How to Get the Base Url of a Server-Side Blazor App

Question

I have a server-side blazor app and I need to know it's base url (e.g. https://localhost:1234 or https://my-host.com/appname).

In a traditional ASP.NET web application, I could inspect the Request property of a controller and retrieve the information from it (there's Scheme, Host, and PathBase for that). But since this is a server-side running Blazor app, there is no Request object (at least in my understanding and except maybe when serving the Index.cshtml).

How can I then know, to which URL my app has been deployed to and is running at?

Ideally, I would already have this information at startup time, so that I can configure my services accordingly.

Midwest

Answer 1

Getting it inside a page is easy:

@inject NavigationManager Navigator

<p>@Navigator.BaseUri</p>

But you can't use a NavigationManager in the Startup class.

Shroudlaid

That already helps a lot. I can build a work-around with this until somebody figures out how to get this at startup. – Midwest

If there is a NuGet pkg required for this it would be nice if this information is always included with answers. It cannot be assumed that we would know. – Silvers

I thumbed this up even in Oct 2020 because it lead me to the right direction but for those coming here now for .NET 5 have a look at the NavigationManager. – Doorman

So, is it safe to say that there is no practical way to get the base URL in the Program.cs file where there is var builder = WebApplication.CreateBuilder(args); in a Blazor Server-side project? ---- Because, I saw a sample project of Blazor WebAssembly project, where the author used var builder = WebAssemblyHostBuilder.CreateDefault(args); builder.HostEnvironment.BaseAddress in the Program.cs of the Client project. – Oshea

@DamnVegetables - this is an old answer but mostly it is for Blazor-Server. No HostEnvironhment there. – Shroudlaid

Answer 2

In .Net Core 3.0 onwards IUriHelper has been replaced by NavigationManager

To use inside a Blazor page:

    @inject NavigationManager NavigationManager

   //example usage
   var client = _clientFactory.CreateClient();
   client.BaseAddress = new Uri(NavigationManager.BaseUri);

Scapular

Answer 3

@Navigator.BaseUri is not always working.

let's say your URL is something like the below :
https://localhost:7113/?ak=aoe4BFL/ then the @Navigator.BaseUri returns the whole string:

?NavigationManager.BaseUri
"https://localhost:7113/?ak=aoe4BFL/"
?NavigationManager.Uri
"https://localhost:7113/?ak=aoe4BFL/"

Porcine