WriteStream supports r, r+, w, w+ options.

lib/api/rename.js

@@ -69,4 +69,4 @@ function renameBuffer (newPath) {
 
   ]);
 
-}
\ No newline at end of file
+}

lib/api/src/createWriteStream.js

@@ -3,6 +3,12 @@ import Bluebird from 'bluebird'
 import {request} from '../tools/smb2-forge'
 import {Writable} from 'stream'
 
+import {
+  FILE_OPEN,
+  FILE_OPEN_IF,
+  FILE_OVERWRITE_IF
+} from '../structures/constants'
+
 const requestAsync = Bluebird.promisify(request)
 
 const maxPacketSize = new Bigint(8, 0x00010000 - 0x71)
@@ -86,7 +92,19 @@ export default function (path, options, cb) {
     cb = options
     options = {}
   }
-  request('create', {path}, this, (err, file) => {
+
+  let createDisposition
+  const flags = options && options.flags
+
+  if (flags === 'r') {
+    createDisposition = FILE_OPEN
+  } else if (flags === 'r+') {
+    createDisposition = FILE_OPEN_IF
+  } else if (flags === 'w' || flags === 'w+') {
+    createDisposition = FILE_OVERWRITE_IF
+  }
+
+  request('create', { path, createDisposition }, this, (err, file) => {
     if (err) {
       cb(err)
     } else {

lib/messages/create.js

-
-
 var SMB2Message = require('../tools/smb2-message')
-  , message = require('../tools/message')
-  ;
-
+var message = require('../tools/message')
+var FILE_OVERWRITE_IF = require('../structures/constants').FILE_OVERWRITE_IF
 
 module.exports = message({
 
   generate:function(connection, params){
 
     var buffer = new Buffer(params.path, 'ucs2');
+    var createDisposition = params.createDisposition
+
+    if (!(createDisposition >= 0 && createDisposition <= 5)) {
+      createDisposition = FILE_OVERWRITE_IF
+    }
 
     return new SMB2Message({
       headers:{
@@ -23,7 +25,7 @@ module.exports = message({
       , 'DesiredAccess':0x001701DF
       , 'FileAttributes':0x00000080
       , 'ShareAccess':0x00000000
-      , 'CreateDisposition':0x00000005
+      , 'CreateDisposition': createDisposition
       , 'CreateOptions':0x00000044
       , 'NameOffset':0x0078
       , 'CreateContextsOffset':0x007A+buffer.length

lib/structures/constants.js

+module.exports = {
+  FILE_SUPERSEDE: 0x00000000,
+  FILE_OPEN: 0x00000001,
+  FILE_CREATE: 0x00000002,
+  FILE_OPEN_IF: 0x00000003,
+  FILE_OVERWRITE: 0x00000004,
+  FILE_OVERWRITE_IF: 0x00000005
+}