These changes allow Aspire service discovery to work in a hosted Blaz…

[BenjaminCharlton]

These changes allow Aspire service discovery to work with a hosted Blazor WebAssembly app.

It basically integrates my Nuget package Aspire4Wasm (source code here) into Aspire (with the addition of only 5 new classes and 2 interfaces, and changing none of the existing ones).

The changes allow an Aspire AppHost to define web APIs that a Blazor app can access, and pass that service discovery information to the app by writing to its appsettings.{environment}.json files.

These changes will not make the Aspire developer experience with Blazor totally seamless. For example, I'm still having difficulty with stand-alone Blazor WebAssembly apps, and I haven't figured out how to stop the app launching on a random port as well as the one specified in launchsettings.json. However, this is a step in the right direction and will help make Aspire a bit more Blazor-friendly. If you want to see what it does before accepting the changes, try the Nuget package Aspire4Wasm (version 3.0.0 at the time of writing).

Description

Please include a summary of the changes and the related issue. Please also include relevant motivation and context. List any dependencies that are required for this change.

Fixes # (issue)

Checklist

• Is this feature complete?
  • [ x ] Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • [ x ] Yes
  • No
• Did you add public API?
  • [ x ] Yes
    • If yes, did you have an API Review for it?
      • Yes
      • [ x ] No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • [ x ] Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • [ x ] No
• Does the change require an update in our Aspire docs?
  • Yes
    • Is this introducing a breaking change?
      • Yes
        • Link to aspire-docs issue (please use this breaking-change template):
      • [ x ] No
        • Link to aspire-docs issue (please use this doc-idea template):
  • [ x ] No (The triple slash/XML remarks should be sufficient documentation but I'm happy to add more if needed.

[davidfowl]

A change this big should be an issue with an API proposal and a design. That will dramatically increase the changes of it getting reviewed and aligned with a release.

[BenjaminCharlton]

Hi @davidfowl ! Thanks for your interest. I'm happy for you to guide me through that if that's what I need to do. It's my first time contributing to Aspire.

I saw a lot of issues already about getting Aspire to play nicely with Blazor (server, webassembly, hosted and standalone), or tangentially related to using Aspire with front end GUIs. People seem to agree that it has loads of potential! I wasn't sure another issue would be appreciated. Should we use an existing one?

I thought maybe, out of these open issues, the fourth one is pretty much exactly what my PR is about:

• Aspire launches the client of a hosted Blazor WebAssembly app on a different random port every time the AppHost is launched
• .NET Aspire: Scalar displays API instance url when accessing via proxy
• Server URLs in OpenAPI document are incorrect when application used with .NET Aspire
• Is there any way to use ServiceDiscovery for client (aka browser) apps?
• Aspire project with Blazor WASM/server project opens by itself
• Unable to deploy Blazor wasm project to Aspire

Shall we use that rather than open a fresh one? Do you have a template for an API proposal and design I can follow please?

[JJong-nl]

The a code example for setting the opening browser to a fixed port.

A TargetPort cannot be set from the launchSettings.
So after the launchSettings are retreived, change the endpoints TargetPort

#3145 (comment)