaticFiles() middleware to our application's request processing pipeline as shown below.

  public static void Main(string[] args)
  {
      var builder = WebApplication.CreateBuilder(args);
      var app = builder.Build();
  
      app.UseStaticFiles();
      
      app.Run();
  }

• Now lets add the wwwroot folder with the folowing files:

  📁 StaticFiles
  └──📂 wwwroot
      └──📂 images
          ├── RedCar.jpg
          ├── YellowCar.jpg
          ├── GrayCar.jpg
          └── GreenCar.jpg

  We can navigate to each file via the URL: https://localhost:<port>/images/RedCar.png

• Most web applications have a default document/file which displayed when a user visits the root URL of your application

• To be able to serve default file, (like default.html), we have to plug in the UseDefaultFiles() middleware in our application's request processing pipeline.

• UseDefaultFiles must be called before UseStaticFiles to serve the default file. 

• The following are the default files which UseDefaultFiles middleware looks for:

  • index.htm
  • index.html
  • default.htm
  • default.html

• If we want to use another document like foo.html as the default, we can use the Option class and supply it to the middleware:

      public static void Main(string[] args)
      {
          var builder = WebApplication.CreateBuilder(args);
          var app = builder.Build();
  
          DefaultFilesOptions options = new DefaultFilesOptions();
          options.DefaultFileNames.Clear();
          options.DefaultFileNames.Add("foo.html");
  
          app.UseDefaultFiles(options);
          app.UseStaticFiles();
  
          app.Use(async (context, next) =>
          {
              await context.Response.WriteAsync("Hello from first middlware!\n");
              await next();
          });
  
          app.Run(async context =>
          {
              await context.Response.WriteAsync("Hello from second middlware!");
          });
  
          app.Run();
      }

• UseFileServer combines the functionality of UseStaticFiles, UseDefaultFiles and UseDirectoryBrowser middleware.

• DirectoryBrowser middleware, enables directory browsing and allows users to see files within a specified directory. We could replace UseStaticFiles and UseDefaultFiles middlewares with UseFileServer Middleware.

• The pattern to add middleware is as follows:

  • In most cases we add middleware using the extension methods that start with the word USE
  • If we want to customize these middleware components, we use the respective OPTIONS object

  Middleware	Options Object
  UseDeveloperExceptionPage	DeveloperExceptionPageOptions
  UseDefaultFiles	DefaultFilesOptions
  UseStaticFiles	StaticFileOptions
  UseFileServer	FileServerOptions

Bibliography:

1. Static Files in ASP.NET Core