What’s new?

Here’s a sampling of the great new features and improvements in ASP.NET Core for .NET 7:

• Servers and runtime
  • Rating limiting: Limit the rate of handled requests using flexible endpoint configuration and policies.
  • Output caching: Configure output caching to reduce to more efficiently handle request.
  • Request decompression: Accept requests with compressed content.
  • HTTP/3: Built-in support for HTTP/3, the latest HTTP version based on the new QUIC multiplexed transport protocol.
  • WebSockets over HTTP/2: Use WebSockets over HTTP/2 connections.
  • WebTransport (experimental): Create streams and data grams over HTTP/3 with experimental support for WebTransport.
• Minimal APIs
  • Endpoint filters: Use endpoint filters to run cross-cutting code before or after a route handler.
  • Typed results: Return strongly typed results from minimal APIs.
  • Route groups: Organize groups of endpoints with a common prefix
• gRPC
  • JSON transcoding: Expand the reach of your gRPC services by also exposing them as JSON-based APIs
  • OpenAPI with JSON transcoding (experimenal): Use experimental support for generating OpenAPI specs for your gRPC JSON transcoded services.
  • gRPC health checks: Report and check the health of gRPC server apps.
  • gRPC client AddCallCredentials : Create clients that send authorized requests using bearer tokens.
• SignalR
  • Client results: Return client results to the server in response to requests from the server.
• MVC
  • Nullable view and page models: Nullable page and view models are now supported to improve the experience when using null state checking.
• Blazor
  • Custom elements: Build standard HTML custom elements with Blazor to integrate Blazor components with any JavaScript-based app.
  • Handle location changing events: Intercept location changing events to create custom user experiences when navigating.
  • Bind after/get/set modifiers: Run async logic after data binding and independently control how data binding gets and sets the data.
  • Dynamic authentication requests: Create dynamic authentication requests at runtime with custom parameters to handle advanced authentication scenarios in Blazor WebAssembly apps.
  • Improved JavaScript interop on WebAssembly: Optimize JavaScript interop call when running on WebAssembly using the new [JSImport]/[JSExport] support.
  • WebAssembly SIMD & exception handling: Improve performance with .NET WebAssembly ahead-of-time (AOT) compilation using WebAssembly SIMD and exception handling support. 

Branca is a catchy name for IETF XChaCha20-Poly1305 AEAD message with an additional version number and timestamp. It is well suited to be used as an authenticated and encrypted API token. Branca specification does not specify the payload format. 

C# for Beginners | Full 2-hour course - YouTube

00:00:00 – Start
00:00:09 – What is C#
00:01:27 – C#: Hello World
00:06:01 – C#: The Basics of Strings
00:14:35 – C#: Searching Strings
00:17:27 – C#: Numbers and Integer Math
00:22:04 – C#: Numbers and Integer Precision
00:27:32 – C#: Numbers and Decimals
00:33:10 – C#: Branches (if)
00:44:29 – C#: “Hello World” Explained
00:50:29 – C#: What are Loops?
00:57:42 – C#: Combining Branches and Loops
01:04:34 – C#: Arrays, List, and Collections
01:15:09 – C#: Sort, Search, and Index Lists
01:22:08 – C#: Lists of Other Types
01:29:51 – C#: Debugging
01:34:30 – C#: Object Oriented Programming – Objects and Classes
01:47:20 – C#: Object Oriented Programming – Methods and Members
01:56:02 – C#: Object Oriented Programming – Methods and Exceptions
02:03:00 – C#: Object Oriented Programming – Catching Exceptions 

If you enable our semantic highlighting support then, be sure to try out the included Visual Studio 2019 Light and Dark themes. TypeScript looks great in it too!

NOTE: For semantic highlighting ensure that editor.semanticHighlighting.enabled and csharp.semanticHighlighting.enabled are set to true. 

We’re introducing a new singleton service that will support generating a URL. This new service can be used from middleware, and does not require an HttpContext. For right now the set of things you can link to is limited to MVC actions, but this will expand in 3.0. 

Revolution Lightbox is a full blown multimedia responsive lightbox that runs on all major browsers and mobile devices like iPhone, iPad, iOS, Android or Windows mobile. It has support for image, video (mp4), audio (mp3), Vimeo, YouTube, iFrame, AJAX, HTML content, Google maps and flash. 

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        // Web API configuration and services

        // Web API routes
        config.MapHttpAttributeRoutes();
    }
}

public class VideoStream
{
    private readonly string _filename;
    private long _contentLength;

    public long FileLength
    {
        get { return _contentLength; }
    }

    public VideoStream(string videoPath)
    {
        _filename = videoPath;
        using (var video = File.Open(_filename, FileMode.Open, FileAccess.Read, FileShare.Read))
        {
            _contentLength = video.Length;
        }
    }

    public async void WriteToStream(Stream outputStream,
        HttpContent content, TransportContext context)
    {
        try
        {
            var buffer = new byte[65536];

            using (var video = File.Open(_filename, FileMode.Open, FileAccess.Read, FileShare.Read))
            {
                var length = (int)video.Length;
                var bytesRead = 1;

                while (length > 0 && bytesRead > 0)
                {
                    bytesRead = video.Read(buffer, 0, Math.Min(length, buffer.Length));
                    await outputStream.WriteAsync(buffer, 0, bytesRead);
                    length -= bytesRead;
                }
            }
        }
        catch (HttpException)
        {
            return;
        }
        finally
        {
            outputStream.Close();
        }
    }
}

while (length > 0 && bytesRead > 0)
{
    bytesRead = video.Read(buffer, 0, Math.Min(length, buffer.Length));
    await outputStream.WriteAsync(buffer, 0, bytesRead);
    length -= bytesRead;
}

public class VideoController : ApiController
{
    [Route("api/video/{ext}/{fileName}")]
    public HttpResponseMessage Get(string ext, string fileName)
    {
        string videoPath = HostingEnvironment.MapPath(string.Format("~/Videos/{0}.{1}", fileName, ext));
        if (File.Exists(videoPath))
        {
            FileInfo fi = new FileInfo(videoPath);
            var video = new VideoStream(videoPath);

            var response = Request.CreateResponse();

            response.Content = new PushStreamContent((Action<Stream, HttpContent, TransportContext>)video.WriteToStream,
                new MediaTypeHeaderValue("video/" + ext));

            response.Content.Headers.Add("Content-Disposition", "attachment;filename=" + fi.Name.Replace(" ", ""));
            response.Content.Headers.Add("Content-Length", video.FileLength.ToString());

            return response;
        }
        else
        {
            return Request.CreateResponse(HttpStatusCode.NotFound);
        }
    }
}

[Route("api/video/{ext}/{fileName}")]

api/video/mp4/sample

string videoPath = HostingEnvironment.MapPath(string.Format("~/Videos/{0}.{1}", fileName, ext));

var video = new VideoStream(videoPath);

var response = Request.CreateResponse();

response.Content = new PushStreamContent((Action<Stream, HttpContent, TransportContext>)video.WriteToStream, new MediaTypeHeaderValue("video/" + ext));

response.Content.Headers.Add("Content-Disposition", "attachment;filename=" + fileName);
response.Content.Headers.Add("Content-Length", video.FileLength.ToString());

if(File.Exists(videoPath))
{
    // removed for bravity
}
else
{
    return Request.CreateResponse(HttpStatusCode.NotFound);
}

public class HomeController : Controller
{
    // GET: Home
    public ActionResult Index()
    {
        return View();
    }
}

<div>
    <div>
        <video width="480" height="270" controls="controls" preload="auto">
            <source src="/api/video/mp4/sample" type="video/mp4" />
            Your browser does not support the video tag.
        </video>
    </div>
</div>

Security Advisory Notice for 16.6.2

CVE-2020-1108 / CVE-2020-1108.NET Core Denial of Service Vulnerability

To comprehensively address CVE-2020-1108, Microsoft has released updates for .NET Core 2.1 and .NET Core 3.1. Customers who use any of these versions of .NET Core should install the latest version of .NET Core. See the Release Notes for the latest version numbers and instructions for updating .NET Core.

CVE-2020-1202 / CVE-2020-1203 Diagnostics Hub Standard Collector Service Elevation of Privilege Vulnerability

An elevation of privilege vulnerability exists when the Diagnostics Hub Standard Collector or the Visual Studio Standard Collector fails to properly handle objects in memory.

CVE-2020-1293 / CVE-2020-1278 / CVE-2020-1257 Diagnostics Hub Standard Collector Service Elevation of Privilege Vulnerability

An elevation of privilege vulnerability exists when the Diagnostics Hub Standard Collector Service improperly handles file operations

Top Issues Fixed in Visual Studio 2019 version 16.6.2

• Visual Studio 2019 16.60 hang at run or build when modified not saved in C++/CLI project
• An unhandled exception of type 'System.NullReferenceException' occurred in Microsoft.VisualStudio.DesignTools.WpfTap.dll
• Recurring null reference when reopening documents
• "Create new project" dialog search does not find templates for third-party language providers
• IntelliSense shows that "tilde-slash" (~/) points to ASP .NET Core 3.1 project root instread of wwwroot subfolder after upgrading Visual Studio Enterprise 16.5.6->16.6.0
• Fixed a compiler error (error C2475: redefinition; 'constexpr' specifier mismatch) affecting std::atomic when compiled as C++/CX in C++17 mode.
• URL completion values and format was fixed in Razor views. App-relative URL format is now used again and the values in the URL completion list show files and folders rooted under app root, i.e. wwwroot.
• Fixed a crash when using snippets.
• Restore item templates that could be hidden by extensions.