Offline loading #10556

6 Answer(s)

• 

  0

  AI-Bot created 6 months ago

  Support Team ABP Agent

  • Your screenshot shows the app trying to load bootstrap.bundle.min.js.map, bootstrap.min.css.map, and dotnet.runtime*.js.map and getting 404. These .map files are source maps used only for debugging. They are not required for offline/PWA runtime. You can ignore these warnings, or disable source-map generation in your build pipeline if you don’t want the console noise.

  • The real problem in the screenshot is this runtime error:

    WebAssembly.Compile is disallowed on the main thread if the buffer size is larger than 4KB ...

    This typically happens when the browser blocks synchronous WASM compilation on the main thread (often due to browser/runtime constraints). In an offline/PWA scenario, this is frequently triggered by an incorrect or incomplete service-worker cache, where some of the Blazor runtime files (dotnet.native*.wasm, dotnet.runtime*.js, dlls, etc.) are served from cache in an unexpected way/version mismatch.

  Solution

  1. Use ABP’s standard PWA service worker setup (and don’t customize it until it works)
     • Ensure your Blazor WASM client has:
       • wwwroot/service-worker.js
       • wwwroot/service-worker.published.js
     • Ensure your *.Blazor.Client.csproj includes:

  <PropertyGroup>
       <ServiceWorkerAssetsManifest>service-worker-assets.js</ServiceWorkerAssetsManifest>
     </PropertyGroup>
  
     <ItemGroup>
       <ServiceWorker Include="wwwroot\service-worker.js"
                      PublishedContent="wwwroot\service-worker.published.js" />
     </ItemGroup>
  

  2. Ensure your published service worker caches the required Blazor assets Use the standard service-worker.published.js pattern (the important part is that it caches .dll, .wasm, .js, .json, .css, etc. from service-worker-assets.js). ABP docs include the canonical version; make sure yours matches that behavior.

  3. After deploying changes, force a clean service-worker update

     • In browser dev tools → Application → Service Workers:
       • Unregister the service worker
     • Clear site data (cache storage included)
     • Reload, then test offline again

  4. Verify the app is actually caching the Blazor runtime

     • DevTools → Application → Cache Storage → check the offline-cache-* entries
     • Confirm you see cached entries for:
       • index.html
       • service-worker-assets.js
       • dotnet.native*.wasm
       • dotnet.runtime*.js
       • *.dll

  If you do the above and offline still fails with the same WebAssembly.Compile... error, then your service-worker.published.js is almost certainly serving a stale/incorrect cached runtime asset (version mismatch). The “unregister + clear site data” step resolves that in most cases.

  Sources

  • https://abp.io/docs/10.1/framework/ui/blazor/pwa-configuration
  • https://learn.microsoft.com/en-us/aspnet/core/blazor/progressive-web-app
  • https://aka.ms/blazor-offline-considerations

  ---

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• 

  0

  maliming created 6 months ago

  Support Team Fullstack Developer

  Hi,

  Thanks for the screenshot. Let me address the errors you're seeing:

  Yellow warnings (non-critical): The three "DevTools failed to load source map" warnings (.map files returning 404) are harmless — these are only needed for debugging and don't affect your app's functionality.

  Red error: The MONO_WASM: ParseAttributes:2e code generation failed: RangeError: WebAssembly.Compile is disallowed on the main thread, if the buffer size is larger than 4KB is a Chrome browser limitation. Chrome restricts synchronous WebAssembly compilation on the main thread for modules larger than 4KB. When this happens, the Mono runtime falls back to interpreted execution for that method, which is usually non-fatal — the app should still work, just slightly slower for that code path.

  Could you provide a bit more context?

  1. What version of .NET / ABP are you using?
  2. Does the app load correctly when online? Or does it fail in both online and offline modes?
  3. Are you seeing a blank/stuck loading screen, or does it actually crash with an error?
  4. Can you try it in the latest Chrome browser?

  If the app works online but fails only when offline, the issue is likely related to the service worker not caching all required Blazor assets properly. In that case, try clearing the browser cache and service worker registration (DevTools → Application → Storage → Clear site data), then reload online first to let the service worker re-cache everything.

  Thanks

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  0

  DowletCsharp created 6 months ago

  We use .net 10with Abp 10.1.10. When app online it works correctly. Even we don't have warnings like bootstrap.bundle.min.js.map loads. But in offline we see the errors above when loading and with such errors we cannot complete authorization. After authorization we see this page: we see

  Is there any way to load only offline?

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  0

  maliming created 6 months ago

  Support Team Fullstack Developer

  hi

  Can you share a demo app?

  I will check it in offline mode.

  liming.ma@volosoft.com

  Thanks.

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  0

  DowletCsharp created 6 months ago

  Our projects created in Abp Studio. And this problem appeared in production. We use Blazor WASM for our projects. All projects created via Abp Studio with BlazorWASM has this error in production. Our projects are aimed to work in local network without internet.

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• 

  0

  maliming created 6 months ago

  Support Team Fullstack Developer

  Hi,

  The console errors you're seeing are not the root cause of your offline loading issue:

  • The source map warnings (.map files returning 404) are harmless — they are only used for debugging in DevTools and have no effect on app behavior.
  • The MONO_WASM: WebAssembly.Compile is disallowed on the main thread warning is a Chrome browser limitation for synchronous WASM compilation. The runtime falls back to interpreted mode for that method and the app should still continue running.

  These warnings likely appear in online mode too, but you didn't notice because everything worked fine.

  To help diagnose the actual offline loading problem, could you provide more details?

  1. When the app fails to load offline, what exactly happens — is it a blank/white screen, a loading spinner that never finishes, or does it show a specific error page?
  2. By "offline", do you mean the device has no internet at all, or that it's running on a local network without public internet access?
  3. Is your authentication server (OpenIddict) hosted on the same local network and accessible from the client device without internet?
  4. Could you share the exact steps to reproduce this issue using a freshly created ABP Studio Blazor WebAssembly project? This will help us isolate whether it's a template issue or something specific to your setup.

  Thanks

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