Add sftpCommand config option to allow different ways of launching sftp-server

src/connect.ts

@@ -1,6 +1,7 @@
 import { readFile } from 'fs';
 import { Socket } from 'net';
-import { Client, ConnectConfig } from 'ssh2';
+import { Client, ConnectConfig, SFTPWrapper as SFTPWrapperReal } from 'ssh2';
+import { SFTPStream } from 'ssh2-streams';
 import * as vscode from 'vscode';
 import { loadConfigs, openConfigurationEditor } from './config';
 import { FileSystemConfig } from './manager';
@@ -8,6 +9,10 @@ import * as proxy from './proxy';
 import { getSession as getPuttySession } from './putty';
 import { toPromise } from './toPromise';
 
+// tslint:disable-next-line:variable-name
+const SFTPWrapper = require('ssh2/lib/SFTPWrapper') as (new (stream: SFTPStream) => SFTPWrapperReal);
+type SFTPWrapper = SFTPWrapperReal;
+
 function replaceVariables(string?: string) {
   if (typeof string !== 'string') return string;
   return string.replace(/\$\w+/g, key => process.env[key.substr(1)] || '');
@@ -171,3 +176,33 @@ export async function createSSH(config: FileSystemConfig, sock?: NodeJS.Readable
     }
   });
 }
+
+export function getSFTP(client: Client, config: FileSystemConfig): Promise<SFTPWrapper> {
+  return new Promise((resolve, reject) => {
+    if (!config.sftpCommand) {
+      return client.sftp((err, sftp) => {
+        if (err) {
+          client.end();
+          reject(err);
+        }
+        resolve(sftp);
+      });
+    }
+    client.exec(config.sftpCommand, (err, channel) => {
+      if (err) {
+        client.end();
+        return reject(err);
+      }
+      channel.once('close', () => (client.end(), reject()));
+      channel.once('error', () => (client.end(), reject()));
+      try {
+        const sftps = new SFTPStream();
+        channel.pipe(sftps).pipe(channel);
+        const sftp = new SFTPWrapper(sftps);
+        resolve(sftp);
+      } catch (e) {
+        reject(e);
+      }
+    });
+  });
+}

src/manager.ts

@@ -3,9 +3,10 @@ import { readFile } from 'fs';
 import { parse as parseJsonc, ParseError } from 'jsonc-parser';
 import * as path from 'path';
 import { Client, ClientChannel, ConnectConfig } from 'ssh2';
+import { SFTPStream } from 'ssh2-streams';
 import * as vscode from 'vscode';
 import { getConfig, loadConfigs, openConfigurationEditor, updateConfig } from './config';
-import { createSocket, createSSH } from './connect';
+import { createSocket, createSSH, getSFTP } from './connect';
 import SSHFileSystem, { EMPTY_FILE_SYSTEM } from './sshFileSystem';
 import { MemoryDuplex } from './streams';
 import { catchingPromise, toPromise } from './toPromise';
@@ -31,6 +32,7 @@ export interface FileSystemConfig extends ConnectConfig {
   proxy?: ProxyConfig;
   privateKeyPath?: string;
   hop?: string;
+  sftpCommand?: string;
 }
 
 export enum ConfigStatus {
@@ -194,12 +196,7 @@ export class Manager implements vscode.FileSystemProvider, vscode.TreeDataProvid
         }
         root = root.replace(/^~/, home.replace(/\/$/, ''));
       }
-      client.sftp(async (err, sftp) => {
-        if (err) {
-          client.end();
-          return reject(err);
-        }
-        sftp.once('end', () => client.end());
+      const sftp = await getSFTP(client, config);
       const fs = new SSHFileSystem(name, sftp, root, config!);
       try {
         const rootUri = vscode.Uri.parse(`ssh://${name}/`);
@@ -222,7 +219,6 @@ export class Manager implements vscode.FileSystemProvider, vscode.TreeDataProvid
       this.onDidChangeTreeDataEmitter.fire();
       client.once('close', hadError => hadError ? this.commandReconnect(name) : (!fs.closing && this.promptReconnect(name)));
       return resolve(fs);
-      });
     }).catch((e) => {
       this.onDidChangeTreeDataEmitter.fire();
       if (!e) {