MapStaticAssets, StaticWebAssetBasePath and multiple Blazor clients

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Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I have a Blazor Web application with 1 aspnetcore host and two blazor (webassembly) clients, all on .net9.0. I did not want to deal with hosting them on separate paths (through things like <base href=xx/> as it involved an existing application which would have been difficult to migrate, so they are exposed on separate domains.

To separate their assets I have been using "StaticWebAssetBasePath" in the csproj's to g et two folders in the wwwroot (say app-1 and app-2). So for the sake of discussion, i have app.com which gets (largely) served from wwwroot/app-1 and my.app.com which gets (largely) served from wwwroot/app-2. They are both able to use the same api which is accessible by route /api/xxx.

Some issues I had with this are that the server had to be modified slightly to point the applications to the correct paths for certain requests (mostly different PathBase)

• the _content directory is published in the wwwroot instead of wwwroot/app-1, requests to assets here seem to work with the PathBase changes on the server.
• resourcecollection.{fingerprint}.js and blazor.web.js do not exist on disk but generated by some middleware, it wont be served correctly unless the request pipeline has the correct PathBase set (app-1/app-2).
• _framework/dotnet.js will not be found with these PathBase changes on the server. I have to manually prepend the PathBase again to find the file like /app-1/app-1/_framework/dotnet.js.

So at this point I hack in a little middleware that essentially checks for any path some.file if {pathbase}/some.file exists on disk. Note that this does mean we are already looking for app-1/_framework/dotnet.js so we add the "missing" segment.

Now here we are, up and running. A bit wacky that is has to be like this but sure. However, I noticed that fingerprinting is now suffering from the same weird double PathBase requirement issue:

• Like with _framework/dotnet.js, I am already effectively serving /app-1/app-1/main.js. Even though the browser thinks its serving /main.js. To reiterate, I have to .UsePathBase in program.cs AND the middleware that adds the pathbase again, to the actual request path.
• The fingerprinded asset paths (resolved in App.razor through the ComponentBase.Assets property) do not work either unless the path base is included in the path /app-1/main.js.

In the last point, I would be adding the pathbase THREE times. Amazingly, this would in turn break the resolution of _framework.dotnet.js and my middleware hack (which I am not keen on keeping) cannot work around this by checking for a file on disk, because only the StaticAssetsEndpointDataSource which knows which file the path may map to.

So I have gotten a bit stuck here.

Expected Behavior

1. Static asset requests involving assets in a StaticAssetsBasePath directory need not add multiple PathBase's in the request uri to be resolved, wether they are fingerprinted or not.
2. Fingerprinting url resolution considers the StaticAssetsBasePath

Steps To Reproduce

Sample blazor web repo + add an extra client.

Serve each client from a separate 'sub application' using MapWhen(ctx => domain == x, app => configureApp(app). and configure each app with a separate PathBase and UseEndpoints with MapStaticAssets and MapRazorComponents/MapRazorPages.

Then set the StaticAssetsBasePath in each blazor client's csproj file, matching the respective pathbases ofcourse.

Exceptions (if any)

No response

.NET Version

9.0.203

Anything else?

No response