Separate adding X-ForwardedProto header

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/filters/pre/PreDecorationFilter.java

@@ -184,6 +184,8 @@ public class PreDecorationFilter extends ZuulFilter {
 			} else {
 				port = request.getHeader("X-Forwarded-Port") + "," + port;
 			}
+		}
+		if (hasHeader(request, "X-Forwarded-Proto")) {
 			proto = request.getHeader("X-Forwarded-Proto") + "," + proto;
 		}
 		ctx.addZuulRequestHeader("X-Forwarded-Host", host);

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/zuul/filters/pre/PreDecorationFilterTests.java

@@ -104,7 +104,7 @@ public class PreDecorationFilterTests {
 	}
 
 	@Test
-	public void xForwardedHostAppends() throws Exception {
+	public void xForwardedHostAndProtoAppend() throws Exception {
 		this.properties.setPrefix("/api");
 		this.request.setRequestURI("/api/foo/1");
 		this.request.setRemoteAddr("5.6.7.8");
@@ -121,6 +121,39 @@ public class PreDecorationFilterTests {
 	}
 
 	@Test
+	public void xForwardedHostOnlyAppends() throws Exception {
+		this.properties.setPrefix("/api");
+		this.request.setRequestURI("/api/foo/1");
+		this.request.setRemoteAddr("5.6.7.8");
+		this.request.setServerPort(8080);
+		this.request.addHeader("X-Forwarded-Host", "example.com");
+		this.routeLocator.addRoute(
+				new ZuulRoute("foo", "/foo/**", "foo", null, false, null, null));
+		this.filter.run();
+		RequestContext ctx = RequestContext.getCurrentContext();
+		assertEquals("example.com,localhost:8080",
+				ctx.getZuulRequestHeaders().get("x-forwarded-host"));
+		assertEquals("8080", ctx.getZuulRequestHeaders().get("x-forwarded-port"));
+		assertEquals("http", ctx.getZuulRequestHeaders().get("x-forwarded-proto"));
+	}
+
+	@Test
+	public void xForwardedProtoOnlyAppends() throws Exception {
+		this.properties.setPrefix("/api");
+		this.request.setRequestURI("/api/foo/1");
+		this.request.setRemoteAddr("5.6.7.8");
+		this.request.setServerPort(8080);
+		this.request.addHeader("X-Forwarded-Proto", "https");
+		this.routeLocator.addRoute(
+				new ZuulRoute("foo", "/foo/**", "foo", null, false, null, null));
+		this.filter.run();
+		RequestContext ctx = RequestContext.getCurrentContext();
+		assertEquals("localhost:8080", ctx.getZuulRequestHeaders().get("x-forwarded-host"));
+		assertEquals("8080", ctx.getZuulRequestHeaders().get("x-forwarded-port"));
+		assertEquals("https,http", ctx.getZuulRequestHeaders().get("x-forwarded-proto"));
+	}
+
+	@Test
 	public void hostHeaderSet() throws Exception {
 		this.properties.setPrefix("/api");
 		this.properties.setAddHostHeader(true);