Issue #1116 Allow empty HTTP header value

jetty-http/src/main/java/org/eclipse/jetty/http/HttpGenerator.java

@@ -560,10 +560,6 @@ public class HttpGenerator
         for (int f=0;f<n;f++)
         {
             HttpField field = trailer.getField(f);
-            String v = field.getValue();
-            if (v==null || v.length()==0)
-                continue; // rfc7230 does not allow no value
-
             putTo(field,buffer);
         }
 

jetty-http/src/test/java/org/eclipse/jetty/http/HttpGeneratorClientTest.java

@@ -79,6 +79,47 @@ public class HttpGeneratorClientTest
         Assert.assertThat(out, Matchers.not(Matchers.containsString("Content-Length")));
     }
 
+    @Test
+    public void testEmptyHeaders() throws Exception
+    {
+        ByteBuffer header=BufferUtil.allocate(2048);
+        HttpGenerator gen = new HttpGenerator();
+
+        HttpGenerator.Result
+        result=gen.generateRequest(null,null,null,null, true);
+        Assert.assertEquals(HttpGenerator.Result.NEED_INFO, result);
+        Assert.assertEquals(HttpGenerator.State.START, gen.getState());
+
+        Info info = new Info("GET","/index.html");
+        info.getFields().add("Host","something");
+        info.getFields().add("Null",null);
+        info.getFields().add("Empty","");
+        Assert.assertTrue(!gen.isChunking());
+
+        result=gen.generateRequest(info,null,null,null, true);
+        Assert.assertEquals(HttpGenerator.Result.NEED_HEADER, result);
+        Assert.assertEquals(HttpGenerator.State.START, gen.getState());
+
+        result=gen.generateRequest(info,header,null,null, true);
+        Assert.assertEquals(HttpGenerator.Result.FLUSH, result);
+        Assert.assertEquals(HttpGenerator.State.COMPLETING, gen.getState());
+        Assert.assertTrue(!gen.isChunking());
+        String out = BufferUtil.toString(header);
+        BufferUtil.clear(header);
+
+        result=gen.generateResponse(null,false,null,null, null, false);
+        Assert.assertEquals(HttpGenerator.Result.DONE, result);
+        Assert.assertEquals(HttpGenerator.State.END, gen.getState());
+        Assert.assertTrue(!gen.isChunking());
+
+        Assert.assertEquals(0, gen.getContentPrepared());
+        Assert.assertThat(out, Matchers.containsString("GET /index.html HTTP/1.1"));
+        Assert.assertThat(out, Matchers.not(Matchers.containsString("Content-Length")));
+        Assert.assertThat(out, Matchers.containsString("Empty:"));
+        Assert.assertThat(out, Matchers.not(Matchers.containsString("Null:")));
+    }
+    
+    
     @Test
     public void testPOSTRequestNoContent() throws Exception
     {