Runtime introspection of linked SWC using ActionScript 3.0 + Flash/Flex

Question

Wow, my first post on Stack Overflow. Have I "arrived"?

Okay, this is an oddball. I'm trying to determine whether there might be some programmatic way to introspect the classes within a linked SWC at runtime.

To give a little more background (maybe there's a completely different way to go about doing this), I'm considering a general framework for Font Embedding. Currently, to embed fonts (using a linked SWC, not the [embed] metatag), you need to embed the font in your SWC using the Flash IDE, and then you need to hard-code a reference to the library asset's Class in your code (possibly being created by someone else, using a different IDE - FlashDevelop for instance).

Now, if it were possible at runtime to introspect the SWC and iterate through the classes it exposes, one could theoretically instantiate/register these fonts programatically without having to know (at compile time) what those fonts might be.

Hence the question: does anyone know of any way to access the SWC as an entity at runtime and introspect its exposed Classes?

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As an aside, the rationale for this sort of thing is a simple desire for clean separation of design and application logic responsibilities. It's easy for a Designer to embed the font and author and SWC, and also edit a corresponding external CSS file. It's much more dangerous to count on them to update the hard references to the classes in code, or count on the client not changing their mind about the font usage after the job has been compiled and released.

Answer 1

You should look at FLexSpy (fxspy) http://code.google.com/p/fxspy/

There are some others out there that will be helpful, too:

KapInspect: http://lab.kapit.fr/display/kapinspect/Kap+Inspect

DeMonster DeBugger: http://demonsterdebugger.com/

Answer 2

You could load the file in as a binary (or use the bytes property of the stage's LoaderInfo if it's the main file), look through the 'tags' for the ABC data, parse it, and look for the data you need. It is a hassle though.

There are such things as font tags. DefineFont2 (tag type 48) which contains a FontID and a FontName, DefineFontName (tag type 88) which also contains FontID and FontName. Maybe that's the data you need. If it is, then it can be insanely quick to look through even the largest of files.

You can read through the .swf file format specification here: http://www.adobe.com/devnet/swf.html