I'm trying to make a website that allows you to A) Edit FLA files online and B) Export to SWF. It would be easier on a server if everything the user did on the web, it was translated into code. Is it possible to make an Adobe App in just code? And if this is true for AS2 (or should I not even bother)? And is that even legal? Why or why not for all these questions? Thanks for helping! I appreciate your helpfulness.
P.S. What programming language would be best for this kind of website? Client-wise and server-wise. Thanks again!
Yes you can. AFAIK, sites like wonderfl.net use the Flex Module for Apache/IIS (links towards the bottom of the page). This module allows servers to compile .as files into swf files.
A) Edit FLA files online
You would need to understand how the binary format(.fla) stores data and I don't think there are any specifications for the fla format available. You would have to reverse engineer the format. On top of that, you would need to create an interface to mimic the functionalities you need to modify an FLA.
It's probably more realistic to compile .as files into .swf files on the server, and those .as files would be generating by this tool/app you want to build. I can't think of legal issues when compiling .as files to .swf if it's your own code.