63

I have this line in some code I want to copy into my controller, but the compiler complains that

The name 'Server' does not exist in the current context

var UploadPath = Server.MapPath("~/App_Data/uploads")

How can I achieve the equivalent in ASP.NET Core?

ProfK
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    Use `IHostingEnvironment.WebRootPath` and then use `Path.Combine` with second argument assigned to target directory. See [Server.MapPath Equivalent in ASP.NET Core](https://www.mikesdotnetting.com/article/302/server-mappath-equivalent-in-asp-net-core) for further reference. – Tetsuya Yamamoto Mar 21 '18 at 05:46

4 Answers4

69

UPDATE: IHostingEnvironment is deprecated. See update below.

In Asp.NET Core 2.2 and below, the hosting environment has been abstracted using the interface, IHostingEnvironment

The ContentRootPath property will give you access to the absolute path to the application content files.

You may also use the property, WebRootPath if you would like to access the web-servable root path (www folder by default)

You may inject this dependency into your controller and access it as follows:

public class HomeController : Controller
    {
        private readonly IHostingEnvironment _hostingEnvironment;

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

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

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

UPDATE - .NET CORE 3.0 and Above

IHostingEnvironment has been marked obsolete with .NET Core 3.0 as pointed out by @amir133. You should be using IWebHostEnvironment instead of IHostingEnvironment. Please refer to that answer below.

Microsoft has neatly segregated the host environment properties among these interfaces. Please refer to the interface definition below:

namespace Microsoft.Extensions.Hosting
{
  public interface IHostEnvironment
  {
    string EnvironmentName { get; set; }
    string ApplicationName { get; set; }
    string ContentRootPath { get; set; }
    IFileProvider ContentRootFileProvider { get; set; }
  }
}

namespace Microsoft.AspNetCore.Hosting
{
  public interface IWebHostEnvironment : IHostEnvironment
  {
    string WebRootPath { get; set; }
    IFileProvider WebRootFileProvider { get; set; }
  }
}
ashin
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  • I edited this so you're not copying @aamir133's answer. – Mukus Mar 10 '20 at 23:21
  • Thanks..In fact, i didn't copy aamir's code, I copied my initial answer and replaced the interface. :) But what you said makes sense, I have edited again and just linked the answer to aamir's and also provided the interface definition for people who are interested to know how the properties are laid out among those interfaces.. – ashin Mar 12 '20 at 05:15
  • It's not clear what the actual answer to the OP is?! – niico Jan 25 '21 at 03:26
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    I hate dependency injection. How can I get the hosting environment without using DI? – A X Feb 27 '21 at 07:45
  • Just ran into this while trying to freshen up a site to have new content. Why was this done? It certainly seems less intuitive to me. In fact, gone seem to be the days when Microsoft made development fun. Now code all seems to look like some kind of hack job by new generation kids who don't want to write all of the code down. – jp2code Apr 07 '21 at 17:09
43

.Net 5 ,.net core 3

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();
    }
}

Some Tricks

Also if you don't have a controller or service,follow last Part and register it's class as a singleton. Then, in Startup.ConfigureServices:

services.AddSingleton<your_class_Name>();

Finally, inject your_class_Name where you need it.


.Net Core 2

For example I want to locate ~/wwwroot/CSS

public class YourController : Controller
{
    private readonly IHostingEnvironment _HostEnvironment;

    public YourController (IHostingEnvironment HostEnvironment)
    {
        _HostEnvironment= HostEnvironment;
    }

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

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

MoreDetails

Thanks to @Ashin but IHostingEnvironment is obsoleted in MVC core 3!!

according to this :

Obsolete types (warning):

Microsoft.Extensions.Hosting.IHostingEnvironment
Microsoft.AspNetCore.Hosting.IHostingEnvironment
Microsoft.Extensions.Hosting.IApplicationLifetime
Microsoft.AspNetCore.Hosting.IApplicationLifetime
Microsoft.Extensions.Hosting.EnvironmentName
Microsoft.AspNetCore.Hosting.EnvironmentName

New types:

Microsoft.Extensions.Hosting.IHostEnvironment
Microsoft.AspNetCore.Hosting.IWebHostEnvironment : IHostEnvironment
Microsoft.Extensions.Hosting.IHostApplicationLifetime
Microsoft.Extensions.Hosting.Environments 

So you must use IWebHostEnvironment instead of IHostingEnvironment.

Amir133
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    Thanks amir133 for pointing it out..i have updated the answer – ashin May 07 '19 at 05:43
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    @ashin You updated the answer to write exactly what amir133 wrote. Why not just mention refer to amir133's answer instead? – Mukus Mar 10 '20 at 23:18
14

The accepted answer's suggestion is good enough in most scenarios, however - since it depends on Dependency Injection - is limited to Controllers and Views: in order to have a proper Server.MapPath replacement that can be accessed from non-singleton helper classes we can add the following line(s) of code at the end of the Configure() method of the app's Startup.cs file:

// setup app's root folders
AppDomain.CurrentDomain.SetData("ContentRootPath", env.ContentRootPath);
AppDomain.CurrentDomain.SetData("WebRootPath", env.WebRootPath);

This way we'll be able to retrieve them from within any class (including, yet not limiting to, Controllers and Views) in the following way:

var contentRootPath = (string)AppDomain.CurrentDomain.GetData("ContentRootPath");
var webRootPath = (string)AppDomain.CurrentDomain.GetData("WebRootPath");

This can be further exploited to create a static helper method that will allow us to have the same functionality as the good old Server.MapPath:

public static class MyServer 
{
    public static string MapPath(string path)
    {
        return Path.Combine(
            (string)AppDomain.CurrentDomain.GetData("ContentRootPath"), 
            path);
    }
}

Which can be used it in the following way:

var docPath = MyServer.MapPath("App_Data/docs");

For additional info regarding this approach and a bit of background, take a look at this post on my blog.

Andrew Schultz
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Darkseal
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1

use for example: var fullPath = Path.Combine(Directory.GetCurrentDirectory(), "appsettings.json");

German Gracia
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