Fail: Microsoft.AspNetCore.SpaServices[0]

Question

Asp.net core 2.1 +Angular 6 application. In my Start.cs file. we have

app.UseSpa(spa =>
        {
            // To learn more about options for serving an Angular SPA from ASP.NET Core,
            // see https://go.microsoft.com/fwlink/?linkid=864501

            spa.Options.SourcePath = "ClientApp";

            if (env.IsDevelopment())
            {
                spa.UseAngularCliServer(npmScript: "start");
            }
        });

In the morning, I run the asp.net core application from Visual Studio(click F5). I got webpack build stuck on build module. It build a scss file for a long time and hangs there. So the web page throws asp.net core middleware exception.

However in the afternoon, I got a different error. Which is Fail: Microsoft.AspNetCore.SpaServices[0].

However if I run npm start in command window, then run dotnet run in Visual Studio code. It is fine.

Tell me what to do?

Answer 1

For ngcc lock file it is causing issue. Simply delete 'node_modules' folder in 'ClientApp' folder and re build the application.

Answer 2

I had a similar error as above (Fail: Microsoft.AspNetCore.SpaServices[0]) but for dotnet CLI (version 3.0.100, Angular 8.0). I simply created an Angular project - no error generated during build but when I ran it got the above error. After 10 minutes of investigation found the following issue during running angular server on it own:

This is because the path for the module HomeComponent was blank:

This code was autogenerated by dotnet tool so I am not sure why this was left out. The HomeComponent module is in Home folder. So adding the path solved the problem.

This may be useful for other newbies out there.