How to retrieve current application root URL in .net core within a static method?

Question

I am currently using the Request.Scheme and Request.Host to composite Uri object to get AbsoluteUri for my .net core MVC application.

Uri location = new Uri($"{Request.Scheme}://{Request.Host}");
string applicationRootURL = location.AbsoluteUri;

But this only works in a non-static method.

As I need to re-use this method in another controller, I am thinking to make this action method static. If I do that, the compiler will complaint about the Request.Scheme and Request.Host.

I am wondering what's other options I have to achieve this?

Thank you.

UPDATE:

This is what I have for ControllerA with ActionMethodA

public class ControllerA
{
    public bool ActionMethodA()
    {
        Uri location = new Uri($"{Request.Scheme}://{Request.Host}");
        string applicationRootURL = location.AbsoluteUri;

        return false;
    }
}

And in another ControllerB, I want to ActionMethodB to invoke ActionMethodA from ControllerA:

public class ControllerB
{
    public void ActionMethodB()
    {
        var result = ActionMethodA();
    }
}

Is creating an Extension Method to the ControllerA is the most proper way to handle this kind of scenario?

Thank you.

Sorry, didn't figure out how. But plan to implement the solution without making the method static. — Xiao Han, Apr 11 '18 at 21:07
It's one of the most basic and most commonly used features in C# https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/extension-methods — Tseng, Apr 11 '18 at 21:08

score 1 · Answer 1 · answered Apr 12 '18 at 10:33

1

You can also define an extension method directly for the HttpRequest class and use the BuildAbsolute method of the UriHelper class to build the uri.

public static class HttpRequestExtensions
{
    public static string GetURI(this HttpRequest request)
    {
        return UriHelper.BuildAbsolute(request.Scheme, request.Host);
    }
}

And use it:

public IActionResult ContollerMethod()
{
    var uri = Request.GetURI();

    // your code
}

answered Apr 12 '18 at 10:33

Andriy Tolstoy

5,690
2
31
30

Thanks. What I want is making the ControllerMethod to be static, so in another Controller, I can invoke this ControllerMethod like var result = ControllerMethod(); directly. Is it possible? – Xiao Han Apr 13 '18 at 17:04
@XiaoHan There is not an instance reference to a request object in a static method. So I do not think it is possible. – Andriy Tolstoy Apr 16 '18 at 09:29
Thank you. Is there any other way I can get application URL within a static method? – Xiao Han Apr 16 '18 at 14:09
@XiaoHan Within a parameterless static method? I do not think there is any other way to accomplish it. – Andriy Tolstoy Apr 17 '18 at 07:03
Not necessarily, can pass any parameter. – Xiao Han Apr 17 '18 at 18:15
@XiaoHan So basically it is certainly possible to define a static method like this one ```public static bool ActionMethodA(HttpRequest request)``` and call it from an another controller with an appropriate request parameter. But even though it works, it is not a right solution, because one controller should not be responsible for a request of another one. – Andriy Tolstoy Apr 18 '18 at 08:06
I can isolate this static method into a helper/util class to be able to shared and invoked by multiple controller. But not sure if the URL information can be retrieved within this static method. – Xiao Han Apr 18 '18 at 17:48
@XiaoHan Yes, it is also an option. You can get the URL information the same way using ```HttpRequest``` object as a parameter of the static method. Further helpful reading: https://stackoverflow.com/questions/4646328/extension-methods-vs-static-utility-class – Andriy Tolstoy Apr 19 '18 at 07:18

score -1 · Answer 2 · answered Apr 12 '18 at 08:30

You can write an extension method to a controller or HttpContext object. In the following example I have added an extension method to the controller.

 public static class ControllerExtensions
{
    public static string GetURI(this Controller controller)
    {
        Uri location = new Uri($"{ controller.Request.Scheme}://{controller.Request.Host}");
        string applicationRootURL = location.AbsoluteUri;
        return applicationRootURL;
    }
}

Once the extension method is written you can call it in the following manner.

public IActionResult Index()
    {
        var url = this.GetURI();
        return View();
    }

Make sure to import namespace of an extension method in your calling code

If I want to make Index() static, is it still working? – Xiao Han Apr 13 '18 at 20:08 — Xiao Han, Apr 13 '18 at 20:08

How to retrieve current application root URL in .net core within a static method?

2 Answers2