A utility for handling user credentials to databases

Creds.R

#----AskCreds - so RStudio can access ODBC-------------------

AskCreds <- function(Title="User credentials for a database", startuid="", returnValOnCancel = "ID_CANCEL") {
  # Peter Ellis, 12 August 2013
  # A wrapper function to provide a GUI to ask a user for user id and password so they
  # can be given to a database in a future call of connectODBC()
  # Based on http://www.sciviews.org/_rgui/tcltk/ModalDialog.html
  require(tcltk)
  dlg <- tktoplevel()
  tkwm.deiconify(dlg)
  tkgrab.set(dlg)
  tkfocus(dlg)
  tkwm.title(dlg, Title)
  uidEntryVarTcl <- tclVar(startuid)
  uidEntryWidget <- tkentry(dlg, width = 50, textvariable = uidEntryVarTcl)
  pwdEntryVarTcl <- tclVar("")
  pwdEntryWidget <- tkentry(dlg, width = 50, textvariable = pwdEntryVarTcl, show="X")
  tkgrid(tklabel(dlg, text = "       "))
  tkgrid(tklabel(dlg, text = "User ID"), uidEntryWidget)
  tkgrid(tklabel(dlg, text = "Password"), pwdEntryWidget)
  ReturnVal <- returnValOnCancel
  
  onOK <- function() {
    ReturnVal <<- list(uid=tclvalue(uidEntryVarTcl), pwd=tclvalue(pwdEntryVarTcl))
    tkgrab.release(dlg)
    tkdestroy(dlg)
  }
  onCancel <- function() {
    ReturnVal <<- returnValOnCancel
    tkgrab.release(dlg)
    tkdestroy(dlg)
  }
  OK.but <- tkbutton(dlg, text = "   OK   ", command = onOK)
  Cancel.but <- tkbutton(dlg, text = " Cancel ", command = onCancel)
  tkgrid(OK.but, Cancel.but)
  tkgrid(tklabel(dlg, text = "    "))
  
  tkfocus(dlg)
  
  tkbind(pwdEntryWidget, "<Return>", onOK)
  tkwait.window(dlg)
  
  return(ReturnVal)
}