dotnet build - get error "could not return the default page '/index.html'"

Question

try to generate my project into exe file, but get error:

before: "dotnet build -r win10-x86" is ok

after run generated exe, all is ok also:

indows DPAPI to encrypt keys at rest.
Hosting environment: Production
Content root path: C:....\currencyColution\correncyProject\bin\Debug\netcoreapp2.1\win10-x86
Now listening on: http://localhost:5000
Now listening on: https://localhost:5001
Application started. Press Ctrl+C to shut down.

after load page is somwthing worng, more precisely index.html is not found:

info: Microsoft.AspNetCore.Hosting.Internal.WebHost[1]
      Request starting HTTP/1.1 GET http://localhost:5000/
fail: Microsoft.AspNetCore.Server.Kestrel[13]
      Connection id "0HLG91TC2H0UO", Request id "0HLG91TC2H0UO:00000001": An 

unhandled exception was thrown by the application.
System.InvalidOperationException: The SPA default page middleware could not return the default page '/index.html' because it was not found, and no other middleware handled the request.
Your application is running in Production mode, so make sure it has been published, or that you have built your SPA manually. Alternatively you may wish to switch to the Development environment.

Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.SpaServices.AngularCli;
using Microsoft.Extensions.DependencyInjection;
using Swashbuckle.AspNetCore.Swagger;
using System;
using System.IO;
using Microsoft.AspNetCore.Http;

namespace AspNetCore2Ang6Template
{
  public class Startup
  {
  
    public void ConfigureServices(IServiceCollection services)
    {
      services.AddMvc();
      services.AddSpaStaticFiles(c =>
      {
        c.RootPath = "wwwroot";
      });

    }

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
      if (env.IsDevelopment())
      {
        app.UseDeveloperExceptionPage();
      }

      app.UseDefaultFiles();
      app.UseStaticFiles();
      app.UseSpaStaticFiles();
      app.UseMvc(routes =>
      {
        routes.MapRoute(name: "default", template: "{controller}/{action=index}/{id}");
      });

      app.UseSpa(spa =>
      {
        spa.Options.SourcePath = "wwwroot";
      });

    }
  }
}

I dont't use angular and some other ones, just try to open wwwroot/index.html

files:

currencyProject

wwwroot

Program.cs

Startup.cs

Tested in VS , all works, but not via exe builder

launched like dev : dotnet run, then it works on localhost:58893/, but what is wrong with prod dotnet build on localhost:5000

launchSettings:

{
  "iisSettings": {
    "windowsAuthentication": false,
    "anonymousAuthentication": true,
    "iisExpress": {
      "applicationUrl": "http://localhost:58842/",
      "sslPort": 0
    }
  },
  "profiles": {
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    },
    "AspNetCore2Ang6Template": {
      "commandName": "Project",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      },
      "applicationUrl": "http://localhost:58893/"
    }
  }
}

Answer 1

Resolved this issue by comparing existing Angular Asp net core template, I did following code changes.

In csproj file:

<TypeScriptCompileBlocked>true</TypeScriptCompileBlocked>
 <TypeScriptToolsVersion>Latest</TypeScriptToolsVersion>
 <IsPackable>false</IsPackable>
 <SpaRoot>ClientApp\</SpaRoot>
 <DefaultItemExcludes>$(DefaultItemExcludes);$(SpaRoot)node_modules\**</DefaultItemExcludes>

 <!-- Set this to true if you enable server-side prerendering -->
 <BuildServerSideRenderer>false</BuildServerSideRenderer>
 <UserSecretsId>baa2f579-d2a7-4eb4-89fb-1c171b2e2482</UserSecretsId>
 <TypeScriptToolsVersion>3.0</TypeScriptToolsVersion>

<ItemGroup>
 <TypeScriptCompile Include="App\src\app\models\user.ts" />
 <TypeScriptCompile Include="App\src\app\utils\AppContants.ts" />
 <!-- Don't publish the SPA source files, but do show them in the project files list -->
 <Content Remove="$(SpaRoot)**" />
 <None Include="$(SpaRoot)**" Exclude="$(SpaRoot)node_modules\**" />
</ItemGroup>

<ItemGroup>
 <Folder Include="Properties\PublishProfiles\" />
</ItemGroup>

<Target Name="DebugEnsureNodeEnv" BeforeTargets="Build" Condition=" '$(Configuration)' == 'Debug' And !Exists('$(SpaRoot)node_modules') ">
 <!-- Ensure Node.js is installed -->
 <Exec Command="node --version" ContinueOnError="true">
   <Output TaskParameter="ExitCode" PropertyName="ErrorCode" />
 </Exec>
 <Error Condition="'$(ErrorCode)' != '0'" Text="Node.js is required to build and run this project. To continue, please install Node.js from https://nodejs.org/, and then restart your command prompt or IDE." />
 <Message Importance="high" Text="Restoring dependencies using 'npm'. This may take several minutes..." />
 <Exec WorkingDirectory="$(SpaRoot)" Command="npm install" />
</Target>

<Target Name="PublishRunWebpack" AfterTargets="ComputeFilesToPublish">
 <!-- As part of publishing, ensure the JS resources are freshly built in production mode -->
 <Exec WorkingDirectory="$(SpaRoot)" Command="npm install" />
 <Exec WorkingDirectory="$(SpaRoot)" Command="ng build --prod" />
 <Exec WorkingDirectory="$(SpaRoot)" Command="npm run build:ssr -- --prod" Condition=" '$(BuildServerSideRenderer)' == 'true' " />

 <!-- Include the newly-built files in the publish output -->
 <ItemGroup>
   <DistFiles Include="$(SpaRoot)dist\**; $(SpaRoot)dist-server\**" />
   <DistFiles Include="$(SpaRoot)node_modules\**" Condition="'$(BuildServerSideRenderer)' == 'true'" />
   <ResolvedFileToPublish Include="@(DistFiles->'%(FullPath)')" Exclude="@(ResolvedFileToPublish)">
     <RelativePath>%(DistFiles.Identity)</RelativePath>
     <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
   </ResolvedFileToPublish>
 </ItemGroup>
</Target>

In Startup.cs

services.AddSpaStaticFiles(configuration =>
            {
                configuration.RootPath = "ClientApp/dist";
            });

 app.UseSpa(spa =>
            {
                spa.Options.SourcePath = "ClientApp";
                if (env.IsDevelopment())
                {
                    spa.UseAngularCliServer(npmScript: "start");
                }
            });

In Angular angular.json

 "options": {
    "outputPath": "dist",

Answer 2

check angular.json file use "outputPath": "dist",

And Startup file

 services.AddSpaStaticFiles(configuration =>
      {
        configuration.RootPath = "ClientApp/dist";
      });