Prefer request hostName and hostPort in ReactorServerHttpRequest

Backport of 682a4d53 and 9624ea39

Closes gh-29974

build.gradle

@@ -29,7 +29,7 @@ configure(allprojects) { project ->
 		imports {
 			mavenBom "com.fasterxml.jackson:jackson-bom:2.12.7"
 			mavenBom "io.netty:netty-bom:4.1.89.Final"
-			mavenBom "io.projectreactor:reactor-bom:2020.0.27"
+			mavenBom "io.projectreactor:reactor-bom:2020.0.29"
 			mavenBom "io.r2dbc:r2dbc-bom:Arabba-SR13"
 			mavenBom "io.rsocket:rsocket-bom:1.1.3"
 			mavenBom "org.eclipse.jetty:jetty-bom:9.4.51.v20230217"

spring-web/src/main/java/org/springframework/http/server/reactive/ReactorServerHttpRequest.java

@@ -24,7 +24,6 @@ import java.util.concurrent.atomic.AtomicLong;
 import javax.net.ssl.SSLSession;
 
 import io.netty.channel.Channel;
-import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.cookie.Cookie;
 import io.netty.handler.ssl.SslHandler;
 import org.apache.commons.logging.Log;
@@ -80,42 +79,15 @@ class ReactorServerHttpRequest extends AbstractServerHttpRequest {
 		return new URI(resolveBaseUrl(request) + resolveRequestUri(request));
 	}
 
-	private static URI resolveBaseUrl(HttpServerRequest request) throws URISyntaxException {
-		String scheme = getScheme(request);
-
-		InetSocketAddress hostAddress = request.hostAddress();
-		if (hostAddress != null) {
-			return new URI(scheme, null, hostAddress.getHostString(), hostAddress.getPort(), null, null, null);
-		}
-
-		String header = request.requestHeaders().get(HttpHeaderNames.HOST);
-		if (header != null) {
-			final int portIndex;
-			if (header.startsWith("[")) {
-				portIndex = header.indexOf(':', header.indexOf(']'));
-			}
-			else {
-				portIndex = header.indexOf(':');
-			}
-			if (portIndex != -1) {
-				try {
-					return new URI(scheme, null, header.substring(0, portIndex),
-							Integer.parseInt(header.substring(portIndex + 1)), null, null, null);
-				}
-				catch (NumberFormatException ex) {
-					throw new URISyntaxException(header, "Unable to parse port", portIndex);
-				}
-			}
-			else {
-				return new URI(scheme, header, null, null);
-			}
-		}
-
-		throw new IllegalStateException("Neither local hostAddress nor HOST header available");
+	private static String resolveBaseUrl(HttpServerRequest request) {
+		String scheme = request.scheme();
+		int port = request.hostPort();
+		return scheme + "://" + request.hostName() + (usePort(scheme, port) ? ":" + port : "");
 	}
 
-	private static String getScheme(HttpServerRequest request) {
-		return request.scheme();
+	private static boolean usePort(String scheme, int port) {
+		return ((scheme.equals("http") || scheme.equals("ws")) && (port != 80)) ||
+				((scheme.equals("https") || scheme.equals("wss")) && (port != 443));
 	}
 
 	private static String resolveRequestUri(HttpServerRequest request) {