Builder.WebHost.UseUrls does not seem to override default url

[Buildstarted]

Previously mentioned: #36245

Describe the bug

Builder.WebHost.UseUrls() fails to use the port/url provided

To Reproduce

var builder = WebApplication.CreateBuilder(args);
builder.WebHost.UseUrls("http://*:8080");
var app = builder.Build();
app.Run();

Further technical details

• ASP.NET Core version: 6.0
• The IDE (VS / VS Code/ VS4Mac) you're running on, and its version: VS
• Include the output of dotnet --info:

dotnet --info Output

Host (useful for support):
  Version: 6.0.0
  Commit:  4822e3c3aa

.NET SDKs installed:
  5.0.100 [C:\Program Files\dotnet\sdk]
  5.0.104 [C:\Program Files\dotnet\sdk]
  5.0.208 [C:\Program Files\dotnet\sdk]
  5.0.303 [C:\Program Files\dotnet\sdk]
  5.0.402 [C:\Program Files\dotnet\sdk]
  6.0.100-rc.1.21460.8 [C:\Program Files\dotnet\sdk]
  6.0.100 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.0-rc.1.21452.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0-rc.1.21451.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.0-rc.1.21451.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

[Tratcher]

@halter73

[halter73]

This is a bug.

Certain IWebHostBuilder extension methods are unsupported and throw when they're called (e.g. builder.WebHost.UseEnvironment("{EnvironmentName}")) because it's too late to reload all the config at this point. However, we have WebApplicationOptions which can be passed to CreateBuilder(WebApplicationOptions options) to make up for that.

Server urls are bound late enough that this should work as is. Unfortunately there's a bug where stale hosting config is incorrectly overriding the urls configured with UseUrls(params string[] urls). This is what Configuration looks like on this line.

There are a number of workarounds depending on your requirements. The easiest is likely passing in the url argument to WebApplication.Run(string? url = null).

app.Run("http://*:8080");

[davidfowl]

I think we should also patch this in 6.0.x

[halter73]

I agree it should be patched. I almost milestoned it myself, but figured we could discuss in triage.

[tehmufifnman]

Oof... so glad I came across this! I spent a whole day trying to figure out why my service wasn't working in my container and this was 100% it haha!

[tetious]

For me, trying to override the URL in Run results in the following Changing the URL is not supported because no valid IServerAddressesFeature was found. when using WebApplicationFactory for testing. I'm uncertain if this is a mistake in my configuration/usage or a separate bug...

Setting ENV ASPNETCORE_URLS=http://+:5050 within the runtime image section in our Dockerfile worked, however, and doesn't break testing.

[tehmufifnman]

For me, trying to override the URL in Run results in the following Changing the URL is not supported because no valid IServerAddressesFeature was found. when using WebApplicationFactory for testing. I'm uncertain if this is a mistake in my configuration/usage or a separate bug...

Setting ENV ASPNETCORE_URLS=http://+:5050 within the runtime image section in our Dockerfile worked, however, and doesn't break testing.

Do you have a code snippet to share?

[OronDF343]

This issue also affects setting the Urls property in appsettings.{env}.json. This breaks a lot of our ASP.NET Core 3.1 projects when run in a development environment since they won't be accessible on the LAN (for some reason, launchsettings.json does not support listening on all IPs, only a specific one or localhost).

Works in 3.1 (listens on http://[::]:4321), does not work in 6.0 (listens on http://localhost:4321):

{
    "Urls": "http://*:4321"
}

Workaround for 6.0 (listens on http://[::]:4321):

{
  "Kestrel": {
    "Endpoints": {
      "Http": {
        "Url": "http://*:4321"
      }
    }
  }
}