Hosting WSH (VBScript, JavaScript) in your delphi application?

Question

I'm looking to execute user supplied scripts from my Delphi application.

Is it possible to host the Windows Script Host engine in my application and supply it with scripts to execute? Or, is there a better way to approach this problem?

P.S I'm not looking for third-party components.

Mattern

See also stackoverflow.com/questions/226135/scripting-library-for-delphi which links to many scripting engines available in Delphi. – Dodecahedron

You cannot host WSH as WSH is a program that hosts the VBS or JS scripting engines. You have to host those engines yourself, which is easy. As the root wscript object is an application object it is not available in scripts run outside of WSH. However all the utility sub objects are available via CreateObject. – Maloney

Answer 1

This is entirely possible and there is plenty of code out there that shows how to do this. Check out: http://www.torry.net/pages.php?id=280

Intimate

Are any of those free? With source? What about hosting the engine directly without any third-party components? – Mattern

On Torry, any item that is marked with "FWS" means "Freeware with source". A bunch of those packages are marked that way. Some of them look they are all Pascal so the engine is compiled into your app. Others seem to make use of external engines like Lua. – Illfavored

Answer 2

Allen Bauer made a blog post about using Active Scripting a few years back. It goes into the theory behind it and links to code on Code Central which supports VBScript and JavaScript, no third party components necessary.

Stitch

Answer 3

Here is a complete code sample which I converted from this C++ question:

How to load & call a VBScript function from within C++?

You need the IActiveScript, etc. interfaces which are defined like this:

unit AscrLib;

// PASTLWTR : 1.1
// File generated on 7/27/00 12:13:00 PM from Type Library described below.

// ************************************************************************ //
// Type Lib: E:\tp\internet\temp.tlb (1)
// IID\LCID: {B1376415-E2EF-11D1-A693-00AA00125A98}\0
// Helpfile:
// DepndLst:
//   (1) v2.0 stdole, (C:\WINNT\System32\STDOLE2.TLB)
//   (2) v4.0 StdVCL, (z:\Iliad\Bin\STDVCL40.DLL)
// ************************************************************************ //

{$TYPEDADDRESS OFF} // Unit must be compiled without type-checked pointers.
interface

uses Windows, ActiveX, Classes, StdVCL;

// *********************************************************************//
// GUIDS declared in the TypeLibrary. Following prefixes are used:
//   Type Libraries     : LIBID_xxxx
//   CoClasses          : CLASS_xxxx
//   DISPInterfaces     : DIID_xxxx
//   Non-DISP interfaces: IID_xxxx
// *********************************************************************//
const
  // TypeLibrary Major and minor versions
  ActiveScriptLibMajorVersion = 1;
  ActiveScriptLibMinorVersion = 0;

  LIBID_ActiveScriptLib: TGUID = '{B1376415-E2EF-11D1-A693-00AA00125A98}';

  IID_IActiveScript: TGUID = '{BB1A2AE1-A4F9-11CF-8F20-00805F2CD064}';
  IID_IActiveScriptSite: TGUID = '{DB01A1E3-A42B-11CF-8F20-00805F2CD064}';
  IID_IActiveScriptError: TGUID = '{EAE1BA61-A4ED-11CF-8F20-00805F2CD064}';
  IID_IActiveScriptParse: TGUID = '{BB1A2AE2-A4F9-11CF-8F20-00805F2CD064}';
  IID_IActiveScriptSiteWindow: TGUID = '{D10F6761-83E9-11CF-8F20-00805F2CD064}';

// *********************************************************************//
// Declaration of Enumerations defined in Type Library
// *********************************************************************//
// Constants for enum tagSCRIPTSTATE
type
  tagSCRIPTSTATE = TOleEnum;
const
  SCRIPTSTATE_UNINITIALIZED = $00000000;
  SCRIPTSTATE_INITIALIZED = $00000005;
  SCRIPTSTATE_STARTED = $00000001;
  SCRIPTSTATE_CONNECTED = $00000002;
  SCRIPTSTATE_DISCONNECTED = $00000003;
  SCRIPTSTATE_CLOSED = $00000004;

// Constants for enum tagSCRIPTTHREADSTATE
type
  tagSCRIPTTHREADSTATE = TOleEnum;
const
  SCRIPTTHREADSTATE_NOTINSCRIPT = $00000000;
  SCRIPTTHREADSTATE_RUNNING = $00000001;

// Constants for enum tagSCRIPTINFO
type
  tagSCRIPTINFO = TOleEnum;
const
  SCRIPTINFO_IUNKNOWN = $00000001;
  SCRIPTINFO_ITYPEINFO = $00000002;

// Constants for enum tagSCRIPTITEM
type
  tagSCRIPTITEM = TOleEnum;
const
  SCRIPTITEM_ISVISIBLE = $00000002;
  SCRIPTITEM_ISSOURCE = $00000004;
  SCRIPTITEM_GLOBALMEMBERS = $00000008;
  SCRIPTITEM_ISPERSISTENT = $00000040;
  SCRIPTITEM_CODEONLY = $00000200;
  SCRIPTITEM_NOCODE = $00000400;

type

// *********************************************************************//
// Forward declaration of types defined in TypeLibrary
// *********************************************************************//
  IActiveScript = interface;
  IActiveScriptSite = interface;
  IActiveScriptError = interface;
  IActiveScriptParse = interface;
  IActiveScriptSiteWindow = interface;

// *********************************************************************//
// Declaration of structures, unions and aliases.
// *********************************************************************//
  // wireHWND = ^Integer;
  wireHWND = hWnd;


// *********************************************************************//
// Interface: IActiveScript
// Flags:     (0)
// GUID:      {BB1A2AE1-A4F9-11CF-8F20-00805F2CD064}
// *********************************************************************//
  IActiveScript = interface(IUnknown)
    ['{BB1A2AE1-A4F9-11CF-8F20-00805F2CD064}']
    function  SetScriptSite {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_29:1}const pass: IActiveScriptSite): HResult; stdcall;
    function  GetScriptSite {Flags(1), (2/2) CC:4, INV:1, DBG:6}({VT_29:1}var riid: TGUID;
                                                                 {VT_24:2}out ppvObject: Pointer): HResult; stdcall;
    function  SetScriptState {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_29:0}ss: tagSCRIPTSTATE): HResult; stdcall;
    function  GetScriptState {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_29:1}out pssState: tagSCRIPTSTATE): HResult; stdcall;
    function  Close {Flags(1), (0/0) CC:4, INV:1, DBG:6}: HResult; stdcall;
    function  AddNamedItem {Flags(1), (2/2) CC:4, INV:1, DBG:6}({VT_31:0}pstrName: PWideChar;
                                                                {VT_19:0}dwFlags: LongWord): HResult; stdcall;
    function  AddTypeLib {Flags(1), (4/4) CC:4, INV:1, DBG:6}({VT_29:1}var rguidTypeLib: TGUID;
                                                              {VT_19:0}dwMajor: LongWord;
                                                              {VT_19:0}dwMinor: LongWord;
                                                              {VT_19:0}dwFlags: LongWord): HResult; stdcall;
    function  GetScriptDispatch {Flags(1), (2/2) CC:4, INV:1, DBG:6}({VT_31:0}pstrItemName: PWideChar;
                                                                     {VT_9:1}out ppdisp: IDispatch): HResult; stdcall;
    function  GetCurrentScriptThreadID {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_19:1}out pstidThread: LongWord): HResult; stdcall;
    function  GetScriptThreadID {Flags(1), (2/2) CC:4, INV:1, DBG:6}({VT_19:0}dwWin32ThreadId: LongWord;
                                                                     {VT_19:1}out pstidThread: LongWord): HResult; stdcall;
    function  GetScriptThreadState {Flags(1), (2/2) CC:4, INV:1, DBG:6}({VT_19:0}stidThread: LongWord;
                                                                        {VT_29:1}out pstsState: tagSCRIPTTHREADSTATE): HResult; stdcall;
    function  InterruptScriptThread {Flags(1), (3/3) CC:4, INV:1, DBG:6}({VT_19:0}stidThread: LongWord;
                                                                         {VT_29:1}var pexcepinfo: EXCEPINFO;
                                                                         {VT_19:0}dwFlags: LongWord): HResult; stdcall;
    function  Clone {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_29:2}out ppscript: IActiveScript): HResult; stdcall;
  end;

// *********************************************************************//
// Interface: IActiveScriptSite
// Flags:     (0)
// GUID:      {DB01A1E3-A42B-11CF-8F20-00805F2CD064}
// *********************************************************************//
  IActiveScriptSite = interface(IUnknown)
    ['{DB01A1E3-A42B-11CF-8F20-00805F2CD064}']
    function  GetLCID {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_19:1}out plcid: LongWord): HResult; stdcall;
    function  GetItemInfo {Flags(1), (4/4) CC:4, INV:1, DBG:6}({VT_31:0}pstrName: PWideChar;
                                                               {VT_19:0}dwReturnMask: LongWord;
                                                               {VT_13:1}out ppiunkItem: IUnknown;
                                                               {VT_29:2}out ppti: IUnknown): HResult; stdcall;
    function  GetDocVersionString {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_8:1}out pbstrVersion: WideString): HResult; stdcall;
    function  OnScriptTerminate {Flags(1), (2/2) CC:4, INV:1, DBG:6}({VT_12:1}var pvarResult: OleVariant;
                                                                     {VT_3:1}var pexcepinfo: EXCEPINFO): HResult; stdcall;
    function  OnStateChange {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_29:0}ssScriptState: tagSCRIPTSTATE): HResult; stdcall;
    function  OnScriptError {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_29:1}const pscripterror: IActiveScriptError): HResult; stdcall;
    function  OnEnterScript {Flags(1), (0/0) CC:4, INV:1, DBG:6}: HResult; stdcall;
    function  OnLeaveScript {Flags(1), (0/0) CC:4, INV:1, DBG:6}: HResult; stdcall;
  end;

// *********************************************************************//
// Interface: IActiveScriptError
// Flags:     (0)
// GUID:      {EAE1BA61-A4ED-11CF-8F20-00805F2CD064}
// *********************************************************************//
  IActiveScriptError = interface(IUnknown)
    ['{EAE1BA61-A4ED-11CF-8F20-00805F2CD064}']
    function  GetExceptionInfo {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_24:1}out pexcepinfo: EXCEPINFO): HResult; stdcall;
    function  GetSourcePosition {Flags(1), (3/3) CC:4, INV:1, DBG:6}({VT_19:1}out pdwSourceContext: LongWord;
                                                                     {VT_19:1}out pulLineNumber: LongWord;
                                                                     {VT_3:1}out plCharacterPosition: Integer): HResult; stdcall;
    function  GetSourceLineText {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_8:1}out pbstrSourceLine: WideString): HResult; stdcall;
  end;

// *********************************************************************//
// Interface: IActiveScriptParse
// Flags:     (0)
// GUID:      {BB1A2AE2-A4F9-11CF-8F20-00805F2CD064}
// *********************************************************************//
  IActiveScriptParse = interface(IUnknown)
    ['{BB1A2AE2-A4F9-11CF-8F20-00805F2CD064}']
    function  InitNew {Flags(1), (0/0) CC:4, INV:1, DBG:6}: HResult; stdcall;
    function  AddScriptlet {Flags(1), (11/11) CC:4, INV:1, DBG:6}({VT_31:0}pstrDefaultName: PWideChar;
                                                                  {VT_31:0}pstrCode: PWideChar;
                                                                  {VT_31:0}pstrItemName: PWideChar;
                                                                  {VT_31:0}pstrSubItemName: PWideChar;
                                                                  {VT_31:0}pstrEventName: PWideChar;
                                                                  {VT_31:0}pstrDelimiter: PWideChar;
                                                                  {VT_19:0}dwSourceContextCookie: LongWord;
                                                                  {VT_19:0}ulStartingLineNumber: LongWord;
                                                                  {VT_19:0}dwFlags: LongWord;
                                                                  {VT_8:1}out pBstrName: WideString;
                                                                  {VT_29:1}out pexcepinfo: TGUID): HResult; stdcall;
    function  ParseScriptText {Flags(1), (9/9) CC:4, INV:1, DBG:6}({VT_31:0}pstrCode: PWideChar;
                                                                   {VT_31:0}pstrItemName: PWideChar;
                                                                   {VT_13:0}const punkContext: IUnknown;
                                                                   {VT_31:0}pstrDelimiter: PWideChar;
                                                                   {VT_19:0}dwSourceContextCookie: LongWord;
                                                                   {VT_19:0}ulStartingLineNumber: LongWord;
                                                                   {VT_19:0}dwFlags: LongWord;
                                                                   {VT_12:1}pvarResult: Pointer;
                                                                   {VT_29:1}out pexcepinfo: EXCEPINFO): HResult; stdcall;
  end;

// *********************************************************************//
// Interface: IActiveScriptSiteWindow
// Flags:     (0)
// GUID:      {D10F6761-83E9-11CF-8F20-00805F2CD064}
// *********************************************************************//
  IActiveScriptSiteWindow = interface(IUnknown)
    ['{D10F6761-83E9-11CF-8F20-00805F2CD064}']
    function  GetWindow {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_3:2}out phwnd: wireHWND): HResult; stdcall;
    function  EnableModeless {Flags(1), (1/1) CC:4, INV:1, DBG:6}({VT_3:0}fEnable: Integer): HResult; stdcall;
  end;

implementation

uses ComObj;

end.

Here is the converted example code:

unit Unit2;

interface

uses
  Winapi.ActiveX,
  Winapi.Windows,
  System.ObjAuto,
  AscrLib;

const
  CLSID_VBScript: TGUID = '{b54f3741-5b07-11cf-a4b0-00aa004a55e8}';
  CLSID_JScript: TGUID = '{f414c260-6ac0-11cf-b6d1-00aa00bbbb58}';
  SCRIPT_E_REPORTED = HRESULT($80020101);

type
  TSimpleScriptSite = class(TInterfacedObject, IActiveScriptSite,
    IActiveScriptSiteWindow)
  private
    FHwnd: wireHWND;
  public
    // IActiveScriptSite
    function GetLCID(out plcid: LongWord): HResult; stdcall;
    function GetItemInfo(pstrName: PWideChar; dwReturnMask: LongWord;
      out ppiunkItem: IUnknown; out ppti: IUnknown): HResult; stdcall;
    function GetDocVersionString(out pbstrVersion: WideString)
      : HResult; stdcall;
    function OnScriptTerminate(var pvarResult: OleVariant;
      var pexcepinfo: EXCEPINFO): HResult; stdcall;
    function OnStateChange(ssScriptState: tagSCRIPTSTATE): HResult; stdcall;
    function OnScriptError(const pscripterror: IActiveScriptError)
      : HResult; stdcall;
    function OnEnterScript: HResult; stdcall;
    function OnLeaveScript: HResult; stdcall;
    // IActiveScriptSiteWindow
    function GetWindow(out phwnd: wireHWND): HResult; stdcall;
    function EnableModeless(fEnable: Integer): HResult; stdcall;
  end;

procedure TestActiveScriptingOuter;
procedure TestActiveScripting;

implementation

{ TSimpleScriptSite }

function TSimpleScriptSite.EnableModeless(fEnable: Integer): HResult;
begin
  Result := S_OK;
end;

function TSimpleScriptSite.GetDocVersionString(out pbstrVersion
  : WideString): HResult;
begin
  pbstrVersion := '1.0';
  Result := S_OK;
end;

function TSimpleScriptSite.GetItemInfo(pstrName: PWideChar;
  dwReturnMask: LongWord; out ppiunkItem, ppti: IInterface): HResult;
begin
  Result := TYPE_E_ELEMENTNOTFOUND;
end;

function TSimpleScriptSite.GetLCID(out plcid: LongWord): HResult;
begin
  plcid := 0;
  Result := S_OK;
end;

function TSimpleScriptSite.GetWindow(out phwnd: wireHWND): HResult;
begin
  phwnd := FHwnd;
  Result := S_OK;
end;

function TSimpleScriptSite.OnEnterScript: HResult;
begin
  Result := S_OK;
end;

function TSimpleScriptSite.OnLeaveScript: HResult;
begin
  Result := S_OK;
end;

function TSimpleScriptSite.OnScriptError(const pscripterror
  : IActiveScriptError): HResult;
begin
  Result := S_OK;
end;

function TSimpleScriptSite.OnScriptTerminate(var pvarResult: OleVariant;
  var pexcepinfo: EXCEPINFO): HResult;
begin
  Result := S_OK;
end;

function TSimpleScriptSite.OnStateChange(ssScriptState: tagSCRIPTSTATE)
  : HResult;
begin
  Result := S_OK;
end;

procedure TestActiveScriptingOuter;
var
  hr: HResult;
begin
  hr := CoInitializeEx(nil, COINIT_APARTMENTTHREADED);
  TestActiveScripting;
  CoUninitialize();
end;

procedure TestActiveScripting;
const
  SCRIPTTEXT_ISEXPRESSION = $00000020;
var
  hr: HResult;
  ScriptSite: IActiveScriptSite;
  JScript: IActiveScript;
  JScriptParse: IActiveScriptParse;
  VBScript: IActiveScript;
  VBScriptParse: IActiveScriptParse;
  res: Variant;
  ei: TExcepInfo;
begin
  // Initialize
  ScriptSite := TSimpleScriptSite.Create as IActiveScriptSite;
  hr := CoCreateInstance(CLSID_JScript, nil, CLSCTX_INPROC_SERVER, IID_IActiveScript, JScript);
  hr := JScript.SetScriptSite(ScriptSite);
  JScriptParse := JScript as IActiveScriptParse;
  hr := JScriptParse.InitNew;

  hr := CoCreateInstance(CLSID_VBScript, nil, CLSCTX_INPROC_SERVER, IID_IActiveScript, VBScript);
  hr := VBScript.SetScriptSite(ScriptSite);
  VBScriptParse := VBScript as IActiveScriptParse;
  hr := VBScriptParse.InitNew;

  // Run some scripts
  hr := JScriptParse.ParseScriptText('(new Date()).getTime()', nil, nil, nil, 0, 0, SCRIPTTEXT_ISEXPRESSION, @res, ei);
  hr := VBScriptParse.ParseScriptText('Now', nil, nil, nil, 0, 0, SCRIPTTEXT_ISEXPRESSION, @res, ei);
  hr := VBScriptParse.ParseScriptText('MsgBox "Hello World! The current time is: " & Now', nil, nil, nil, 0, 0, 0, @res, ei);;
end;

end.

Just run the TestActiveScriptingOuter method. You should get a MsgBox from VBScript and in the debugger you can see how expressions are evaluated and passed to the Res variant.

What this example does not show is how to pass in COM objects that the script can interact with. This should be possbile via IActiveScript.AddNamedItem and IActiveScriptSite.GetItemInfo.

Also there is no error checking in the code which you should add before using it in production!

Mckean

Answer 4

You don't need any thrid party components for using Windows Script Host. We use it for ten years and have built a huge ERP system around it with more than 1 million of source code lines in VBScript.

You should use Windows Script Control in order to tell to Windows Script Host or just connect directly through known interfaces.

Hummer