JERSEY-2696 fix: client proxy incorrectly resets "Accept" header defined by @produces annotation

Author: patrikbeno

ext/proxy-client/src/main/java/org/glassfish/jersey/client/proxy/WebResourceFactory.java

@@ -87,6 +87,8 @@
  */
 public final class WebResourceFactory implements InvocationHandler {
 
+    static private final String[] EMPTY = {};
+
     private final WebTarget target;
     private final MultivaluedMap<String, Object> headers;
     private final List<Cookie> cookies;
@@ -279,7 +281,7 @@ public Object invoke(final Object proxy, final Method method, final Object[] arg
         if (produces == null) {
             produces = proxyIfc.getAnnotation(Produces.class);
         }
-        final String[] accepts = produces == null ? null : produces.value();
+        final String[] accepts = (produces == null) ? EMPTY : produces.value();
 
         // determine content type
         String contentType = null;
@@ -294,15 +296,9 @@ public Object invoke(final Object proxy, final Method method, final Object[] arg
             }
         }
 
-        Invocation.Builder builder;
-        if (accepts != null) {
-            builder = newTarget.request(accepts);
-        } else {
-            builder = newTarget.request();
-        }
-
-        // apply header params and cookies
-        builder.headers(headers);
+        Invocation.Builder builder = newTarget.request()
+                .headers(headers) // this resets all headers so do this first
+                .accept(accepts); // if @Produces is defined, propagate values into Accept header; empty array is NO-OP
 
         for (final Cookie c : cookies) {
             builder = builder.cookie(c);

ext/proxy-client/src/test/java/org/glassfish/jersey/client/proxy/MyResource.java

@@ -39,6 +39,8 @@
  */
 package org.glassfish.jersey.client.proxy;
 
+import javax.ws.rs.core.HttpHeaders;
+import javax.ws.rs.core.MediaType;
 import java.util.List;
 import java.util.Set;
 import java.util.SortedSet;
@@ -164,4 +166,10 @@ public String postByNameFormSortedSet(SortedSet<String> name) {
     public MySubResourceIfc getSubResource() {
         return new MySubResource();
     }
+
+    @Override
+    public boolean isAcceptHeaderValid(HttpHeaders headers) {
+        List<MediaType> accepts = headers.getAcceptableMediaTypes();
+        return accepts.contains(MediaType.TEXT_PLAIN_TYPE) && accepts.contains(MediaType.TEXT_XML_TYPE);
+    }
 }

ext/proxy-client/src/test/java/org/glassfish/jersey/client/proxy/MyResourceIfc.java

@@ -54,6 +54,8 @@
 import javax.ws.rs.PathParam;
 import javax.ws.rs.Produces;
 import javax.ws.rs.QueryParam;
+import javax.ws.rs.core.Context;
+import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.MediaType;
 
 @Path("myresource")
@@ -175,4 +177,9 @@ public interface MyResourceIfc {
 
     @Path("subresource")
     MySubResourceIfc getSubResource();
+
+    @Path("isAcceptHeaderValid")
+    @GET
+    @Produces({MediaType.TEXT_PLAIN, MediaType.TEXT_XML})
+    boolean isAcceptHeaderValid(@Context HttpHeaders headers);
 }