Backport fix for apache/camel-k-runtime#301 into camel-platform-http-…

…vertx

components/camel-platform-http-vertx/src/main/java/org/apache/camel/component/platform/http/vertx/VertxPlatformHttpSupport.java

@@ -110,6 +110,14 @@ static Object toHttpResponse(HttpServerResponse response, Message message, Heade
             ExchangeHelper.setFailureHandled(exchange);
         }
 
+        // set the content-length if it can be determined, or chunked encoding
+        final Integer length = determineContentLength(exchange, body);
+        if (length != null) {
+            response.putHeader("Content-Length", String.valueOf(length));
+        } else {
+            response.setChunked(true);
+        }
+
         // set the content type in the response.
         final String contentType = MessageHelper.getContentType(message);
         if (contentType != null) {
@@ -119,6 +127,15 @@ static Object toHttpResponse(HttpServerResponse response, Message message, Heade
         return body;
     }
 
+    static Integer determineContentLength(Exchange camelExchange, Object body) {
+        if (body instanceof byte[]) {
+            return ((byte[]) body).length;
+        } else if (body instanceof ByteBuffer) {
+            return ((ByteBuffer) body).remaining();
+        }
+        return null;
+    }
+
     /*
      * Copied from org.apache.camel.http.common.DefaultHttpBinding.determineResponseCode(Exchange, Object)
      * If DefaultHttpBinding.determineResponseCode(Exchange, Object) is moved to a module without the servlet-api