yaswfp 0.9.3

Yet Another SWF Parser.

Yet Another SWF Parser.

You can pronounce whatever you like :)

How to use it

You can use swfparser.py as command line program or as a module.

If you execute directly the usage is:

swfparser.py [-h] [-t] [-e] filepath

positional arguments:
  filepath         the SWF file to parse

optional arguments:
  -h, --help       show this help message and exit
  -t, --show-tags  show the first level tags of the file
  -e, --extended   show all objects with full detail and nested

If you want to use it as a module, you can use the SWFParser class directly or the handy parsefile function:

>>> swf = swfparser.parsefile(<yourSWFfile>)
>>> swf.header
Header(name=Header, FileLength=4228, ...)
>>> len(swf.tags)
365
>>> swf.tags[0]
UnknownObject(name=SetBackgroundColor, raw_payload=b'\xff\xff\xff')
>>> swf.tags[3]
>>> obj = swf.tags[3]
>>> obj
PlaceObject2(name=PlaceObject2, CharacterId=1, ...)
>>> obj.CharacterId
1
>>> obj.Matrix.ScaleX
65536

This follows the SWF File Format Specification Version 19, but it is not (yet) 100% covered, so you may find some unknown objects.

How to deal with still-unknown-objects

Not all the spec is covered (this is a work in progress!).

When the parser finds a structure that still can’t process (because more programming is needed), will just return an UnknownObject object with the unparsed bytes, or will raise an exception if you set the unknown_alert flag:

SWFParser.unknown_alert = True

Add new structures to the parser is very simple. I’ll be very glad to do it if you offer a real stream of bytes as an example or even a sample SWF file with the still missing object inside.

Checking coverage

There is an easy way of checking how many of the objects (tags, actions, structures, etc) are properly covered by the parser: just use the coverage parameter:

$ python3 yaswfp/swfparser.py -c yaswfp/tests/samples/1252533834.swf
Header(Signature='CWS', ...)
Tags count: 55
Coverage is 97.3% of 74 total items
Most common parsed objects:
   22 PlaceObject2
   21 ShowFrame
   10 LineStyleArray
Most common Unknown objects
    2 DefineMorphShape2

Development

To run the tests:

./test

You’ll need python3-flake8 and python3-nose. Of course, this is Python 3.

To complete some methods or be able to parse new structures, we should add examples that show that new stuff, see current “sanity” tests. Yes, unit tests are desirable, feel free to add those too.

The project is hosted in GitHub:

https://github.com/facundobatista/yaswfp

Contact

Any doubt, any question, any suggestion, or whatever, feel free to open an issue in GitHub or find me in IRC, I’m facundobatista in Freenode.

Thanks!