From b7ec3f4ad34d0c4d72fe6b05587d1cb3be75f573 Mon Sep 17 00:00:00 2001
From: Amir Khodak <amir.khodak@gmail.com>
Date: Sun, 7 Jun 2026 02:34:01 +0000
Subject: [PATCH] =?UTF-8?q?v1.0.71:=20SFTP=20connection=20pooling=20?=
 =?UTF-8?q?=E2=80=94=20reuse=20SSH=20session=20across=20all=20operations?=
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Previously every listFiles/uploadFile/downloadFile/deleteFile call created
a fresh SSH connection (connect → auth → use → disconnect). For zahra's
folder with 69 subdirectories, the recursive listing alone made 70 full
SSH handshakes, then one more per downloaded file — causing connection
timeouts and 65 upload/download failures reported as PARTIAL.

Now the provider holds a persistent SSH session and reuses it for all
calls, reconnecting automatically if the connection drops.
---
 .../data/providers/sftp/SftpProvider.kt       | 37 ++++++++++++++-----
 version.properties                            |  4 +-
 2 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/app/src/main/kotlin/com/syncflow/data/providers/sftp/SftpProvider.kt b/app/src/main/kotlin/com/syncflow/data/providers/sftp/SftpProvider.kt
index 853569e..ef0c570 100644
--- a/app/src/main/kotlin/com/syncflow/data/providers/sftp/SftpProvider.kt
+++ b/app/src/main/kotlin/com/syncflow/data/providers/sftp/SftpProvider.kt
@@ -23,19 +23,36 @@ class SftpProvider(private val account: CloudAccount, private val credentialStor
     private val password = creds["password"]?.jsonPrimitive?.content
     private val privateKey = creds["private_key"]?.jsonPrimitive?.content
 
-    private fun <T> withSftp(block: (SFTPClient) -> T): T {
+    // Persistent SSH connection reused across all operations in the provider's lifetime.
+    // Each call to withSftp checks liveness and reconnects if the connection dropped.
+    // This eliminates the per-operation connect/auth/disconnect cycle that caused
+    // 100+ SSH handshakes during a recursive directory listing + file-transfer sync,
+    // leading to connection timeouts on large folder trees (e.g. 69 subdirectories).
+    private var sshClient: SSHClient? = null
+
+    private fun getOrCreateSsh(): SSHClient {
+        val existing = sshClient
+        if (existing != null && existing.isConnected && existing.isAuthenticated) return existing
         val ssh = SSHClient()
         ssh.addHostKeyVerifier(TofuHostKeyVerifier(credentialStore))
         ssh.connect(host, port)
-        try {
-            if (!privateKey.isNullOrBlank()) {
-                ssh.authPublickey(username, ssh.loadKeys(privateKey, null, null))
-            } else {
-                ssh.authPassword(username, password ?: "")
-            }
-            return ssh.newSFTPClient().use(block)
-        } finally {
-            ssh.disconnect()
+        if (!privateKey.isNullOrBlank()) {
+            ssh.authPublickey(username, ssh.loadKeys(privateKey, null, null))
+        } else {
+            ssh.authPassword(username, password ?: "")
+        }
+        sshClient = ssh
+        return ssh
+    }
+
+    private fun <T> withSftp(block: (SFTPClient) -> T): T {
+        return try {
+            getOrCreateSsh().newSFTPClient().use(block)
+        } catch (e: Exception) {
+            // Connection may have gone stale — reset and retry once with a fresh connection.
+            runCatching { sshClient?.disconnect() }
+            sshClient = null
+            getOrCreateSsh().newSFTPClient().use(block)
         }
     }
 
diff --git a/version.properties b/version.properties
index 282f4b2..b1719d3 100644
--- a/version.properties
+++ b/version.properties
@@ -1,2 +1,2 @@
-VERSION_NAME=1.0.70
-VERSION_CODE=70
+VERSION_NAME=1.0.71
+VERSION_CODE=71