🔧 Make session ID optional and fix request ID handling

changelog.md

@@ -215,4 +215,13 @@ Refactored all transports to use context.Context for better control over cancell
 - Updated SSE transport to use context for initialization and event handling
 - Updated stdio transport to use context for command execution and response handling
 - Removed channel-based cancellation in favor of context
-- Added proper context propagation throughout the client API 
+- Added proper context propagation throughout the client API 
+
+## Optional Session ID and Request ID Handling
+
+Made session ID optional in SSE transport by using a default session when none is provided. Also ensured request ID handling follows the MCP specification.
+
+- Made session ID optional in server and client SSE transport
+- Added default session support in server
+- Removed session ID requirement from client
+- Updated request ID handling to follow MCP spec 

pkg/client/client.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/go-go-golems/go-go-mcp/pkg/protocol"
 	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
 )
 
 // Transport represents a client transport mechanism
@@ -70,6 +71,7 @@ func (c *Client) Initialize(ctx context.Context, capabilities protocol.ClientCap
 	}
 	c.setRequestID(request)
 
+	log.Debug().Msgf("Sending initialize request")
 	response, err := c.transport.Send(ctx, request)
 	if err != nil {
 		return fmt.Errorf("failed to send initialize request: %w", err)
@@ -416,13 +418,14 @@ func (c *Client) setRequestID(request *protocol.Request) {
 		return // notifications don't have IDs
 	}
 
-	id := json.RawMessage(fmt.Sprintf("%d", c.nextID))
-	request.ID = id
+	// According to MCP spec, request IDs can be either numbers or strings
+	// We'll use numbers for simplicity and compatibility
+	request.ID = json.RawMessage(fmt.Sprintf("%d", c.nextID))
 	c.nextID++
 
 	c.logger.Debug().
 		Str("method", request.Method).
-		RawJSON("id", id).
+		RawJSON("id", request.ID).
 		Msg("set request ID")
 }
 

pkg/client/sse.go

@@ -13,6 +13,7 @@ import (
 	"github.com/go-go-golems/go-go-mcp/pkg/protocol"
 	"github.com/r3labs/sse/v2"
 	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
 )
 
 // SSETransport implements Transport using Server-Sent Events
@@ -22,7 +23,6 @@ type SSETransport struct {
 	client      *http.Client
 	sseClient   *sse.Client
 	events      chan *sse.Event
-	sessionID   string
 	closeOnce   sync.Once
 	logger      zerolog.Logger
 	initialized bool
@@ -137,24 +137,14 @@ func (t *SSETransport) initializeSSE(ctx context.Context) error {
 	go func() {
 		defer cancel()
 
+		log.Debug().Msgf("Subscribing to SSE")
 		err := t.sseClient.SubscribeWithContext(subCtx, "", func(msg *sse.Event) {
-			// Handle session ID event
-			if string(msg.Event) == "session" {
-				t.mu.Lock()
-				t.sessionID = string(msg.Data)
-				t.initialized = true
-				t.mu.Unlock()
-				t.logger.Debug().Str("sessionID", t.sessionID).Msg("Received session ID")
-				initDone <- nil
-				return
-			}
-
 			t.logger.Debug().
 				Str("event", string(msg.Event)).
 				RawJSON("data", msg.Data).
 				Msg("Received SSE event")
 
-			// Forward other events to the events channel
+			// Forward events to the events channel
 			select {
 			case t.events <- msg:
 				t.logger.Debug().Msg("Forwarded event to channel")
@@ -172,15 +162,7 @@ func (t *SSETransport) initializeSSE(ctx context.Context) error {
 		}
 	}()
 
-	// Wait for initialization or context cancellation
-	select {
-	case err := <-initDone:
-		close(initDone)
-		return err
-	case <-ctx.Done():
-		cancel()
-		return ctx.Err()
-	}
+	return nil
 }
 
 // Close closes the transport

pkg/server/sse.go

@@ -12,7 +12,6 @@ import (
 	"github.com/go-go-golems/go-go-mcp/pkg"
 	"github.com/go-go-golems/go-go-mcp/pkg/protocol"
 	"github.com/go-go-golems/go-go-mcp/pkg/services"
-	"github.com/google/uuid"
 	"github.com/gorilla/mux"
 	"github.com/rs/zerolog"
 )
@@ -123,8 +122,11 @@ func (s *SSEServer) handleSSE(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Connection", "keep-alive")
 	w.Header().Set("Access-Control-Allow-Origin", "*")
 
-	// Create unique session ID
-	sessionID := uuid.New().String()
+	// Create unique session ID or use default
+	sessionID := "default"
+	if r.URL.Query().Get("session_id") != "" {
+		sessionID = r.URL.Query().Get("session_id")
+	}
 	messageChan := make(chan *protocol.Response, 100)
 
 	// Register client
@@ -196,21 +198,19 @@ func (s *SSEServer) handleMessages(w http.ResponseWriter, r *http.Request) {
 		Str("remote_addr", r.RemoteAddr).
 		Msg("Received message request")
 
+	// Use default session if none provided
 	if sessionID == "" {
-		s.logger.Error().Msg("Missing session_id in request")
-		http.Error(w, "session_id is required", http.StatusBadRequest)
-		return
+		sessionID = "default"
+		s.logger.Debug().Msg("Using default session")
 	}
 
 	s.mu.RLock()
-	messageChan, exists := s.clients[sessionID]
+	messageChan, ok := s.clients[sessionID]
 	s.mu.RUnlock()
 
-	if !exists {
-		s.logger.Error().
-			Str("session_id", sessionID).
-			Msg("Session not found")
-		http.Error(w, "session not found", http.StatusNotFound)
+	if !ok {
+		s.logger.Error().Str("session_id", sessionID).Msg("Invalid session_id")
+		http.Error(w, "Invalid session_id", http.StatusBadRequest)
 		return
 	}