How do I produce a screenshot of a flash swf on the server?

Question

I'm writing a flash app using the open source tools. I would like to load a data file in to the app and capture a screenshot of the stage on the server. The only part that seems mysterious is running the app on the server. In fact, I don't even care if it's the same app running on the server and in the browser--if I can use the flash stage and drawing routines to produce an image server-side, I'm happy. If I have to delve in to flex, fine. Right now I'm having problems finding any starting point at all.

I gather Adobe has some commercial products that may fit the bill, but I'd like to stick with open source, apache, and linux. I know this is probably possible with haxe/neko, but I'd like to use more mainstream tools if possible. Am I asking too much?

EDIT/CLARIFICATION: Many thanks for the responses so far, but I think I've been a bit muddy in my description. I've already written the actual stage-grabbing stuff using the same PNGEncoder class as was suggested. The problem is in actually running the swf on the server side. I don't want to let the client take the screen shot itself, because this opens up the possibility of the client maliciously submitting a screenshot which does not correspond to what is on the stage, that is, I don't want users uploading porn. If I could run the the actionscript code on the server, then I could generate the screenshot from my data files and be sure that the screenshot matches the data, but I have no idea how to run the actionscript or swf on the server.

Answer 1

Did you try actionscript print commands?

Answer 2

Try and look at this: http://www.phpclasses.org/browse/package/4312.html

Answer 3

Swfs run on a client computer, not on the server. The only way it would run on the server would be if you set up a special environment on your server so that it ran a web browser, opened up the page and ran the swf. But even then it would have no correlation to what an external user was doing.

You'll need to run it client side. As far as your security concerns, the best way to get rid of those is to have the php writing the actual image only accept an encrypted form of the image file, which the flash can encrypt. That way they can't simply use the PHP file to upload whatever image they want unless they happened to encrypt it the exact same that your swf did. Next encrypt the swf itself (I recommend SWF Shield) so that a potential hacker cannot read the code to know how to encrypt the image.

Answer 4

We just completed a similar project where we rendered JPGs from SWFs that loaded dynamic data, we used IECapt

Answer 5

I know this question is long dead, but I had a similar problem and ended up writing a script using applescript + ui scripting to grab the inside area of the preview window of the standalone flash player in OS X. You can grab it off github here.