Document what's new in ASP.NET Core for .NET 9 Preview 5

[danroth27]

Description

Update the "What's new in ASP.NET Core 9.0" for .NET 9 Preview 5

Page URL

https://learn.microsoft.com/en-us/aspnet/core/release-notes/aspnetcore-9.0?view=aspnetcore-8.0

Content source URL

https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/release-notes/aspnetcore-9.0.md

Document ID

4e75ad25-2c3f-b28e-6a91-ac79a9c683b6

Article author

@Rick-Anderson @tdykstra @guardrex

[mkArtakMSFT]

@MackinnonBuck please add a comment documenting the ReconnectionUI work that you've done.

[mkArtakMSFT]

@javiercn please add a comment with the Static Assets compression work that you've done.
Also the new APIs for getting the current RenderMode please.

[mkArtakMSFT]

@halter73 please add a comment documenting the AuthenticationStateProvider work.

[MackinnonBuck]

Improved Blazor Server reconnection experience:

The following changes have been made to the default Blazor Server reconnection experience:

• Reconnect timing now uses an exponential backoff strategy. The first several reconnection attempts will happen in rapid succession before a delay gradually gets introduced between attempts. This behavior can be customized by specifying a function to compute the retry interval. For example:

  Blazor.start({
    circuit: {
      reconnectionOptions: {
        retryIntervalMilliseconds: (previousAttempts, maxRetries) => previousAttempts >= maxRetries ? null : previousAttempts * 1000,
      },
    },
  });

• When the user navigates back to an app with a disconnected circuit, a reconnect attempt gets immediately made rather than waiting for the duration of the next reconnect interval. This especially improves the user experience when navigating to an app in a browser tab that has gone to sleep.
• If a reconnection attempt reaches the server, but reconnection fails because server had already released the circuit, a refresh occurs automatically. This prevents the user from having to manually refresh the page if it's likely going to result in a successful reconnection.
• The styling of the default reconnect UI has been modernized.