Introduce WebFluxUriComponentsBuilder

This commit introduces the WebFluxUriComponentsBuilder, with a single
method that creates a UriComponentsBuilder for a ServerRequest. More
methods to be added by @rstoyanchev.

Issue: SPR-15953

spring-webflux/src/main/java/org/springframework/web/reactive/support/WebFluxUriComponentsBuilder.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2002-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web.reactive.support;
+
+import java.net.URI;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpRequest;
+import org.springframework.util.Assert;
+import org.springframework.web.reactive.function.server.ServerRequest;
+import org.springframework.web.util.UriComponentsBuilder;
+
+/**
+ * @author Arjen Poutsma
+ * @since 5.0
+ */
+public class WebFluxUriComponentsBuilder {
+
+	/**
+	 * Create a new {@code UriComponents} object from the URI associated with
+	 * the given {@code ServerRequest} while also overlaying with values from the headers
+	 * "Forwarded" (<a href="http://tools.ietf.org/html/rfc7239">RFC 7239</a>),
+	 * or "X-Forwarded-Host", "X-Forwarded-Port", and "X-Forwarded-Proto" if
+	 * "Forwarded" is not found.
+	 * @param request the source request
+	 * @return the URI components of the URI
+	 */
+	public static UriComponentsBuilder fromServerRequest(ServerRequest request) {
+		Assert.notNull(request, "'request' must not be null");
+
+		return UriComponentsBuilder.fromHttpRequest(new ServerRequestAdapter(request));
+	}
+
+
+	private static final class ServerRequestAdapter implements HttpRequest {
+
+		private final ServerRequest adaptee;
+
+		public ServerRequestAdapter(ServerRequest adaptee) {
+			this.adaptee = adaptee;
+		}
+
+		@Override
+		public String getMethodValue() {
+			return this.adaptee.methodName();
+		}
+
+		@Override
+		public URI getURI() {
+			return this.adaptee.uri();
+		}
+
+		@Override
+		public HttpHeaders getHeaders() {
+			return this.adaptee.headers().asHttpHeaders();
+		}
+	}
+
+}

spring-webflux/src/test/java/org/springframework/web/reactive/support/WebFluxUriComponentsBuilderTests.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2002-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web.reactive.support;
+
+import java.net.URI;
+
+import org.junit.Test;
+
+import org.springframework.web.reactive.function.server.MockServerRequest;
+import org.springframework.web.util.UriComponents;
+
+import static org.junit.Assert.*;
+
+/**
+ * @author Arjen Poutsma
+ */
+public class WebFluxUriComponentsBuilderTests {
+
+	@Test
+	public void fromServerRequest() throws Exception {
+		URI uri = new URI("http", "localhost", "/path", "a=1", null);
+		MockServerRequest request = MockServerRequest.builder().uri(uri).build();
+
+		UriComponents result = WebFluxUriComponentsBuilder.fromServerRequest(request).build();
+		assertEquals("http", result.getScheme());
+		assertEquals("localhost", result.getHost());
+		assertEquals(-1, result.getPort());
+		assertEquals("/path", result.getPath());
+		assertEquals("a=1", result.getQuery());
+	}
+
+}