Merge pull request #49 from QuantGeekDev/feature/resumability

QuantGeekDev · web-flow · commit 4b47edb24328 · 2025-03-29T02:11:19.000+01:00
feat: add sse resumability
diff --git a/.gitignore b/.gitignore
@@ -5,3 +5,4 @@ README
 .DS_Store
 dist
 node_modules
+.cursor
diff --git a/src/transports/http/server.ts b/src/transports/http/server.ts
@@ -7,7 +7,8 @@ import {
     JsonRpcSuccessResponse,
     JsonRpcErrorResponse,
     JsonRpcError,
-    JsonRpcId 
+    JsonRpcId,
+    MessageEntry
 } from "./types.js";
 
 import contentType from "content-type";
@@ -68,6 +69,8 @@ export class HttpStreamTransport extends AbstractTransport {
   private _requestStreamMap = new Map<string | number, ActiveSseConnection>();
   private _pendingBatches = new Map<ServerResponse, BatchResponseState>();
   private _eventCounter = 0;
+  private _globalMessageStore = new Map<string, Map<string, MessageEntry>>();
+  private _pruneInterval?: NodeJS.Timeout;
 
   constructor(config: HttpStreamTransportConfig = {}) {
     super();
@@ -91,9 +94,14 @@ export class HttpStreamTransport extends AbstractTransport {
       responseMode: this._config.responseMode,
       sessionEnabled: this._config.session.enabled, 
       resumabilityEnabled: this._config.resumability.enabled,
+      resumabilityStore: this._config.resumability.messageStoreType,
       authEnabled: !!this._config.auth, 
       corsOrigin: this._config.cors.allowOrigin
     }, null, 2)}`);
+
+    if (this._config.resumability.enabled && this._config.resumability.messageStoreType === 'global') {
+      this._pruneInterval = setInterval(() => this.pruneMessageStore(), this._config.resumability.historyDuration / 3);
+    }
   }
 
   private getCorsHeaders(req: IncomingMessage, includeMaxAge: boolean = false): Record<string, string> {
@@ -419,7 +427,7 @@ export class HttpStreamTransport extends AbstractTransport {
     const streamId = randomUUID();
     const connection: ActiveSseConnection = {
         res, sessionId, streamId, lastEventIdSent: null,
-        messageHistory: this._config.resumability.enabled ? [] : undefined, 
+        messageHistory: this._config.resumability.enabled && this._config.resumability.messageStoreType === 'connection' ? [] : undefined, 
         pingInterval: undefined,
         isPostConnection
     };
@@ -438,7 +446,7 @@ export class HttpStreamTransport extends AbstractTransport {
     res.write(': stream opened\n\n');
     connection.pingInterval = setInterval(() => this.sendPing(connection), 15000);
     if (lastEventId && this._config.resumability.enabled) {
-        this.handleResumption(connection, lastEventId).catch(err => { logger.error(`Error during stream resumption for ${streamId}: ${err.message}`); this.cleanupConnection(connection, `Resumption error: ${err.message}`); });
+        this.handleResumption(connection, lastEventId, sessionId).catch(err => { logger.error(`Error during stream resumption for ${streamId}: ${err.message}`); this.cleanupConnection(connection, `Resumption error: ${err.message}`); });
     }
     const cleanupHandler = (reason: string) => { if (connection.pingInterval) { clearInterval(connection.pingInterval); connection.pingInterval = undefined; } this.cleanupConnection(connection, reason); };
     res.on("close", () => cleanupHandler("Client closed connection"));
@@ -572,12 +580,16 @@ export class HttpStreamTransport extends AbstractTransport {
         if (this._config.resumability.enabled) {
             eventId = `${Date.now()}-${this._eventCounter++}`;
             targetConnection.lastEventIdSent = eventId;
-            if (targetConnection.messageHistory) {
+            
+            this.storeMessage(message, targetConnection.sessionId, eventId);
+            
+            if (this._config.resumability.messageStoreType === 'connection' && targetConnection.messageHistory) {
                 const timestamp = Date.now();
                 targetConnection.messageHistory.push({ eventId, message, timestamp });
                 const cutoff = timestamp - this._config.resumability.historyDuration;
                 targetConnection.messageHistory = targetConnection.messageHistory.filter(entry => entry.timestamp >= cutoff);
             }
+            
             logger.debug(`Sending SSE event ID: ${eventId} on stream ${targetConnection.streamId}`);
             targetConnection.res.write(`id: ${eventId}\n`);
         }
@@ -641,24 +653,64 @@ export class HttpStreamTransport extends AbstractTransport {
     return session;
   }
 
-  private async handleResumption(connection: ActiveSseConnection, lastEventId: string): Promise<void> {
+  private async handleResumption(connection: ActiveSseConnection, lastEventId: string, sessionId?: string): Promise<void> {
       logger.info(`Attempting resume stream ${connection.streamId} from event ${lastEventId}`);
-      if (!connection.messageHistory || !this._config.resumability.enabled) { logger.warn(`Resume requested for ${connection.streamId}, but history unavailable/disabled. Starting fresh.`); return; }
-      const history = connection.messageHistory;
-      const lastReceivedIndex = history.findIndex(entry => entry.eventId === lastEventId);
-      if (lastReceivedIndex === -1) { logger.warn(`Event ${lastEventId} not found in history for ${connection.streamId}. Starting fresh.`); return; }
-      const messagesToReplay = history.slice(lastReceivedIndex + 1);
-      if (messagesToReplay.length === 0) { logger.info(`Event ${lastEventId} was last known event for ${connection.streamId}. No replay needed.`); return; }
+      
+      let messagesToReplay: MessageEntry[] = [];
+      
+      if (this._config.resumability.messageStoreType === 'global') {
+        if (!this._config.resumability.enabled) {
+          logger.warn(`Resume requested for ${connection.streamId}, but resumability is disabled. Starting fresh.`);
+          return;
+        }
+        
+        messagesToReplay = this.getMessagesAfterEvent(sessionId, lastEventId);
+        
+        if (messagesToReplay.length === 0) {
+          logger.warn(`Event ${lastEventId} not found in global message store for session ${sessionId || 'N/A'}. Starting fresh.`);
+          return;
+        }
+      } else if (this._config.resumability.messageStoreType === 'connection') {
+        if (!connection.messageHistory || !this._config.resumability.enabled) { 
+          logger.warn(`Resume requested for ${connection.streamId}, but history unavailable/disabled. Starting fresh.`); 
+          return; 
+        }
+        
+        const history = connection.messageHistory;
+        const lastReceivedIndex = history.findIndex(entry => entry.eventId === lastEventId);
+        
+        if (lastReceivedIndex === -1) { 
+          logger.warn(`Event ${lastEventId} not found in history for ${connection.streamId}. Starting fresh.`); 
+          return; 
+        }
+        
+        messagesToReplay = history.slice(lastReceivedIndex + 1);
+      }
+      
+      if (messagesToReplay.length === 0) { 
+        logger.info(`Event ${lastEventId} was last known event for ${connection.streamId}. No replay needed.`); 
+        return; 
+      }
+      
       logger.info(`Replaying ${messagesToReplay.length} messages for stream ${connection.streamId}`);
+      
       for (const entry of messagesToReplay) {
-           if (!connection.res || connection.res.writableEnded) { logger.warn(`Stream ${connection.streamId} closed during replay. Aborting.`); return; }
+           if (!connection.res || connection.res.writableEnded) { 
+             logger.warn(`Stream ${connection.streamId} closed during replay. Aborting.`); 
+             return; 
+           }
            try {
                logger.debug(`Replaying event ${entry.eventId}`);
                connection.res.write(`id: ${entry.eventId}\n`);
                connection.res.write(`data: ${JSON.stringify(entry.message)}\n\n`);
                connection.lastEventIdSent = entry.eventId;
-           } catch(error: any) { logger.error(`Error replaying message ${entry.eventId} to ${connection.streamId}: ${error.message}. Aborting.`); this.cleanupConnection(connection, `Replay write error: ${error.message}`); return; }
+           } catch(error: any) { 
+             logger.error(`Error replaying message ${entry.eventId} to ${connection.streamId}: ${error.message}. Aborting.`); 
+             this.cleanupConnection(connection, `Replay write error: ${error.message}`); 
+             return; 
+           }
       }
+      
       logger.info(`Finished replaying messages for stream ${connection.streamId}`);
   }
 
@@ -699,7 +751,14 @@ export class HttpStreamTransport extends AbstractTransport {
 
   async close(): Promise<void> {
     logger.info("Closing HttpStreamTransport...");
+    
+    if (this._pruneInterval) {
+      clearInterval(this._pruneInterval);
+      this._pruneInterval = undefined;
+    }
+
     this.cleanupAllConnections();
+    
     return new Promise((resolve, reject) => {
       if (this._server) {
         const server = this._server; this._server = undefined;
@@ -709,4 +768,61 @@ export class HttpStreamTransport extends AbstractTransport {
     });
   }
   isRunning(): boolean { return Boolean(this._server?.listening); }
+
+  private storeMessage(message: JsonRpcMessage, sessionId: string | undefined, eventId: string): void {
+    if (!this._config.resumability.enabled) return;
+
+    const timestamp = Date.now();
+    const messageEntry: MessageEntry = { eventId, message, timestamp };
+
+    if (this._config.resumability.messageStoreType === 'global' && sessionId) {
+      if (!this._globalMessageStore.has(sessionId)) {
+        this._globalMessageStore.set(sessionId, new Map());
+      }
+      this._globalMessageStore.get(sessionId)!.set(eventId, messageEntry);
+    }
+  }
+
+  private pruneMessageStore(): void {
+    if (!this._config.resumability.enabled || this._config.resumability.messageStoreType !== 'global') return;
+
+    const cutoff = Date.now() - this._config.resumability.historyDuration;
+    
+    for (const [sessionId, messages] of this._globalMessageStore.entries()) {
+      let expired = 0;
+      for (const [eventId, entry] of messages.entries()) {
+        if (entry.timestamp < cutoff) {
+          messages.delete(eventId);
+          expired++;
+        }
+      }
+      
+      if (messages.size === 0) {
+        this._globalMessageStore.delete(sessionId);
+      } else if (expired > 0) {
+        logger.debug(`Pruned ${expired} expired messages for session ${sessionId}`);
+      }
+    }
+  }
+
+  private getMessagesAfterEvent(sessionId: string | undefined, lastEventId: string): MessageEntry[] {
+    if (!sessionId || !this._config.resumability.enabled || 
+        this._config.resumability.messageStoreType !== 'global' ||
+        !this._globalMessageStore.has(sessionId)) {
+      return [];
+    }
+
+    const messages = this._globalMessageStore.get(sessionId)!;
+    
+    const allEntries = Array.from(messages.values())
+      .sort((a, b) => a.timestamp - b.timestamp);
+
+    const lastReceivedIndex = allEntries.findIndex(entry => entry.eventId === lastEventId);
+    
+    if (lastReceivedIndex === -1) {
+      return [];
+    }
+    
+    return allEntries.slice(lastReceivedIndex + 1);
+  }
 }
diff --git a/src/transports/http/types.ts b/src/transports/http/types.ts
@@ -139,6 +139,7 @@ export interface HttpStreamTransportConfig {
      * How long to keep message history in ms. Default: 300000 (5 min)
      */
     historyDuration?: number;
+    messageStoreType?: 'connection' | 'global';
   };
 }
 
@@ -170,6 +171,7 @@ export const DEFAULT_HTTP_STREAM_CONFIG: HttpStreamTransportConfigInternal = {
   resumability: {
     enabled: false,
     historyDuration: 300000,
+    messageStoreType: 'global',
   },
   cors: {
     allowOrigin: "*",
@@ -197,7 +199,7 @@ export interface ActiveSseConnection {
   sessionId?: string;
   streamId: string;
   lastEventIdSent: string | null;
-  messageHistory?: Array<{ eventId: string; message: JsonRpcMessage; timestamp: number }>;
+  messageHistory?: Array<MessageEntry>;
   pingInterval?: NodeJS.Timeout;
   isPostConnection: boolean;
   pendingResponseIds?: Set<string | number>;
@@ -213,3 +215,9 @@ export interface BatchResponseState {
     timeoutId: NodeJS.Timeout;
     isCompleted: boolean;
 }
+
+export interface MessageEntry {
+  eventId: string;
+  message: JsonRpcMessage;
+  timestamp: number;
+}
