[Preview 8] static assets not found when launchSettings.json is missing

[akorchev]

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Describe the bug

If the Properties/launchSettings.json file is missing static assets from Razor class libraries no longer seem to work. They all lead to HTTP 404 status.

To Reproduce

Steps to reproduce the behavior:

1. Create a blazorserver application using Preview 8: dotnet new blazorserver
2. Install a third party library that has static assets e.g. Blazored.Toast: dotnet add package Blazored.Toast
3. Include its CSS file by adding this line to _Host.cshtml: <link href="_content/Blazored.Toast/blazored-toast.css" rel="stylesheet" />
4. Run the application dotnet run and open the asset by loading https://localhost:5001/_content/Blazored.Toast/blazored-toast.css. You should see the file content.

5. Stop the application and delete the launchSettings.json file from the Properties directory rm -rf Properties/launchSettings.json
6. Run the application dotnet run and open the asset by loading https://localhost:5001/_content/Blazored.Toast/blazored-toast.css. It is no longer found.

Expected behavior

The assets should work with or without launchSettings.json.

[mkArtakMSFT]

Thanks for contacting us, @akorchev.
The StaticWebAssets feature works only in Development by default. You can turn on the feature unconditionally by calling UseStaticWebAssets in the Program.CreateHostBuilder.

[akorchev]

FWIW static assets seem to work just fine in production without calling UseStaticWebAssets or having launchSettings.json. It is probably something else that is causing UseStaticWebAssets to be invoked.