Fix request absolute URI handling

When a request uses an absolute request target with scheme and host
parts, the current absoluteURI() method simply concatenates the Host
header value and the request target URI. For example, with the following
request:

```
GET http://www.example.com:1234/path HTTP/1.1
Host: www.example.com:1234
```

The result of HttpServerRequest.absoluteURI() would then be:

`http://www.example.com:1234www.example.com:1234/path`

With this change, when the request target is absolute, only the path
(and query) are added to the Host value:

`http://www.example.com:1234/path`

Fixes #2830

Author: tmonney

vertx-web/src/main/java/io/vertx/ext/web/impl/ForwardedParser.java

@@ -133,7 +133,16 @@ private void calculate() {
     if (host != null) {
       this.authority = HostAndPort.create(host, port);
       host = host + (port >= 0 ? ":" + port : "");
-      absoluteURI = scheme + "://" + host + delegate.uri();
+
+      String uri = delegate.uri();
+      if (uri.startsWith(scheme + "://")) {
+        // URI is already absolute, only append the path and query
+        uri = delegate.path();
+        if (delegate.query() != null) {
+          uri += "?" + delegate.query();
+        }
+      }
+      absoluteURI = scheme + "://" + host + uri;
     }
   }
 
@@ -188,7 +197,7 @@ private void calculateXForward() {
     }
   }
 
-  private void  setHostAndPort(HostAndPort authority) {
+  private void setHostAndPort(HostAndPort authority) {
     host = authority.host();
     port = authority.port();
   }

vertx-web/src/test/java/io/vertx/ext/web/tests/impl/AbsoluteUriTest.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2023 Red Hat, Inc.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * and Apache License v2.0 which accompanies this distribution.
+ *
+ * The Eclipse Public License is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * The Apache License v2.0 is available at
+ * http://www.opensource.org/licenses/apache2.0.php
+ *
+ * You may elect to redistribute this code under either of these licenses.
+ */
+package io.vertx.ext.web.tests.impl;
+
+import io.netty.handler.codec.http.HttpResponseStatus;
+import io.vertx.core.http.HttpMethod;
+import io.vertx.core.net.HostAndPort;
+import io.vertx.ext.web.tests.WebTestBase;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+import java.util.Arrays;
+
+@RunWith(Parameterized.class)
+public class AbsoluteUriTest extends WebTestBase {
+
+  @Parameterized.Parameters(name = "target={0}, host={1}, query={2}")
+  public static Iterable<Object[]> data() {
+    return Arrays.asList(
+      // absolute URI, no explicit authority, no query -> the authority in the URI is ignored
+      new Object[]{"http://www.example.com:1234/some/path", null, null, "http://localhost:8080/some/path"},
+      // absolute URI, no explicit authority, query present  -> the authority in the URI is ignored
+      new Object[]{"http://www.example.com:1234/some/path", null, "a=1&b=2", "http://localhost:8080/some/path?a=1&b=2"},
+      // absolute URI, same explicit authority, no query
+      new Object[]{"http://www.example.com:1234/some/path", "www.example.com:1234", null, "http://www.example.com:1234/some/path"},
+      // absolute URI, same explicit authority, query present
+      new Object[]{"http://www.example.com:1234/some/path", "www.example.com:1234", "a=1&b=2", "http://www.example.com:1234/some/path?a=1&b=2"},
+      // absolute URI, different explicit authority, no query
+      new Object[]{"http://www.example.com:1234/some/path", "another-host.com:5678", null, "http://another-host.com:5678/some/path"},
+      // absolute URI, different explicit authority, query present
+      new Object[]{"http://www.example.com:1234/some/path", "another-host.com:5678", "a=1&b=2", "http://another-host.com:5678/some/path?a=1&b=2"},
+      // relative URI, no query
+      new Object[]{"/some/path", "www.example.com:1234", null, "http://www.example.com:1234/some/path"},
+      // relative URI, query present
+      new Object[]{"/some/path", "www.example.com:1234", "a=1&b=2", "http://www.example.com:1234/some/path?a=1&b=2"}
+    );
+  }
+
+  private final String target;
+  private final String authority;
+  private final String query;
+  private final String expectedAbsoluteUri;
+
+  public AbsoluteUriTest(String target, String authority, String query, String expectedAbsoluteUri) {
+    this.target = target;
+    this.authority = authority;
+    this.query = query;
+    this.expectedAbsoluteUri = expectedAbsoluteUri;
+  }
+
+  @Test
+  public void testAbsoluteUri() throws Exception {
+    String uri = target + (query != null ? "?" + query : "");
+
+    router.route().handler(event -> {
+      assertEquals(expectedAbsoluteUri, event.request().absoluteURI());
+      assertEquals(uri, event.request().uri());
+      event.response().end();
+    });
+
+    testRequest(HttpMethod.GET, uri, request -> {
+      if (authority != null) {
+        request.authority(HostAndPort.parseAuthority(authority, 80));
+      }
+    }, HttpResponseStatus.OK.code(), HttpResponseStatus.OK.reasonPhrase(), null);
+  }
+}