c# - How to get absolute path in ASP.Net Core alternative way for Server.MapPath

Question

How to get absolute path in ASP net core alternative way for Server.MapPath

I have tried to use IHostingEnvironment but it doesn't give proper result.

IHostingEnvironment env = new HostingEnvironment();
var str1 = env.ContentRootPath; // Null
var str2 = env.WebRootPath; // Null, both doesn't give any result 

I have one image file (Sample.PNG) in wwwroot folder I need to get this absolute path.

Answer 1

As of .Net Core v3.0, it should be IWebHostEnvironment to access the WebRootPath which has been moved to the web specific environment interface.

Inject IWebHostEnvironment as a dependency into the dependent class. The framework will populate it for you

public class HomeController : Controller {
    private IWebHostEnvironment _hostEnvironment;

    public HomeController(IWebHostEnvironment environment) {
        _hostEnvironment = environment;
    }

    [HttpGet]
    public IActionResult Get() {
        string path = Path.Combine(_hostEnvironment.WebRootPath, "Sample.PNG");
        return View();
    }
}

You could go one step further and create your own path provider service abstraction and implementation.

public interface IPathProvider {
    string MapPath(string path);
}

public class PathProvider : IPathProvider {
    private IWebHostEnvironment _hostEnvironment;

    public PathProvider(IWebHostEnvironment environment) {
        _hostEnvironment = environment;
    }

    public string MapPath(string path) {
        string filePath = Path.Combine(_hostEnvironment.WebRootPath, path);
        return filePath;
    }
}

And inject IPathProvider into dependent classes.

public class HomeController : Controller {
    private IPathProvider pathProvider;

    public HomeController(IPathProvider pathProvider) {
        this.pathProvider = pathProvider;
    }

    [HttpGet]
    public IActionResult Get() {
        string path = pathProvider.MapPath("Sample.PNG");
        return View();
    }
}

Make sure to register the service with the DI container

services.AddSingleton<IPathProvider, PathProvider>();