fix: use streaming download for large files in file manager

src/backend/ssh/file-manager.ts

@@ -4870,6 +4870,55 @@ app.post("/ssh/file_manager/ssh/downloadFile", async (req, res) => {
     });
 });
 
+app.post("/ssh/file_manager/ssh/downloadFileStream", async (req, res) => {
+  const { sessionId, path: filePath } = req.body;
+  const userId = (req as AuthenticatedRequest).userId;
+
+  if (!sessionId || !filePath) {
+    return res.status(400).json({ error: "Missing download parameters" });
+  }
+
+  const sshConn = sshSessions[sessionId];
+  if (!sshConn?.isConnected) {
+    return res.status(400).json({ error: "SSH session not found or not connected" });
+  }
+  if (!verifySessionOwnership(sshConn, userId)) {
+    return res.status(403).json({ error: "Session access denied" });
+  }
+
+  sshConn.lastActive = Date.now();
+
+  try {
+    const sftp = await getSessionSftp(sshConn);
+    const stats = await new Promise<{ size: number; isFile: () => boolean }>((resolve, reject) => {
+      sftp.stat(filePath, (err, s) => (err ? reject(err) : resolve(s)));
+    });
+
+    if (!stats.isFile()) {
+      return res.status(400).json({ error: "Cannot download directories" });
+    }
+
+    const fileName = filePath.split("/").pop() || "download";
+    res.setHeader("Content-Type", "application/octet-stream");
+    res.setHeader("Content-Disposition", `attachment; filename="${encodeURIComponent(fileName)}"`);
+    res.setHeader("Content-Length", String(stats.size));
+
+    const readStream = sftp.createReadStream(filePath);
+    readStream.on("error", (err) => {
+      if (!res.headersSent) {
+        res.status(500).json({ error: `Download failed: ${err.message}` });
+      } else {
+        res.destroy();
+      }
+    });
+    readStream.pipe(res);
+  } catch (err) {
+    if (!res.headersSent) {
+      res.status(500).json({ error: `Download failed: ${(err as Error).message}` });
+    }
+  }
+});
+
 /**
  * @openapi
  * /ssh/file_manager/ssh/copyItem:

src/ui/features/file-manager/FileManager.tsx

@@ -864,38 +864,12 @@ function FileManagerContent({ initialHost, onClose }: FileManagerProps) {
     try {
       await ensureSSHConnection();
 
-      const response = await downloadSSHFile(sshSessionId, file.path);
+      const { downloadSSHFileStream } = await import("@/main-axios.ts");
+      await downloadSSHFileStream(sshSessionId, file.path);
 
-      const content = response?.content as string | undefined;
+      toast.success(
-      const mimeType = response?.mimeType as string | undefined;
+        t("fileManager.fileDownloadedSuccessfully", { name: file.name }),
-      const fileName = response?.fileName as string | undefined;
+      );
-
-      if (content) {
-        const byteCharacters = atob(content);
-        const byteNumbers = new Array(byteCharacters.length);
-        for (let i = 0; i < byteCharacters.length; i++) {
-          byteNumbers[i] = byteCharacters.charCodeAt(i);
-        }
-        const byteArray = new Uint8Array(byteNumbers);
-        const blob = new Blob([byteArray], {
-          type: mimeType || "application/octet-stream",
-        });
-
-        const url = URL.createObjectURL(blob);
-        const link = document.createElement("a");
-        link.href = url;
-        link.download = fileName || file.name;
-        document.body.appendChild(link);
-        link.click();
-        document.body.removeChild(link);
-        URL.revokeObjectURL(url);
-
-        toast.success(
-          t("fileManager.fileDownloadedSuccessfully", { name: file.name }),
-        );
-      } else {
-        toast.error(t("fileManager.failedToDownloadFile"));
-      }
     } catch (error: unknown) {
       const err = error instanceof Error ? error : null;
       if (

src/ui/main-axios.ts

@@ -2082,6 +2082,25 @@ export async function downloadSSHFile(
   }
 }
 
+export async function downloadSSHFileStream(
+  sessionId: string,
+  filePath: string,
+): Promise<void> {
+  const response = await fileManagerApi.post(
+    "/ssh/downloadFileStream",
+    { sessionId, path: filePath },
+    { responseType: "blob" },
+  );
+  const blob = response.data as Blob;
+  const fileName = filePath.split("/").pop() || "download";
+  const url = URL.createObjectURL(blob);
+  const a = document.createElement("a");
+  a.href = url;
+  a.download = fileName;
+  a.click();
+  URL.revokeObjectURL(url);
+}
+
 export async function createSSHFile(
   sessionId: string,
   path: string,