From 82be0e13c3e1053ffb5db7072dcab7494a1ca145 Mon Sep 17 00:00:00 2001 From: Christian Tzolov Date: Wed, 1 Oct 2025 17:08:04 +0100 Subject: [PATCH] fix: Handle non-compliant notification responses Ensure warnings are logged for all non-compliant responses to JSON-RPC notifications, including empty responses. Empty responses now display as "[empty]" in log messages for better clarity. Resolves #586 Signed-off-by: Christian Tzolov --- .../client/transport/HttpClientStreamableHttpTransport.java | 5 +++-- .../client/transport/WebClientStreamableHttpTransport.java | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/mcp-core/src/main/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransport.java b/mcp-core/src/main/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransport.java index 854b3f297..f4505c898 100644 --- a/mcp-core/src/main/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransport.java +++ b/mcp-core/src/main/java/io/modelcontextprotocol/client/transport/HttpClientStreamableHttpTransport.java @@ -507,8 +507,9 @@ else if (contentType.contains(TEXT_EVENT_STREAM)) { else if (contentType.contains(APPLICATION_JSON)) { deliveredSink.success(); String data = ((ResponseSubscribers.AggregateResponseEvent) responseEvent).data(); - if (sentMessage instanceof McpSchema.JSONRPCNotification && Utils.hasText(data)) { - logger.warn("Notification: {} received non-compliant response: {}", sentMessage, data); + if (sentMessage instanceof McpSchema.JSONRPCNotification) { + logger.warn("Notification: {} received non-compliant response: {}", sentMessage, + Utils.hasText(data) ? data : "[empty]"); return Mono.empty(); } diff --git a/mcp-spring/mcp-spring-webflux/src/main/java/io/modelcontextprotocol/client/transport/WebClientStreamableHttpTransport.java b/mcp-spring/mcp-spring-webflux/src/main/java/io/modelcontextprotocol/client/transport/WebClientStreamableHttpTransport.java index 860b1958e..f6ce9b4d3 100644 --- a/mcp-spring/mcp-spring-webflux/src/main/java/io/modelcontextprotocol/client/transport/WebClientStreamableHttpTransport.java +++ b/mcp-spring/mcp-spring-webflux/src/main/java/io/modelcontextprotocol/client/transport/WebClientStreamableHttpTransport.java @@ -423,8 +423,9 @@ private Flux directResponseFlux(McpSchema.JSONRPCMessa ClientResponse response) { return response.bodyToMono(String.class).>handle((responseMessage, s) -> { try { - if (sentMessage instanceof McpSchema.JSONRPCNotification && Utils.hasText(responseMessage)) { - logger.warn("Notification: {} received non-compliant response: {}", sentMessage, responseMessage); + if (sentMessage instanceof McpSchema.JSONRPCNotification) { + logger.warn("Notification: {} received non-compliant response: {}", sentMessage, + Utils.hasText(responseMessage) ? responseMessage : "[empty]"); s.complete(); } else {