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WebMvcSseServerTransportProvider: do not include session ID in SSE event #677

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Merged
Kehrlann merged 1 commit into from
Nov 20, 2025
Merged

WebMvcSseServerTransportProvider: do not include session ID in SSE event #677

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76 changes: 29 additions & 47 deletions .../main/java/io/modelcontextprotocol/server/transport/WebMvcSseServerTransportProvider.java
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,6 @@
import java.io.IOException;
import java.time.Duration;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.locks.ReentrantLock;

Expand Down Expand Up @@ -256,39 +255,31 @@ private ServerResponse handleSseConnection(ServerRequest request) {
return ServerResponse.status(HttpStatus.SERVICE_UNAVAILABLE).body("Server is shutting down");
}

String sessionId = UUID.randomUUID().toString();
logger.debug("Creating new SSE connection for session: {}", sessionId);

// Send initial endpoint event
try {
return ServerResponse.sse(sseBuilder -> {
sseBuilder.onComplete(() -> {
logger.debug("SSE connection completed for session: {}", sessionId);
sessions.remove(sessionId);
});
sseBuilder.onTimeout(() -> {
logger.debug("SSE connection timed out for session: {}", sessionId);
sessions.remove(sessionId);
});

WebMvcMcpSessionTransport sessionTransport = new WebMvcMcpSessionTransport(sessionId, sseBuilder);
McpServerSession session = sessionFactory.create(sessionTransport);
this.sessions.put(sessionId, session);
return ServerResponse.sse(sseBuilder -> {
WebMvcMcpSessionTransport sessionTransport = new WebMvcMcpSessionTransport(sseBuilder);
McpServerSession session = sessionFactory.create(sessionTransport);
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@He-Pin He-Pin Nov 19, 2025

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nice to have this.

String sessionId = session.getId();
logger.debug("Creating new SSE connection for session: {}", sessionId);
sseBuilder.onComplete(() -> {
logger.debug("SSE connection completed for session: {}", sessionId);
sessions.remove(sessionId);
});
sseBuilder.onTimeout(() -> {
logger.debug("SSE connection timed out for session: {}", sessionId);
sessions.remove(sessionId);
});
this.sessions.put(sessionId, session);

try {
sseBuilder.id(sessionId).event(ENDPOINT_EVENT_TYPE).data(buildEndpointUrl(sessionId));
}
catch (Exception e) {
logger.error("Failed to send initial endpoint event: {}", e.getMessage());
sseBuilder.error(e);
}
}, Duration.ZERO);
}
catch (Exception e) {
logger.error("Failed to send initial endpoint event to session {}: {}", sessionId, e.getMessage());
sessions.remove(sessionId);
return ServerResponse.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
}
try {
sseBuilder.event(ENDPOINT_EVENT_TYPE).data(buildEndpointUrl(sessionId));
}
catch (Exception e) {
logger.error("Failed to send initial endpoint event: {}", e.getMessage());
this.sessions.remove(sessionId);
sseBuilder.error(e);
}
}, Duration.ZERO);
}

/**
Expand Down Expand Up @@ -363,8 +354,6 @@ private ServerResponse handleMessage(ServerRequest request) {
*/
private class WebMvcMcpSessionTransport implements McpServerTransport {

private final String sessionId;

private final SseBuilder sseBuilder;

/**
Expand All @@ -374,14 +363,11 @@ private class WebMvcMcpSessionTransport implements McpServerTransport {
private final ReentrantLock sseBuilderLock = new ReentrantLock();

/**
* Creates a new session transport with the specified ID and SSE builder.
* @param sessionId The unique identifier for this session
* Creates a new session transport with the specified SSE builder.
* @param sseBuilder The SSE builder for sending server events to the client
*/
WebMvcMcpSessionTransport(String sessionId, SseBuilder sseBuilder) {
this.sessionId = sessionId;
WebMvcMcpSessionTransport(SseBuilder sseBuilder) {
this.sseBuilder = sseBuilder;
logger.debug("Session transport {} initialized with SSE builder", sessionId);
}

/**
Expand All @@ -395,11 +381,10 @@ public Mono<Void> sendMessage(McpSchema.JSONRPCMessage message) {
sseBuilderLock.lock();
try {
String jsonText = jsonMapper.writeValueAsString(message);
sseBuilder.id(sessionId).event(MESSAGE_EVENT_TYPE).data(jsonText);
logger.debug("Message sent to session {}", sessionId);
sseBuilder.event(MESSAGE_EVENT_TYPE).data(jsonText);
}
catch (Exception e) {
logger.error("Failed to send message to session {}: {}", sessionId, e.getMessage());
logger.error("Failed to send message: {}", e.getMessage());
sseBuilder.error(e);
}
finally {
Expand Down Expand Up @@ -427,14 +412,12 @@ public <T> T unmarshalFrom(Object data, TypeRef<T> typeRef) {
@Override
public Mono<Void> closeGracefully() {
return Mono.fromRunnable(() -> {
logger.debug("Closing session transport: {}", sessionId);
sseBuilderLock.lock();
try {
sseBuilder.complete();
logger.debug("Successfully completed SSE builder for session {}", sessionId);
}
catch (Exception e) {
logger.warn("Failed to complete SSE builder for session {}: {}", sessionId, e.getMessage());
logger.warn("Failed to complete SSE builder: {}", e.getMessage());
}
finally {
sseBuilderLock.unlock();
Expand All @@ -450,10 +433,9 @@ public void close() {
sseBuilderLock.lock();
try {
sseBuilder.complete();
logger.debug("Successfully completed SSE builder for session {}", sessionId);
}
catch (Exception e) {
logger.warn("Failed to complete SSE builder for session {}: {}", sessionId, e.getMessage());
logger.warn("Failed to complete SSE builder: {}", e.getMessage());
}
finally {
sseBuilderLock.unlock();
Expand Down