[racket] ActiveX support

From: Matthew Flatt (mflatt at cs.utah.edu)
Date: Fri Aug 31 19:58:07 EDT 2012

At Fri, 31 Aug 2012 15:50:46 +0200, heraklea at gmx.de wrote:
> I have an ocx-control and I would like to use it from Racket.
> Is it possible to bind this control in any way to Racket/Scheme?

I think the way to do that is to use IE as an ActiveX container.

Below is an example that starts the "MSCAL.Calendar" control. As you
can see, I didn't figure out how to tell IE that it should trust the
control (so there's an 8-second pause while I click to allow in IE),
but maybe this will be enough to give you some ideas.


#lang racket
(require ffi/com
	 (only-in ffi/unsafe/com
		  ;; This was supposed to be exported from
		  ;; `ffi/com':

;; Write a temporary HTML to load into IE. (There must be a way
;; to do this without temporary files.)
(define f (make-temporary-file "~a.html"))
(with-output-to-file f
  #:exists 'truncate
  (lambda ()
       (head (title "Demo"))
	(h1 "Demo")
	(object ((class "object")
		 (CLASSID ,(format 
			    (let ([s (guid->string 
				      (progid->clsid "MSCAL.Calendar"))])
			      (substring s 1 (sub1 
					      (string-length s)))))))))))))

;; Start IE and navigate to the temporary file
(define ie (com-create-instance "InternetExplorer.Application.1"))
(com-invoke ie "Navigate" (path->string f))

;; Show it:
(com-set-property! ie "Visible" #t)

;; Hack: wait for human to allow blocked content...
(sleep 8)

;; Extract the calendar object:
(define doc (com-get-property ie "Document"))
(define cal (com-get-property 
	     (com-invoke (com-invoke doc "getElementsByTagName" "object")

(com-methods cal)
(com-invoke cal "AboutBox")

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