How to get base URL in Web API controller?

I know that I can use Url.Link() to get URL of a specific route, but how can I get Web API base URL in Web API controller?

In the action method of the request to the url "http://localhost:85458/api/ctrl/"

var baseUrl = Request.RequestUri.GetLeftPart(UriPartial.Authority) ;

this will get you http://localhost:85458

Url.Content("~/")

worked for me!

You could use VirtualPathRoot property from HttpRequestContext (request.GetRequestContext().VirtualPathRoot)

This is what I use:

Uri baseUri = new Uri(Request.RequestUri.AbsoluteUri.Replace(Request.RequestUri.PathAndQuery, String.Empty));

Then when I combine it with another relative path, I use the following:

string resourceRelative = "~/images/myImage.jpg";
Uri resourceFullPath = new Uri(baseUri, VirtualPathUtility.ToAbsolute(resourceRelative));

In .NET Core WebAPI (version 3.0 and above):

var requestUrl = $"{Request.Scheme}://{Request.Host.Value}/";


     

I inject this service into my controllers.

 public class LinkFactory : ILinkFactory
 {
    private readonly HttpRequestMessage _requestMessage;
    private readonly string _virtualPathRoot;


    public LinkFactory(HttpRequestMessage requestMessage)
    {
        _requestMessage = requestMessage;
        var configuration = _requestMessage.Properties[HttpPropertyKeys.HttpConfigurationKey] as HttpConfiguration;
        _virtualPathRoot = configuration.VirtualPathRoot;
        if (!_virtualPathRoot.EndsWith("/"))
        {
            _virtualPathRoot += "/";
        }
    }

    public Uri ResolveApplicationUri(Uri relativeUri)
    {
        
        return new Uri(new Uri(new Uri(_requestMessage.RequestUri.GetLeftPart(UriPartial.Authority)), _virtualPathRoot), relativeUri);
    }

}

Use the following snippet from the Url helper class

Url.Link("DefaultApi", new { controller = "Person", id = person.Id })

The full article is available here: http://blogs.msdn.com/b/roncain/archive/2012/07/17/using-the-asp-net-web-api-urlhelper.aspx

This is the official way which does not require any helper or workaround. If you look at this approach is like ASP.NET MVC

new Uri(Request.RequestUri, RequestContext.VirtualPathRoot)

In ASP.NET Core ApiController the Request property is only the message. But there is still Context.Request where you can get expected info. Personally I use this extension method:

public static string GetBaseUrl(this HttpRequest request)
{
    // SSL offloading
    var scheme = request.Host.Host.Contains("localhost") ? request.Scheme : "https";
    return $"{scheme}://{request.Host}{request.PathBase}";
}

Not sure if this is a Web API 2 addition, but RequestContext has a Url property which is a UrlHelper: HttpRequestContext Properties. It has Link and Content methods. Details here

First you get full URL using HttpContext.Current.Request.Url.ToString(); then replace your method url using Replace("user/login", "").

Full code will be

string host = HttpContext.Current.Request.Url.ToString().Replace("user/login", "")

Base on Athadu's answer, I write an extenesion method, then in the Controller Class you can get root url by this.RootUrl();

public static class ControllerHelper
{
    public static string RootUrl(this ApiController controller)
    {
        return controller.Url.Content("~/");
    }
}

send a GET to a page and the content replied will be the answer.Base url : http://website/api/

1. Add a reference to System.Web using System.Web;

2. Get the host or any other component of the url you want string host = HttpContext.Current.Request.Url.Host;

From HttpRequestMessage

request.Headers.Host

Al WebApi 2, just calling HttpContext.Current.Request.Path;