[SignalR] Don't throw for message headers in Java client (#62784)

Co-authored-by: Brennan <[email protected]>

src/SignalR/clients/java/signalr/core/src/main/java/com/microsoft/signalr/GsonHubProtocol.java

@@ -126,7 +126,14 @@ public final class GsonHubProtocol implements HubProtocol {
                             }
                             break;
                         case "headers":
-                            throw new RuntimeException("Headers not implemented yet.");
+                            // Parse headers as Map<String, String> but don't store for now as it's unused
+                            reader.beginObject();
+                            while (reader.hasNext()) {
+                                reader.nextName(); // Read the key
+                                reader.nextString(); // Read the value
+                            }
+                            reader.endObject();
+                            break;
                         default:
                             // Skip unknown property, allows new clients to still work with old protocols
                             reader.skipValue();

src/SignalR/clients/java/signalr/test/src/main/java/com/microsoft/signalr/GsonHubProtocolTest.java

@@ -527,4 +527,98 @@ class GsonHubProtocolTest {
         assertEquals(3, (int) invocationMessage.getArguments()[0]);
         assertEquals("four", invocationMessage.getArguments()[1]);
     }
+
+    @Test
+    public void canParseInvocationMessageWithHeaders() {
+        String stringifiedMessage = "{\"type\":1,\"target\":\"test\",\"arguments\":[42],\"headers\":{\"a\":\"b\",\"c\":\"d\"}}\u001E";
+        ByteBuffer message = TestUtils.stringToByteBuffer(stringifiedMessage);
+        TestBinder binder = new TestBinder(new Type[] { int.class }, null);
+
+        List<HubMessage> messages = hubProtocol.parseMessages(message, binder);
+
+        assertNotNull(messages);
+        assertEquals(1, messages.size());
+
+        assertEquals(HubMessageType.INVOCATION, messages.get(0).getMessageType());
+        InvocationMessage invocationMessage = (InvocationMessage) messages.get(0);
+
+        assertEquals("test", invocationMessage.getTarget());
+        assertEquals(null, invocationMessage.getInvocationId());
+        int messageResult = (int)invocationMessage.getArguments()[0];
+        assertEquals(42, messageResult);
+        // Headers are parsed but not stored, so we just verify the message was processed successfully
+    }
+
+    @Test
+    public void canParseInvocationMessageWithEmptyHeaders() {
+        String stringifiedMessage = "{\"type\":1,\"target\":\"test\",\"arguments\":[42],\"headers\":{}}\u001E";
+        ByteBuffer message = TestUtils.stringToByteBuffer(stringifiedMessage);
+        TestBinder binder = new TestBinder(new Type[] { int.class }, null);
+
+        List<HubMessage> messages = hubProtocol.parseMessages(message, binder);
+
+        assertNotNull(messages);
+        assertEquals(1, messages.size());
+
+        assertEquals(HubMessageType.INVOCATION, messages.get(0).getMessageType());
+        InvocationMessage invocationMessage = (InvocationMessage) messages.get(0);
+
+        assertEquals("test", invocationMessage.getTarget());
+        int messageResult = (int)invocationMessage.getArguments()[0];
+        assertEquals(42, messageResult);
+    }
+
+    @Test
+    public void canParseCompletionMessageWithHeaders() {
+        String stringifiedMessage = "{\"type\":3,\"invocationId\":\"1\",\"result\":42,\"headers\":{\"a\":\"b\",\"c\":\"d\"}}\u001E";
+        ByteBuffer message = TestUtils.stringToByteBuffer(stringifiedMessage);
+        TestBinder binder = new TestBinder(null, int.class);
+
+        List<HubMessage> messages = hubProtocol.parseMessages(message, binder);
+
+        assertNotNull(messages);
+        assertEquals(1, messages.size());
+
+        assertEquals(HubMessageType.COMPLETION, messages.get(0).getMessageType());
+        CompletionMessage completionMessage = (CompletionMessage) messages.get(0);
+        assertEquals("1", completionMessage.getInvocationId());
+        assertEquals(42, completionMessage.getResult());
+        assertEquals(null, completionMessage.getError());
+    }
+
+    @Test
+    public void canParseStreamItemMessageWithHeaders() {
+        String stringifiedMessage = "{\"type\":2,\"invocationId\":\"1\",\"item\":\"test-item\",\"headers\":{\"a\":\"b\"}}\u001E";
+        ByteBuffer message = TestUtils.stringToByteBuffer(stringifiedMessage);
+        TestBinder binder = new TestBinder(null, String.class);
+
+        List<HubMessage> messages = hubProtocol.parseMessages(message, binder);
+
+        assertNotNull(messages);
+        assertEquals(1, messages.size());
+
+        assertEquals(HubMessageType.STREAM_ITEM, messages.get(0).getMessageType());
+        StreamItem streamItem = (StreamItem) messages.get(0);
+        assertEquals("1", streamItem.getInvocationId());
+        assertEquals("test-item", streamItem.getItem());
+    }
+
+    @Test
+    public void canParseMessageWithHeadersInDifferentOrder() {
+        String stringifiedMessage = "{\"headers\":{\"First\":\"value1\",\"Second\":\"value2\"},\"type\":1,\"target\":\"test\",\"arguments\":[42]}\u001E";
+        ByteBuffer message = TestUtils.stringToByteBuffer(stringifiedMessage);
+        TestBinder binder = new TestBinder(new Type[] { int.class }, null);
+
+        List<HubMessage> messages = hubProtocol.parseMessages(message, binder);
+
+        assertNotNull(messages);
+        assertEquals(1, messages.size());
+
+        assertEquals(HubMessageType.INVOCATION, messages.get(0).getMessageType());
+        InvocationMessage invocationMessage = (InvocationMessage) messages.get(0);
+
+        assertEquals("test", invocationMessage.getTarget());
+        int messageResult = (int)invocationMessage.getArguments()[0];
+        assertEquals(42, messageResult);
+    }
 }