ASP.NET Core 3.0 HttpContext.Current.Server.MapPath

Question

Im migration a classic C# MVC project to .NET Core and I have a Utility Project where I need to get access of App_Data folder.

I already create in this new project my App_Data folder outside wwwroot but I need to get reference to it from this Utility Project.

This is my old code:

 public static class Common
    {
      private static void DeleteTestFiles()
            {
                var path = HttpContext.Current.Server.MapPath("~/App_Data/Files");
                .....
    }
}

I was reading that in 3.0 there is a way to do this, here the example:

 private readonly IWebHostEnvironment _hostingEnvironment;

        public HomeController(IWebHostEnvironment hostingEnvironment)
        {
            _hostingEnvironment = hostingEnvironment;
        }

        public ActionResult Index()
        {
            string webRootPath = _hostingEnvironment.WebRootPath;
            string contentRootPath = _hostingEnvironment.ContentRootPath;

            return Content(webRootPath + "\n" + contentRootPath);
        }

But above code is for a Controller that lives in the web project. My Utility Projects common class is not a Controller and is a static class so I cannot have constructor in order to have IWebHostEnvironment to be injected automaticly.

Any clue how can I do get the path or maybe I need to manually inject IWebHostEnvironment but don't have a clue.

Answer 1

Don't use a static class. You can keep something similar to your class, and register it as a singleton.

public class Common
{
    private readonly IWebHostEnvironment _env;

    public Common(IWebHostEnvironment env)
    {
        _env = env;
    }

    private void DeleteTestFiles()
    {
            var path = Path.Combine(_env.ContentRootPath, "App_Data/Files");
            .....
    }
}

Then, in Startup.ConfigureServices:

services.AddSingleton<Common>();

Finally, inject Common where you need it, instead of just statically referencing the class. This is how things work in DI, statics are a no-go.

UPDATE:

In order this to work, because the Utility project is referencing Microsoft.NETCore.App and not Microsoft.AspNetCore.App framework then you have to use IHostEnvironment instead of IWebHostEnvironment.

IWebHostEnvironment actually implements IHostEnvironment interface.

Did the test and all working good! I could get the ContentRootPath.

public class Common
    {
        private readonly IHostEnvironment _env;

        public Common(IHostEnvironment env)
        {
            _env = env;
        }

        private void DeleteTestFiles()
        {
                var path = Path.Combine(_env.ContentRootPath, "App_Data/Files");
                .....
        }
    }

Answer 2

.Net 6 (.NetCore 3 and above) For example I want to locate ~/wwwroot/CSS

public class YourController : Controller
{
    private readonly IWebHostEnvironment _webHostEnvironment;

    public YourController (IWebHostEnvironment webHostEnvironment)
    {
        _webHostEnvironment= webHostEnvironment;
    }

    public IActionResult Index()
    {
        string webRootPath = _webHostEnvironment.WebRootPath;
        string contentRootPath = _webHostEnvironment.ContentRootPath;

        string path ="";
        path = Path.Combine(webRootPath , "CSS");
        //or path = Path.Combine(contentRootPath , "wwwroot" ,"CSS" );
        return View();
    }
}