Document how to configure HttpClient base address in Blazor Server using IHttpClientFactory

[mihaimyh]

I am trying to configure HttpClient's base address in a Blazor Server using IHttpClientFactory but I am getting a runtime exception:

services.AddHttpClient("ApiClient", (provider, client) =>
{
    var uriHelper = provider.GetRequiredService<NavigationManager>();
    client.BaseAddress = new Uri(uriHelper.BaseUri);
});

Create an instance of this HttpClient using IHttpClientFactory and the following exception will be thrown:

_httpClient = httpClientFactory.CreateClient("ApiClient");

System.InvalidOperationException: 'Cannot resolve scoped service 'Microsoft.AspNetCore.Components.NavigationManager' from root provider.'

NET SDK (reflecting any global.json):
 Version:   5.0.100-preview.8.20417.9
 Commit:    fc62663a35

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.18363
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\5.0.100-preview.8.20417.9\

Host (useful for support):
  Version: 5.0.0-preview.8.20407.11
  Commit:  bf456654f9

.NET SDKs installed:
  3.1.401 [C:\Program Files\dotnet\sdk]
  5.0.100-preview.8.20417.9 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.0-preview.8.20414.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.0-preview.8.20407.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.0-preview.8.20411.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET runtimes or SDKs:
  https://aka.ms/dotnet-download

Anyone knows what might be the issue here?

[mihaimyh]

Tested it with both 3.1 and 5.0-preview8, same result.

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[mkArtakMSFT]

Thanks for contacting us.
We will investigate how this can be resolved in the future.

[aredfox]

Is there a workaround, or other solution meanwhile that can be promoted whilst it is in process of enhancement @SteveSandersonMS / @mkArtakMSFT? Thanks!

[arivera12]

I would just simply use the default http client factory services.AddHttpClient();

I did this kind of overriding the base http client address and it was a bad idea once when I started with blazor wasm and server.

I falled back to just include the HttpClient using it's default base root address where the web server is running.

What happens if you want to get a resource which is on the wwwroot of your blazor server/wasm application?

You will lose this main address in your http client...

If you are on native application then this would make sense at all to do it.

I would suggest to change approach and make a HttpClientService per specific API controllers instead and inside set up you base http client address.

I know this doesn't answer the asked question but it's my experience based on this when I did this approach before this should not be done at all.

I even think it should be considered a bad practice at all.

[agilenut]

I would also like to see this addressed. I need to be able to add a user's access token to a named HTTP client. But I'm getting the same exception when I try to resolve the AuthenticationStateProvider to figure who the user is. This should be a supported scenario.