SapConnection.vbs

Option Explicit

'--------------------------------------------------------------------------------
' ScriptName    : SapConnection.vbs
' Creator       : Sungman Han
' Creation Date : 2019-05-28
' Description   : Attaches to a running SAP GUI, opens a connection and logs on.
'
' Usage         : set SAP_PASSWORD=<password>
'                 cscript //nologo SapConnection.vbs <connectionString> <language> <user>
'
' Why the password comes from the environment:
'                 command line arguments are visible to every process on the box
'                 (Task Manager details column, WMI Win32_Process, Sysmon event 1),
'                 so a password must never be passed as an argument.
'
' Exit codes    : 0 ok | 1 bad arguments | 2 SAP GUI unavailable
'
' Requires      : SAP GUI for Windows with scripting enabled on both the client
'                 (Options > Accessibility & Scripting) and the server
'                 (profile parameter sapgui/user_scripting = TRUE).
'--------------------------------------------------------------------------------

Const MAX_ATTEMPTS     = 60
Const POLL_INTERVAL_MS = 500

Dim vConnectionString, vLanguage, vUserName, vPassword
Dim vApplication, vConnection, vSession

If WScript.Arguments.Count < 3 Then
  WScript.StdErr.WriteLine "Usage: cscript //nologo SapConnection.vbs <connectionString> <language> <user>"
  WScript.StdErr.WriteLine "       the password is read from the SAP_PASSWORD environment variable"
  WScript.Quit 1
End If

vConnectionString = WScript.Arguments.Item(0)
vLanguage         = WScript.Arguments.Item(1)
vUserName         = WScript.Arguments.Item(2)
vPassword         = CreateObject("WScript.Shell").Environment("Process").Item("SAP_PASSWORD")

If vPassword = "" Then
  WScript.StdErr.WriteLine "SAP_PASSWORD is not set."
  WScript.Quit 1
End If

Set vApplication = WaitForScriptingEngine()
Set vConnection  = WaitForConnection(vApplication, vConnectionString)
Set vSession     = WaitForSession(vConnection)

If IsObject(WScript) Then
  WScript.ConnectObject vSession, "on"
  WScript.ConnectObject vApplication, "on"
End If

'--------------------------------------------------------------------------------
' Logon screen
'--------------------------------------------------------------------------------
vSession.findById("wnd[0]").maximize
vSession.findById("wnd[0]/usr/txtRSYST-LANGU").Text = vLanguage
vSession.findById("wnd[0]/usr/txtRSYST-BNAME").Text = vUserName
vSession.findById("wnd[0]/usr/pwdRSYST-BCODE").Text = vPassword
vSession.findById("wnd[0]").sendVKey 0

vPassword = ""
WScript.Quit 0

'--------------------------------------------------------------------------------
' Function List
'--------------------------------------------------------------------------------

' The three waits below share one shape: the SAP GUI object model is populated
' asynchronously, so every step is polled instead of assumed present. Each gives
' up after MAX_ATTEMPTS rather than spinning forever.

Function WaitForScriptingEngine()
  Dim vGuiAuto, vEngine, vAttempt

  Set vEngine = Nothing
  For vAttempt = 1 To MAX_ATTEMPTS
    On Error Resume Next
    Set vGuiAuto = GetObject("SAPGUI")
    If Err.Number = 0 Then Set vEngine = vGuiAuto.GetScriptingEngine
    Err.Clear
    On Error GoTo 0

    If Not vEngine Is Nothing Then
      Set WaitForScriptingEngine = vEngine
      Exit Function
    End If
    WScript.Sleep POLL_INTERVAL_MS
  Next

  Fail 2, "SAP GUI scripting engine not available. Is SAP Logon running and scripting enabled?"
End Function

Function WaitForConnection(vApp, vConnStr)
  Dim vConn, vAttempt

  Set vConn = Nothing
  For vAttempt = 1 To MAX_ATTEMPTS
    On Error Resume Next
    Set vConn = vApp.OpenConnectionByConnectionString(vConnStr, True)
    Err.Clear
    On Error GoTo 0

    If Not vConn Is Nothing Then
      Set WaitForConnection = vConn
      Exit Function
    End If
    WScript.Sleep POLL_INTERVAL_MS
  Next

  Fail 2, "Could not open a connection for: " & vConnStr
End Function

Function WaitForSession(vConn)
  Dim vSess, vAttempt

  Set vSess = Nothing
  For vAttempt = 1 To MAX_ATTEMPTS
    On Error Resume Next
    Set vSess = vConn.Children(0)
    Err.Clear
    On Error GoTo 0

    If Not vSess Is Nothing Then
      Set WaitForSession = vSess
      Exit Function
    End If
    WScript.Sleep POLL_INTERVAL_MS
  Next

  Fail 2, "The connection never produced a session."
End Function

Sub Fail(vCode, vMessage)
  WScript.StdErr.WriteLine vMessage
  WScript.Quit vCode
End Sub