Blazor and .NET6 creates an error: EntrypointInvoker in assembly Microsoft.AspNetCore.Components.WebAssembly

[erossini]

I have my simple project with Blazor. I updated the project from .NET5 to .NET6. I deploy to the production environment using Web Deploy. On the production server, I am getting this error

Error: Could not find class: Microsoft.AspNetCore.Components.WebAssembly.Hosting:EntrypointInvoker in assembly Microsoft.AspNetCore.Components.WebAssembly

The configuration of Web Deploy is

[TanayParikh]

Hello, thanks for contacting us. The EntrypointInvoker was removed in .NET 6 (via #31769). This seems to indicate the app is still TFM 5. Could you please show us what the .csproj looks like for this project?

[ghost]

Hi @erossini. We have added the "Needs: Author Feedback" label to this issue, which indicates that we have an open question for you before we can take further action. This issue will be closed automatically in 7 days if we do not hear back from you by then - please feel free to re-open it if you come back to this issue after that time.

[erossini]

This is the csproj

<Project Sdk="Microsoft.NET.Sdk.BlazorWebAssembly">

  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly" Version="6.0.0" />
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="6.0.0" PrivateAssets="all" />
    <PackageReference Include="System.Net.Http.Json" Version="6.0.0" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\PSC.Blazor.Components.DataTable\PSC.Blazor.Components.DataTable.csproj" />
  </ItemGroup>

  <ItemGroup>
    <Content Update="wwwroot\img\psc_logo.png">
      <PackagePath>\</PackagePath>
      <Pack>True</Pack>
    </Content>
  </ItemGroup>

</Project>

[pranavkm]

@erossini do you also mind including the obj\project.assets.json for this file? It might be one of your references is causing an older version of blazor.webassembly.js to be used, instead of the 6.0.0 version, and the resolved package references might give us some hints. Alternatively, if there's a minimal app you could share with us that reproduces the problem, that would be great.

[ghost]

Hi @erossini. We have added the "Needs: Author Feedback" label to this issue, which indicates that we have an open question for you before we can take further action. This issue will be closed automatically in 7 days if we do not hear back from you by then - please feel free to re-open it if you come back to this issue after that time.

[erossini]

This is the project.assets.json

project.assets.zip

[legistek]

Same problem here. I cleared out all bin/obj and other intermediate files I could find.

[legistek]

Ohh but clearing my browser cache fixed it. Try that!

[erossini]

ohh @legistek you are right. It made me crazy... simple solution... Thank you everybody! Here the result

[pranavkm]

Do you have your server configured to include the correct cache headers? For instance, in a Blazor hosted app, or in development, Blazor will include the following headers when serving this file:

If you are unable to configure the server headers, you could consider using some cache busting mechanism such as adding a nonce to your blazor.webassembly.js script src.

[erossini]

Do you have your server configured to include the correct cache headers? For instance, in a Blazor hosted app, or in development, Blazor will include the following headers when serving this file:

If you are unable to configure the server headers, you could consider using some cache busting mechanism such as adding a nonce to your blazor.webassembly.js script src.

I use an hosting provider and I don't have a lot of option to change the configuration of the server. When you say "cache busting mechanism", what do you mean? How can I do that?

I saw those links:

• https://docs.microsoft.com/en-us/aspnet/core/blazor/security/content-security-policy?view=aspnetcore-5.0
• https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/blazor/security/content-security-policy.md
• Nonce/Hash in Blazor (CSP) AspNetCore.Docs#22121

[legistek]

Good to know @pranavkm thanks! My only hesitation though is won't that hurt us with those large AOT payloads?

[erossini]

Good to know @pranavkm thanks! My only hesitation though is won't that hurt us with those large AOT payloads?

Why do you use AOT? In my test, it is working also without it

[legistek]

Good to know @pranavkm thanks! My only hesitation though is won't that hurt us with those large AOT payloads?

Why do you use AOT? In my test, it is working also without it

I'm just asking if the HTTP headers prohibited caching, wouldn't that make it slower for users to download the application after the first visit? I just mention AOT because it adds significant file size.

[pranavkm]

@legistek it's specifically for the blazor.webassembly.js file. Blazor manages downloading all other files which does not rely on the browser's HTTP cache. You can verify this by looking at your network tab after the app has been initialized once.

[legistek]

Ah very clever! Thanks for clarifying!

[ghost]

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[Swimburger]

Ran into the same issue, but it wasn't in the browser cache, it was in the CDN cache (Cloudflare in my case).
Don't forget to purge the cache.

[ghost]

Ran into the same issue, but it wasn't in the browser cache, it was in the CDN cache (Cloudflare in my case). Don't forget to purge the cache.

In my case the response header includes "x-cdn: Imperva" only when I'm off the corporate VPN. Get back on the VPN and the x-cdn falls off, and I see different values for content-length + ETag.

[SteveDunn]

Ran into the same issue, but it wasn't in the browser cache, it was in the CDN cache (Cloudflare in my case). Don't forget to purge the cache.

I'm getting the same issue with an Azure CDN. It must be the caching as the same app works from an in-private window

[SteveDunn]

I found that this works: change the line where you reference the .js file and add a version to the url, e.g.

<script src="_framework/blazor.webassembly.js?version=6"></script>