Is there a way to acces external .blend file's data with python script? I'm writing an addon to parse a directory (and its sub-dirs) to write an XML file which describe the tree-structure of the assets contained in that directory.
At the moment, my standalone script works pretty well.

The fact is, I need to add some info to the XML, like the dependencies (linked libraries) of each .blend file the script found.

I found a way to do this (outside blender), with the module "pyblenderfile" : http://code.google.com/p/pyblenderfile/

The principle of this module is to open a .blend and get all its data. But it's pretty long and often buggy on large .blend files. Especially since it's included in a for ... loop!

So I wonder if there is a utility function or method into Blender API, to access other .blend files data (without having to wm.open() them) ?
There's no data API for the .blend file format.

However, it sounds like you're trying to make a tool similar to Blender-Aid (code is here). Perhaps that's better place to start.

Note that blendfile.py from Blender-Aid can be used as a standalone blend file reader.