blazor.web.js is 404 when Blazor project runs as part of Aspire

[petrroll]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When trying to contribute to Wiremock.net I've noticed when the web-project that's part of their Aspire examples is run within the context of Aspire, blazor fails due to requests for blazor.web.js failing with 404 (from kestrel). When the project is run standalone it all works fine.

Expected Behavior

Blazor should work.

Steps To Reproduce

1. Clone https://github.com/petrroll/WireMock.Net/tree/petrhouska/update-aspire
2. Run (using aspire cli) aspire run ./examples-Aspire/AspireApp1.AppHost/AspireApp1.AppHost.csproj
3. Open the webfrontend portal
4. Observe 404 error for blazor.web.js (and generally broken blazor experience on /weather

Weirdly enough, if you run the webfrontend project separately, it all works fine.

Exceptions (if any)

GET https://localhost:7263/_framework/blazor.web.js net::ERR_ABORTED 404 (Not Found)
Responder is Kestrel, so there's no caching shenanigans

.NET Version

10.0.101

Anything else?

aspire --version
13.1.0+8a4db1775c3fbae1c602022b636299cb04971fde

[petrroll]

I tried to follow #64451 but it didn't help me much.

[petrroll]

This is binlog for build of the project separately:

AspireApp1.Web.zip

[petrroll]

It works when run via Aspire from VS. Only when run via Aspire CLI causes the issue.

[javiercn]

@petrroll thanks for contacting us.

Is the app targeting .net 8.0 but running on the .net 10.0 runtime?

[petrroll]

Yep but that should not play a role. I also tried with it targeting net90 (with most of nugget deps of version 10). Same thing.

[petrroll]

Various combinations of map static files Claude came up with also fell short.