#257 - Added support for Forwarded and X-Forwarded-Proto headers.

ControllerLinkBuilder now favors the value of the Forwarded and X-Forwarded-Proto header to build the scheme for the link created.

For more information on the Forwarded header, see http://tools.ietf.org/html/rfc7239.

Related issue: #107.

src/main/java/org/springframework/hateoas/mvc/ControllerLinkBuilder.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.hateoas.mvc;
 
+import static org.springframework.util.StringUtils.*;
+
 import java.lang.reflect.Method;
 import java.net.URI;
 
@@ -26,7 +28,6 @@ import org.springframework.hateoas.core.DummyInvocationUtils;
 import org.springframework.hateoas.core.LinkBuilderSupport;
 import org.springframework.hateoas.core.MappingDiscoverer;
 import org.springframework.util.Assert;
-import org.springframework.util.StringUtils;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.context.request.RequestAttributes;
 import org.springframework.web.context.request.RequestContextHolder;
@@ -186,24 +187,29 @@ public class ControllerLinkBuilder extends LinkBuilderSupport<ControllerLinkBuil
 		HttpServletRequest request = getCurrentRequest();
 		ServletUriComponentsBuilder builder = ServletUriComponentsBuilder.fromServletMapping(request);
 
+		ForwardedHeader forwarded = ForwardedHeader.of(request.getHeader(ForwardedHeader.NAME));
+		String proto = hasText(forwarded.getProto()) ? forwarded.getProto() : request.getHeader("X-Forwarded-Proto");
 		String forwardedSsl = request.getHeader("X-Forwarded-Ssl");
 
-		if (StringUtils.hasText(forwardedSsl) && forwardedSsl.equalsIgnoreCase("on")) {
+		if (hasText(proto)) {
+			builder.scheme(proto);
+		} else if (hasText(forwardedSsl) && forwardedSsl.equalsIgnoreCase("on")) {
 			builder.scheme("https");
 		}
 
-		String host = request.getHeader("X-Forwarded-Host");
+		String host = forwarded.getHost();
+		host = hasText(host) ? host : request.getHeader("X-Forwarded-Host");
 
-		if (!StringUtils.hasText(host)) {
+		if (!hasText(host)) {
 			return builder;
 		}
 
-		String[] hosts = StringUtils.commaDelimitedListToStringArray(host);
+		String[] hosts = commaDelimitedListToStringArray(host);
 		String hostToUse = hosts[0];
 
 		if (hostToUse.contains(":")) {
 
-			String[] hostAndPort = StringUtils.split(hostToUse, ":");
+			String[] hostAndPort = split(hostToUse, ":");
 
 			builder.host(hostAndPort[0]);
 			builder.port(Integer.parseInt(hostAndPort[1]));
@@ -215,7 +221,7 @@ public class ControllerLinkBuilder extends LinkBuilderSupport<ControllerLinkBuil
 
 		String port = request.getHeader("X-Forwarded-Port");
 
-		if (StringUtils.hasText(port)) {
+		if (hasText(port)) {
 			builder.port(Integer.parseInt(port));
 		}
 

src/main/java/org/springframework/hateoas/mvc/ForwardedHeader.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2014 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.hateoas.mvc;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * Value object to partially implement the {@literal Forwarded} header defined in RFC 7239.
+ *
+ * @author Oliver Gierke
+ * @see http://tools.ietf.org/html/rfc7239
+ */
+class ForwardedHeader {
+
+	public static String NAME = "Forwarded";
+	private static final ForwardedHeader NO_HEADER = new ForwardedHeader(Collections.<String, String> emptyMap());
+
+	private final Map<String, String> elements;
+
+	private ForwardedHeader(Map<String, String> elements) {
+		this.elements = elements;
+	}
+
+	/**
+	 * Creates a new {@link ForwardedHeader} from the given source.
+	 * 
+	 * @param source can be {@literal null}.
+	 * @return
+	 */
+	public static ForwardedHeader of(String source) {
+
+		if (!StringUtils.hasText(source)) {
+			return NO_HEADER;
+		}
+
+		Map<String, String> elements = new HashMap<String, String>();
+
+		for (String part : source.split(";")) {
+
+			String[] keyValue = part.split("=");
+
+			if (keyValue.length != 2) {
+				continue;
+			}
+
+			elements.put(keyValue[0].trim(), keyValue[1].trim());
+		}
+
+		Assert.notNull(elements, "Forwarded elements must not be null!");
+		Assert.isTrue(!elements.isEmpty(), "At least one forwarded element needs to be present!");
+
+		return new ForwardedHeader(elements);
+	}
+
+	/**
+	 * Returns the value defined for the {@code proto} parameter of the header.
+	 * 
+	 * @return
+	 */
+	public String getProto() {
+		return elements.get("proto");
+	}
+
+	/**
+	 * Returns the value defined for the {@code host} parameter of the header.
+	 * 
+	 * @return
+	 */
+	public String getHost() {
+		return elements.get("host");
+	}
+}