how to Change wwwroot folder name in ASP.NET Core

By default ASP.NET Core's services are bound to a HostingEnvironment and a ContentRoot folder in which the application is installed. The ContentRoot is the folder where the application's binary resources and configuration files live. There's also a WebRoot folder and typically this is the wwwroot folder where the Web application expects static content to be served from. Static HTML files and CSS, Images and JavaScript resources typically live in this static wwwroot folder.

This is pretty accepted common ground and almost every ASP.NET Core application uses that same pattern. And this is totally fine for typical custom Web applications.

But if you want to serve content from other locations than the host folder or dynamically configure your application to process files from other locations, some additional setup is required. Turns out though, that ASP.NET Core makes this fairly easy via configuration once you find the right dials to tweak. Specifically various ASP.NET frameworks support specifying a FileProvider that determines where files are loaded from and by customizing paths it's relatively easy to serve content from other locations.

ASP.NET Core's File Providers

IFileProvider is a base interface that is used to - as the name suggests - provide files to the application. Files can come from different locations and rather than hard coding physical paths there are various file providers.

One of those providers is a PhysicalFileProvider which is used to specify a physical disk path from which to serve file resources. Other providers can serve files directly from embedded resources, from a stream or from custom data providers.

For loading content out of folders other than the default folder I'll use a PhysicalFileProvider and point it at an application provided path via commandline most commonly but any of the other configuration points.

Static Files from external Folders

My specific use case is to build a generic static file Web server with Live Reload functionality, that I can either run from a given folder or provide a --WebRootPath parameter to point at a folder to launch out of.

ASP.NET Core uses the StaticFiles middleware, so to serve static files out of a different folder we can configure the .UseStaticFiles() initialization.

.Net 6.x

program.cs

var builder = WebApplication.CreateBuilder(args);

// Look for static files in webroot
builder.WebHost.UseWebRoot("webroot");

var app = builder.Build();

.Net 5.x

in Startup.Configure():

WebRootPath = Configuration["WebRootPath"];  // from config/CommandLine/Env
if(string.IsNullOrEmpty(WebRootPath))
    WebRootPath = Environment.CurrentPath;
...
app.UseStaticFiles(new StaticFileOptions
{
    FileProvider = new PhysicalFileProvider(WebRoot),
    RequestPath = new PathString("")
});

One of the options of the StaticFiles middleware is to specify a file provider which determines which folder to use for static files to serve. This folder location is set as the root path, with the context.Request.Path appended to find the file to serve.

Here I assign a PhysicalFileProvider with a new root path. I also set the RequestPath to "" which is the Root Path - normally this defaults to /wwwroot which is the location in default ASP.NET Core project where static content is served from. But in this case I want my server to serve directly out of the root folder I specify via config or the command line - as provided by a WebRoot configuration switch. RequestPath is set to empty to use the root folder.

That's literally all it takes to create a generic static file server. You can now access any static content from the Web root on the port you specify:

http://localhost:5000

This is a very simple, yet powerful use case: doing literally nothing more than adding the StaticFile middleware into a new application and setting the path gives you a generic static file Web server.