dotnet-features.md

Table of Contents

1. Propagate headers with .NET Core Web API

• StreamConfiguationSource - reading configuration from any Stream source
• ServiceProviderOptions.ValidateOnBuild - validates the dependencis injected into DI
• Module Initializers - Module initializers are very useful when you want to eager load something before anything else executes

[ModuleInitializer]
public static void Magic()
{
    // Some powerful stuff here...
}

• Simplified null checking
• null coalesce operator and parentheses to automagically instantiate collections

private IList<Foo> _foo;

public IList<Foo> ListOfFoo 
    { get { return _foo ?? (_foo = new List<Foo>()); } }

• The 'default' keyword in generic types: T t = default(T);
• LINQ -

"map" => Select
Transforms data from one form into another

"reduce" => Aggregate
Aggregates values into a single result

"filter" => Where
Filters data based on a criteria

• switch expression

// assign value of the switch to a variable
var text = light.Status switch
{
	ON => "Light is on",
	OFF => "Light is off",
	_ => "Unknown status"
}

• null-coalescing operators - var variable = MightReturnNull() ?? "default";
• file-scoped namespaces - namespace MyNameSpace; - begining of file
• Startup Hooks - Register Code to execute before Program.main
• IConfigurationRoot.DebugView()

Propagate headers with .NET Core Web API

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.HeaderPropagation" Version="6.0.10" />
  </ItemGroup>

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers();
builder.Services.AddHeaderPropagation(o =>
 {
     // propogating the HttpRequest Headers
     o.Headers.Add("Authorization");
 });
builder.Services.AddHttpClient("DemoApp").AddHeaderPropagation();

var app = builder.Build();

// Configure the HTTP request pipeline.

app.UseAuthorization();
app.UseHeaderPropagation();
app.MapControllers();

app.Run();