From e3a978b639d441b35c4f40129fbd82cf425bddc4 Mon Sep 17 00:00:00 2001
From: Vantz Stockwell <vstockwell@predator-mini.local>
Date: Sat, 14 Mar 2026 04:18:29 -0400
Subject: [PATCH] fix(sftp): cache SFTP channel per session to prevent channel
 exhaustion

---
 backend/src/terminal/ssh-connection.service.ts | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/backend/src/terminal/ssh-connection.service.ts b/backend/src/terminal/ssh-connection.service.ts
index 2cb391d..63956a7 100644
--- a/backend/src/terminal/ssh-connection.service.ts
+++ b/backend/src/terminal/ssh-connection.service.ts
@@ -157,6 +157,7 @@ export class SshConnectionService {
       session.stream?.close();
       session.client.end();
       this.sessions.delete(sessionId);
+      this.sftpChannels.delete(sessionId);
 
       // Update connection log with disconnect time
       this.prisma.connectionLog.updateMany({
@@ -170,21 +171,32 @@ export class SshConnectionService {
     return this.sessions.get(sessionId);
   }
 
+  private sftpChannels = new Map<string, any>();
+
   getSftpChannel(sessionId: string): Promise<any> {
     const logger = this.logger;
+    const cached = this.sftpChannels.get(sessionId);
+    if (cached) {
+      return Promise.resolve(cached);
+    }
     return new Promise((resolve, reject) => {
       const session = this.sessions.get(sessionId);
       if (!session) {
         logger.error(`[SFTP] Session ${sessionId} not found in sessions map (${this.sessions.size} active sessions)`);
         return reject(new Error('Session not found'));
       }
-      logger.log(`[SFTP] Requesting SFTP subsystem on session ${sessionId}, client connected: ${(session.client as any)._sock?.readable ?? 'unknown'}`);
+      logger.log(`[SFTP] Requesting SFTP subsystem on session ${sessionId}`);
       session.client.sftp((err, sftp) => {
         if (err) {
           logger.error(`[SFTP] client.sftp() callback error: ${err.message}`);
           return reject(err);
         }
         logger.log(`[SFTP] SFTP subsystem opened successfully for session ${sessionId}`);
+        sftp.on('close', () => {
+          this.sftpChannels.delete(sessionId);
+          logger.log(`[SFTP] Channel closed for session ${sessionId}`);
+        });
+        this.sftpChannels.set(sessionId, sftp);
         resolve(sftp);
       });
     });