.Net5.0 not respecting StaticWebAssetBasePath on publish of Blazor WASM project

[chris03]

Describe the bug

After upgrading to .Net5.0 I noticed that when publishing (dotnet publish) a Blazor WASM project the StaticWebAssetBasePath is not taken into account.
The files inside wwwroot are not put in the specified base folder.
However, when the project is run, the framework files are correctly located.

I'm following this documentation about <StaticWebAssetBasePath>
https://docs.microsoft.com/en-us/aspnet/core/blazor/host-and-deploy/webassembly?view=aspnetcore-5.0#hosted-deployment-with-multiple-blazor-webassembly-apps

To Reproduce

Run: dotnet new blazorwasm
Open the .csproj file
Add <StaticWebAssetBasePath>test</StaticWebAssetBasePath> inside <PropertyGroup>
Save & Run: dotnet publish
Look at the content of: bin\Debug\net5.0\publish\wwwroot

Current result: Most files are incorrectly located in wwwroot and some files are inside wwwroot\test
Expected result: All files (framework,css,...) should be inside wwwroot\test

I get the expected result when running the same steps with .NetCore 3.1 (dotnet new blazorwasm -f netcoreapp3.1)

Further technical details

• .Net 5.0

dotnet --info
.NET SDK (reflecting any global.json):
 Version:   5.0.100
 Commit:    5044b93829

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19041
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\5.0.100\

Host (useful for support):
  Version: 5.0.0
  Commit:  cf258a14b7

.NET SDKs installed:
  5.0.100 [C:\Program Files\dotnet\sdk]

I ran the commands on the command line.

[javiercn]

@chris03 thanks for the details.

@pranavkm this seems like a bug, but we do have tests for this, so I'm a bit confused. Can it be that we don't have a test that changes the static web asset base path?

[mvromer]

I'm seeing this as well. In my case I set <StaticWebAssetBasePath>static</StaticWebAssetBasePath> in my csproj file.

After setting a custom StaticWebAssetBasePath property, I'm also seeing the Blazor app fail to load when running dotnet run. In my case, this is what I tried:

1. Run dotnet new blazorwasm -o ExampleClassifierApp
2. Update ExampleClassifierApp.csproj with the new StaticWebAssetBasePath above.
3. Modify index.html and FetchData.razor so that paths to the static assets (CSS, JS, and JSON files) they request are prefixed with static/.

After starting dotnet run and going to https://localhost:5001, the app fails to load with the following errors in my dev tools:

For grins I created a wwwroot/static folder inside my project's root directory and moved the static css and sample-data folders into that. Rerunning that shows that the static CSS loads now, but the blazor.boot.json can't be loaded:

Looks like blazor.webassembly.js tries to fetch _framework/blazor.boot.json, which will be relative to where the index is being served from (the root in this case) and not relative to the path set for StaticWebAssetBasePath.

[alexchiraples]

I'm seeing this as well.

Context:

1. Blazor WebAssembly App, PWA, Core hosted, auth w/ Individual user accounts, created with 3.1 (app1)
2. Upgraded app1.Client, app1.Server and app1.Shared to net 5
3. Create a second app (app2) hosted, and configure it to connect to app1 server
4. Configure app1 and app2 as Hosted deployment with multiple Blazor WebAssembly apps as documented https://docs.microsoft.com/en-us/aspnet/core/blazor/host-and-deploy/webassembly?view=aspnetcore-5.0#hosted-deployment-with-multiple-blazor-webassembly-apps

Goal:
Hosted deployment with multiple Blazor WebAssembly apps

• /app1
• /app2

After following the docs and receiving lots of errors, including those described in this issue, I've managed to bypass most of them. I'm stuck at a 401 error when calling the APIs even if the user is authenticated. For example: oidc.user:https://localhost:44352:app1 and app2 have all the required values. I am not sure if this this is related to the StaticWebAssetBasePath thing or if it should be another issue opened on this topic.

Please find below sample of my configuration for achieving:

• hosted deployments
• multiple blazor webassembly apps
• different base path
• authentication (Identity)

dotnet version

λ dotnet --info
.NET SDK (reflecting any global.json):
 Version:   5.0.100
 Commit:    5044b93829

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\

Host (useful for support):
  Version: 5.0.0
  Commit:  cf258a14b7

.NET SDKs installed:
  3.1.402 [C:\Program Files\dotnet\sdk]
  5.0.100 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Server/Startup.cs

app.UseBlazorFrameworkFiles("/app1");
app.UseBlazorFrameworkFiles("/app2");
app.UseStaticFiles();

app.UseRouting();

app.UseIdentityServer();
app.UseAuthentication();
app.UseAuthorization();


app.UseEndpoints(endpoints =>
{
	endpoints.MapRazorPages();
	endpoints.MapControllers();

	endpoints.MapFallbackToFile("/app1/index.html");
	endpoints.MapFallbackToFile("/app1/{*path:nonfile}", "app1/index.html");
	endpoints.MapFallbackToFile("/app2/{*path:nonfile}", "app2/index.html");

	
	// default path to app1
	endpoints.MapGet("/", context => Task.Factory.StartNew(() => context.Response.Redirect("/app1", true, true)));

	endpoints.MapGet("/app1/_configuration/app1.Client", context => Task.Factory.StartNew(() => context.Response.Redirect("/_configuration/app1.Client", true, true)));
	endpoints.MapGet("/app2/_configuration/app2.Client", context => Task.Factory.StartNew(() => context.Response.Redirect("/_configuration/app2.Client", true, true)));

});

Server/application.json

"IdentityServer": {
        "Clients": {
            "app1.Client": {
                "Profile": "IdentityServerSPA",
                "RedirectUri": "/app1/authentication/login-callback",
                "LogoutUri": "/app1/authentication/logout-callback"
            },
            "app2.Client": {
                "Profile": "IdentityServerSPA",
                "RedirectUri": "/app2/authentication/login-callback",
                "LogoutUri": "/app2/authentication/logout-callback"
            }
        },
        "Key": {
            "Type": "Development"
        }
    }

app1/wwwroot/index.html (similar configuration for app2)

<head>
  ...
  <base href="/app1/" />
  ...
</head>
<body>
  ...
  <script src="/_content/Microsoft.AspNetCore.Components.WebAssembly.Authentication/AuthenticationService.js"></script>
  <script src="_framework/blazor.webassembly.js"></script>
  ...
</body>

app1/Program.cs

 var builder = WebAssemblyHostBuilder.CreateDefault(args);
builder.RootComponents.Add<App>("#app");


builder.Services.AddHttpClient("app1.ServerAPI", client => client.BaseAddress = new Uri(builder.HostEnvironment.BaseAddress))
                .AddHttpMessageHandler<BaseAddressAuthorizationMessageHandler>();

// Supply HttpClient instances that include access tokens when making requests to the server project
builder.Services.AddScoped(sp => sp.GetRequiredService<IHttpClientFactory>().CreateClient("app1.ServerAPI"));

builder.Services.AddApiAuthorization();

await builder.Build().RunAsync();

After doing all of this, everything works except calling any API that requires authorization. #19928 looks similar.