Cosmetic improvements for netty client example (dealing with URL argument, readme)

Author: kachayev

README.md

@@ -305,6 +305,8 @@ Note that `poll` would either execute callbacks and returns immediately. If ther
 
 Have a look at the [quiche4j-examples](quiche4j-examples/src/main/java/io/quiche4j/examples/) folder for more complete examples on how to use the Quiche4j API to work with HTTP/3 protocol.
 
+Examples package has [`Http3NettyClient`](quiche4j-examples/src/main/java/io/quiche4j/examples/Http3NettyClient.java) with a toy implementation of HTTP/3 client to show case the idea of how `quiche4j` connection state management could be integrated with [Netty](https://netty.io/) I/O primitives.
+
 ### Errors Hanlding
 
 Native JNI code propagates errors using return codes (typically the return code < 0 means either DONE or failed). For example, [`quiche::Error`](https://github.com/cloudflare/quiche/blob/204d693bb543e12a605073181ae605eacb743039/src/lib.rs#L320-L365) enum. `Quiche4j` follows the same convention instead of throwing Java exceptions to ensure good perfomance and compatibility with async runtimes (catching exception in async environemnt might be somewhat problematic). See [`Quiche.ErrorCode`](src/main/java/io/quiche4j/Quiche.java) and [`Http3.ErrorCode`](src/main/java/io/quiche4j/http3/Http3.java) for more details.

http3-client.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 set -eu -o pipefail
 
-URL=${1:-"http://quic.tech:8443"}
+URL=${1:-"https://quic.tech:8443"}
 
 java \
     -cp quiche4j-examples/target/quiche4j-examples-*.jar \

quiche4j-examples/src/main/java/io/quiche4j/examples/Http3NettyClient.java

@@ -5,6 +5,8 @@
 
 import java.io.IOException;
 import java.net.InetSocketAddress;
+import java.net.URI;
+import java.net.URISyntaxException;
 import java.nio.channels.ClosedChannelException;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
@@ -356,9 +358,23 @@ public HttpOverQuicHandler httpHandler() {
     }
 
     public static void main(String[] args) throws IOException {
+        if (0 == args.length) {
+            System.out.println("Usage: ./http3-netty-client.sh <URL>");
+            System.exit(1);
+        }
+
+        final String url = args[0];
+        final URI uri;
+        try {
+            uri = new URI(url);
+        } catch (URISyntaxException e) {
+            System.out.println("Failed to parse URL " + url);
+            System.exit(1);
+            return;
+        }
+
+        final InetSocketAddress address = new InetSocketAddress(uri.getHost(), uri.getPort());
 
-        final String hostname = "quic.tech";
-        final InetSocketAddress address = new InetSocketAddress(hostname, 8443);
         final EventLoopGroup workerGroup = new NioEventLoopGroup();
         final Config config = new ConfigBuilder(Quiche.PROTOCOL_VERSION)
             .withApplicationProtos(Http3.APPLICATION_PROTOCOL)
@@ -378,7 +394,7 @@ public static void main(String[] args) throws IOException {
         final Http3Config http3config = new Http3ConfigBuilder().build();
 
         final Http3ClientInitializer initializer =
-            new Http3ClientInitializer(address, hostname, config, http3config);
+            new Http3ClientInitializer(address, uri.getHost(), config, http3config);
 
         try {
             final Bootstrap b = new Bootstrap();
@@ -392,8 +408,8 @@ public static void main(String[] args) throws IOException {
             // connection is now ready
             System.out.println("Connection was succesfully established");
 
-            final FullHttpRequest request = new DefaultFullHttpRequest(HTTP_1_1, GET, "/", Unpooled.EMPTY_BUFFER);
-            request.headers().add(HttpHeaderNames.HOST, "quic.tech");
+            final FullHttpRequest request = new DefaultFullHttpRequest(HTTP_1_1, GET, uri.getPath(), Unpooled.EMPTY_BUFFER);
+            request.headers().add(HttpHeaderNames.HOST, uri.getHost());
             request.headers().add(HttpConversionUtil.ExtensionHeaderNames.SCHEME.text(), "https");
 
             long streamId = initializer.httpHandler().sendRequest(request);