Python CFFI convert structure to dictionary

Question

There is a way to initialize structure with dictionary:

fooData= {'y': 1, 'x': 2}
fooStruct = ffi.new("foo_t*", fooData)
fooBuffer = ffi.buffer(fooStruct)

Is there some ready function to do the conversion?

fooStruct = ffi.new("foo_t*")
(ffi.buffer(fooStruct))[:] = fooBuffer
fooData= convert_to_python( fooStruct[0] )    

Do I have to use ffi.typeof("foo_t").fields by myself?

I come up with this code so far:

def __convert_struct_field( s, fields ):
    for field,fieldtype in fields:
        if fieldtype.type.kind == 'primitive':
            yield (field,getattr( s, field ))
        else:
            yield (field, convert_to_python( getattr( s, field ) ))

def convert_to_python(s):
    type=ffi.typeof(s)
    if type.kind == 'struct':
        return dict(__convert_struct_field( s, type.fields ) )
    elif type.kind == 'array':
        if type.item.kind == 'primitive':
            return [ s[i] for i in range(type.length) ]
        else:
            return [ convert_to_python(s[i]) for i in range(type.length) ]
    elif type.kind == 'primitive':
        return int(s)

Is there a faster way?

Answer 1

Arpegius' solution works fine for me, and is quite elegant. I implemented a solution based on Selso's suggestion to use inspect. dir() can substitute inspect.

from inspect import getmembers
from cffi import FFI
ffi = FFI()
from pprint import pprint

def cdata_dict(cd):
    if isinstance(cd, ffi.CData):
        try:
            return ffi.string(cd)
        except TypeError:
            try:
                return [cdata_dict(x) for x in cd]
            except TypeError:
                return {k: cdata_dict(v) for k, v in getmembers(cd)}
    else:
        return cd

foo = ffi.new("""
struct Foo {
    char name[6];
    struct {
        int a, b[3];
    } item;
} *""",{
    'name': b"Foo",
    'item': {'a': 3, 'b': [1, 2, 3]}
})
pprint(cdata_dict(foo))

Output:

{'item': {'a': 3, 'b': [1, 2, 3]}, 'name': b'Foo'}