[External] : Re: Http3 Client times out for an untrusted certificate

[Daniel Fuchs]

Hi Josiah,

On 07/11/2025 09:46, Daniel Fuchs wrote:
> Does the server supports https? Because if the server does not
> support https it might just be trying to read the request line
> before responding, and the client might be waiting for the server
> hello. The same would happen with HTTP/1.1 if you tried to use
> https with a server that only supports http.

So that seems to be the issue.
I had a look at your script - and I believe that if
you had used HttpsServer.create() instead of HttpServer.create()
you would have got the exception as expected.

I am not sure there's much we can do there. If you try to send
an HTTP/1.1 https:// request to that server youn will observe
the same behavior.

Specifically try this:

```
     // http1 server on tcp 8080
     // btw what if we made a conveniece method? I'll contribute it 
myself, just say the word
     var http1 = HttpServer.create(new InetSocketAddress(8080), 0);
     http1.createContext("/", ctx -> ctx.sendResponseHeaders(101, -1));
     http1.start();

     var client = HttpClient.newBuilder()
	.version(HttpClient.Version.HTTP_1_1)
	.build();
     var request = HttpRequest.newBuilder()
	.uri(URI.create("https://localhost:8080/"))
	.build();
     System.out.println("req: " + request);
     var resp = client.send(request, HttpResponse.BodyHandlers.ofString());
     System.out.println("resp: " + resp);
```

This has the same behaviour and does not involve HTTP/3.
To see the exception, add this to the request in your
original script:

```
import java.net.http.HttpOption;
import static java.net.http.HttpOption.H3_DISCOVERY;
import static java.net.http.HttpOption.Http3DiscoveryMode.HTTP_3_URI_ONLY;

...

      HttpRequest.newBuilder().uri(URI.create("https://localhost:8080"))
         .setOption(H3_DISCOVERY, HTTP_3_URI_ONLY)   <<<<< HTTP/3 only
         .GET().build(),
```

this will prevent the client from falling back to TCP.

best regards,

-- daniel