Skip to main content

ASP.NET Core Architect David Fowler's hidden gems in 2.1

ASP.NET Architect David FowlerOpen source ASP.NET Core 2.1 is out, and Architect David Fowler took to twitter to share some hidden gems that not everyone knows about. Sure, it's faster, builds faster, runs faster, but there's a number of details and fun advanced techniques that are worth a closer look at.

.NET Generic Host

ASP.NET Core introduced a new hosting model. .NET apps configure and launch a host.

The host is responsible for app startup and lifetime management. The goal of the Generic Host is to decouple the HTTP pipeline from the Web Host API to enable a wider array of host scenarios. Messaging, background tasks, and other non-HTTP workloads based on the Generic Host benefit from cross-cutting capabilities, such as configuration, dependency injection (DI), and logging.

This means that there's not just a WebHost anymore, there's a Generic Host for non-web-hosting scenarios. You get the same feeling as with ASP.NET Core and all the cool features like DI, logging, and config. The sample code for a Generic Host is up on GitHub.

IHostedService

A way to run long running background operations in both the generic host and in your web hosted applications. ASP.NET Core 2.1 added support for a BackgroundService base class that makes it trivial to write a long running async loop. The sample code for a Hosted Service is also up on GitHub.

Check out a simple Timed Background Task:

public Task StartAsync(CancellationToken cancellationToken)

{

   _logger.LogInformation("Timed Background Service is starting.");


   _timer = new Timer(DoWork, null, TimeSpan.Zero, 

        TimeSpan.FromSeconds(5));


   return Task.CompletedTask;

}

Fun!

Windows Services on .NET Core

You can now host ASP.NET Core inside a Windows Service! Lots of people have been asking for this. Again, no need for IIS, and you can host whatever makes you happy. Check out Microsoft.AspNetCore.Hosting.WindowsServices on NuGet and extensive docs on how to host your own ASP.NET Core app without IIS on Windows as a Windows Service.

public static void Main(string[] args)

{

    var pathToExe = Process.GetCurrentProcess().MainModule.FileName;

    var pathToContentRoot = Path.GetDirectoryName(pathToExe);


    var host = WebHost.CreateDefaultBuilder(args)

        .UseContentRoot(pathToContentRoot)

        .UseStartup<Startup>()

        .Build();


    host.RunAsService();

}

IHostingStartup - Configure IWebHostBuilder with an Assembly Attribute

Simple and clean with source on GitHub as always.

[assembly: HostingStartup(typeof(SampleStartups.StartupInjection))]

Shared Source Packages

This is an interesting one you should definitely take a moment and pay attention to. It's possible to build packages that are used as helpers to share source code. We internally call these "shared source packages." These are used all over ASP.NET Core for things that should be shared BUT shouldn't be public APIs. These get used but won't end up as actual dependencies of your resulting package.

They are consumed like this in a CSPROJ. Notice the PrivateAssets attribute.

<PackageReference Include="Microsoft.Extensions.ClosedGenericMatcher.Sources" PrivateAssets="All" Version="" />

<PackageReference Include="Microsoft.Extensions.ObjectMethodExecutor.Sources" PrivateAssets="All" Version="" />

ObjectMethodExecutor

If you ever need to invoke a method on a type via reflection and that method could be async, we have a helper that we use everywhere in the ASP.NET Core code base that is highly optimized and flexible called the ObjectMethodExecutor.

The team uses this code in MVC to invoke your controller methods. They use this code in SignalR to invoke your hub methods. It handles async and sync methods. It also handles custom awaitables and F# async workflows

SuppressStatusMessages

A small and commonly requested one. If you hate the output that dotnet run gives when you host a web application (printing out the binding information) you can use the new SuppressStatusMessages extension method.

WebHost.CreateDefaultBuilder(args)

    .SuppressStatusMessages(true)

    .UseStartup<Startup>();

AddOptions

They made it easier in 2.1 to configure options that require services. Previously, you would have had to create a type that derived from IConfigureOptions<TOptions>, now you can do it all in ConfigureServices via AddOptions<TOptions>

public void ConfigureServicdes(IServiceCollection services)

{

    services.AddOptions<MyOptions>()

        .Configure<IHostingEnvironment>((o,env) =>

        {

            o.Path = env.WebRootPath;

        });

}

IHttpContext via AddHttpContextAccessor

You likely shouldn't be digging around for IHttpContext, but lots of folks ask how to get to it and some feel it should be automatic. It's not registered by default since having it has a performance cost. However, in ASP.NET Core 2.1 a PR was put in for an extension method that makes it easy IF you want it.

services.AddHttpContextAccessor();

So ASP.NET Core 2.1 is out and ready to go. 

New features in this release include:

Check out What's New in ASP.NET Core 2.1 in the ASP.NET Core docs to learn more about these features. For a complete list of all the changes in this release, see the release notes.

Go give it a try. Follow this QuickStart and you can have a basic Web App up in 10 minutes.

Sponsor: Check out JetBrains Rider: a cross-platform .NET IDE. Edit, refactor, test and debug ASP.NET, .NET Framework, .NET Core, Xamarin or Unity applications. Learn more and download a 30-day trial!


© 2018 Scott Hanselman. All rights reserved.
     


from Scott Hanselman's Blog http://feeds.hanselman.com/~/551355546/0/scotthanselman~ASPNET-Core-Architect-David-Fowlers-hidden-gems-in.aspx
Labels:

Comments

Post a Comment

Popular posts from this blog

dotnet sdk list and dotnet sdk latest

Can someone make .NET Core better with a simple global command? Fanie Reynders did and he did it in a simple and elegant way. I'm envious, in fact, because I spec'ed this exact thing out in a meeting a few months ago but I could have just done it like he did and I would have used fewer keystrokes! Last year when .NET Core was just getting started, there was a "DNVM" helper command that you could use to simplify dealing with multiple versions of the .NET SDK on one machine. Later, rather than 'switching global SDK versions,' switching was simplified to be handled on a folder by folder basis. That meant that if you had a project in a folder with no global.json that pinned the SDK version, your project would use the latest installed version. If you liked, you could create a global.json file and pin your project's folder to a specific version. Great, but I would constantly have to google to remember the format for the global.json file, and I'd constan...
Post a Comment
Read more

15 Web Design Trends to Watch in 2018

The modern world is full of extraordinary things that influence our imagination and mood. Our soul needs a perfect atmosphere and impressive spots. To apply such things in practice, we have submitted the list of the web trends that deserve your attention. Robert frost design analysis will meet all your wishes and expectations. Image Source Web Design Trends to Watch in 2018 1. More Organic Shapes Until this year, web design, as well as mobile design, were based on the right-angled and sharp-edged shapes. However, it seems that this year will bring some significant changes in the field of web design. The recent trends will offer the absolute rounded corners. In addition, the web design of 2018 will make the real things look like the cartoonish ones. 2.   Bold Minimalism Although some of you may think that this web design trend will not attract the Internet users. Indeed, the notion of minimalism is often associated with boredom and dullness. However, in this case, bold ...
Post a Comment
Read more

R vs Python for Machine Learning

There are so many things to learn before to choose which language is good for Machine Learning. We will discuss each and everything about R as well as Python and the situation or problem in which situation we have to use which language. Let’s start Python and R are the two most Commonly used Programming Languages for Machine Learning and because of the popularity of both the languages Novice or you can say fresher are getting confused, whether they should choose R or Python language to commence their career in the Machine learning domain. Don’t worry guys through this article we will discuss R vs Python for Machine Learning. So, without exaggerating this article let’s get started. We will start it from the very Basics things or definitions. R vs Python for Machine Learning Introduction R is a programming language made by statisticians and data miners for statistical analysis and graphics supported by R foundation for statistical computing. R also provides high-quality graphics and...
1 comment
Read more