The latest release of .NET 8 Preview 5 brings significant additions to ASP.NET Core. Notable enhancements include an improved debugging experience for ASP.NET Core, changes regarding the servers and middleware, the introduction of new features and improvements in Blazor, enhanced API authoring capabilities, seamless reconnect functionality in SignalR, and improvements and changes in authentication and authorization.
Regarding productivity notable advancements have been made to enhance the debugging experience in ASP.NET Core. Specifically, developers will benefit from the introduction of debug customization attributes that facilitate the retrieval of crucial information related to types such as HttpContext, HttpRequest, HttpResponse, and ClaimsPrincipal within the Visual Studio debugger.
In the latest .NET 8 preview 5, developers can experience early support for "seamless reconnects" in SignalR. This new feature aims to minimize downtime for clients facing temporary network disruptions, such as network switches or tunnel passages. By temporarily buffering data on both the server and client sides and acknowledging messages, it ensures a smoother user experience. Currently, this support is limited to .NET clients using WebSockets, and configuration options are not yet available. Developers have the freedom to opt-in to this feature and tweak around options.UseAcks, at HubConnectionBuilder. Upcoming previews are expected to introduce server-side configuration, customizable buffering settings, timeout limits, and expanded support for other transports and clients.
Blazor has also received a significant number of updates in the latest release of .NET 8 Preview 5. Updates like the new Blazor Web App template available through the command line and within the Visual Studio, webcil is now the default packaging format when publishing a Blazor WebAssembly app is being done, and regarding the Blazor WebAssembly, there is no longer requirement for unsafe-eval to be enabled, while specifying a Content Security Policy (CSP).
Also, the Blazor Router component now integrates with endpoint routing to handle both server-side and client-side routing. This integration allows for consistent routing to components regardless of whether server-side or client-side rendering is employed. The new Blazor Web App template includes sample pages, such as Index.razor and ShowData.razor, which utilize endpoint routing and streaming rendering for displaying weather forecast data, with enhanced navigation support expected in future .NET 8 previews.
Blazor Server introduces the ability to enable interactivity for individual components. With the new [RenderModeServer] attribute, developers can activate interactivity for specific components by utilizing the AddServerComponents extension method. This enhancement offers greater flexibility and control when building interactive applications with Blazor Server rendering mode.
The comment section of the original release blog post has generated significant activity, with users engaging in numerous questions and discussions with the development team. Developers are encouraged to explore the comment section for further information and insights.
Generic attributes were introduced in C# 11 and now regarding updates for API authoring, there is support added for generic attributes, providing cleaner alternatives to attributes that previously relied on a System.Type parameter. Generic variants are now available for the following attributes: ProducesResponseType<T>, Produces<T>, MiddlewareFilter<T>, ModelBinder<T>, ModelMetadataType<T>, ServiceFilter<T>, and TypeFilter<T>.
Authentication and authorization, have also seen some changes, ASP.NET Core React and Angular project templates have removed the dependency on Duende IdentityServer. Instead, these templates now utilize the default ASP.NET Core Identity UI and cookie authentication to handle authentication for individual user accounts. Also, a new Roslyn analyzer is introduced in this preview to facilitate the adoption of a more "terser" syntax using the AddAuthorizationBuilder API, where applicable.
Other notable changes include the servers & middleware area; the introduction of the IHttpSysRequestTimingFeature interface allows for the detailed info of timestamp data during request processing when utilizing the HTTP.sys server. Additionally, the ITlsHandshakeFeature interface now exposes the Server Name Indication (SNI) hostname information. The addition of IExceptionHandler interface enables services to be resolved and invoked by the exception handler middleware in order to provide developers with a callback mechanism to handle known exceptions in a centralized location.
Furthermore, regarding Native AOT, the latest preview incorporates enhancements to minimal APIs generated at compile-time. These improvements include support for parameters adorned with the AsParameters attribute and the automatic inference of metadata for request and response types.
Lastly, developers are welcome to leave feedback and follow the progress of the ASP.NET Core in .NET 8 by visiting the official GitHub project repository.