PDFNotImplementedError: Unsupported filter: [/'FlateDecode']

[Pique7]

I think the same error/bug/problem like this one: euske/pdfminer#174 .

Solved it by changing pdftypes.py in this way (for pdfminer.six v20240706):

    def decode(self) -> None:
        assert self.data is None and self.rawdata is not None, str(
            (self.data, self.rawdata)
        )
        data = self.rawdata
        if self.decipher:
            # Handle encryption
            assert self.objid is not None
            assert self.genno is not None
            data = self.decipher(self.objid, self.genno, data, self.attrs)
        filters = self.get_filters()
        if not filters:
            self.data = data
            self.rawdata = None
            return
        for (f, params) in filters:

# ----difference with original `decode` method starts here--------
            if isinstance(f, list):
                try:
                    f = resolve1(f[0])
                except AttributeError:
                    f = f
# ----and ends here-----------------------------------------------

            if f in LITERALS_FLATE_DECODE:
                # will get errors if the document is encrypted.
                try:
                    data = zlib.decompress(data)
           ...

I haven't done any extensive tests yet, so this might not work in all cases ...

[dhdaines]

The problem is actually that the filter is an indirect object reference which isn't being resolved by pdfminer.six before checking if it is not a list (the decoding parameters aren't being resolved either). Solution is not as above but rather:

     def get_filters(self) -> List[Tuple[Any, Any]]:
-        filters = self.get_any(("F", "Filter"))
-        params = self.get_any(("DP", "DecodeParms", "FDecodeParms"), {})
+        filters = resolve1(self.get_any(("F", "Filter"), []))
+        params = resolve1(self.get_any(("DP", "DecodeParms", "FDecodeParms"), {}))