Fix request absolute URI handling

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);
+  }
+}