.NET Core 3.0 - HTTP/2 support

You maybe think this is a bad title for this blog post? HTTP/2 support was already available for .NET Core 3.0. So why a blog post with the release of .NET Core 3.0?

The reason is that although it was possible to host an ASP.NET Core 2.0 application behind an HTTP/2 endpoint, the HttpClient class didn’t had support for it!

There are 2 ways that can be used to enable HTTP/2:

Enable HTTP/2 at the instance level

To enable HTTP/2 support at the instance level, you can set the DefaultRequestVersion when creating the HttpClient instance:

For example, the following code creates an HttpClient instance using HTTP/2 as its default protocol:

	var client = new HttpClient()
	{
	BaseAddress = new Uri("https://localhost:5001"),
	DefaultRequestVersion = new Version(2, 0)
	};

view raw Http2Client.cs hosted with ❤ by GitHub

Of course even better is to use the HttpClientFactory to create and configure the HttpClient:

	services.AddHttpClient<ICatalogService, CatalogService>(client =>
	{
	client.BaseAddress = new Uri("https://localhost:5001"),
	client.DefaultRequestVersion = new Version(2, 0)
	})

view raw Http2ClientFactory.cs hosted with ❤ by GitHub

Enable HTTP/2 at the request level

It is also possible to create a single request using the HTTP/2 protocol:

	var client = new HttpClient() { BaseAddress = new Uri("https://localhost:5001") };
	using (var request = new HttpRequestMessage(HttpMethod.Get, "/") { Version = new Version(2, 0) })
	using (var response = await client.SendAsync(request))
	Console.WriteLine(response.Content);

view raw Http2Request.cs hosted with ❤ by GitHub

Remark: Remember that HTTP/2 needs to be supported by both the server and the client. If either party doesn't support HTTP/2, both will use HTTP/1.1.