Module refinery.units.formats.archive.xtchm

Expand source code Browse git 
from __future__ import annotations

from refinery.lib.chm import CHM, ChmHeader
from refinery.units.formats import PathExtractorUnit, UnpackResult


class xtchm(PathExtractorUnit, docs='{0}{p}{PathExtractorUnit}'):
    """
    Extract files from CHM (Windows Help) files. Compiled HTML Help archives contain HTML, images,
    and scripts used in Microsoft Help.
    """
    def unpack(self, data):
        chm = CHM.Parse(memoryview(data))

        self.log_info(F'language: {chm.header.language_name}')
        self.log_info(F'codepage: {chm.header.codepage}')

        for path, record in chm.filesystem.items():
            def extract(chm=chm, record=record):
                return chm.read(record)
            if record.length <= 0:
                continue
            if path.startswith('::DataSpace'):
                continue
            yield UnpackResult(path, extract)

    @classmethod
    def handles(cls, data):
        return data[:4] == ChmHeader.Magic

Classes

class xtchm (*paths, list=False, join_path=False, drop_path=False, fuzzy=0, exact=False, regex=False, path=b'path')

Extract files from CHM (Windows Help) files. Compiled HTML Help archives contain HTML, images, and scripts used in Microsoft Help.

This unit extracts items with an associated virtual path from a container. Each extracted item is emitted as a separate chunk and has attached to it a meta variable that contains its path within the container format. The positional arguments to the command are patterns that can be used to filter the extracted items by their path. To view only the paths of all chunks, use the listing switch:

emit something | xtchm --list

Otherwise, extracted items are written to the standard output port and usually require a frame to properly process. In order to dump all extracted data to disk, the following pipeline can be used:

emit something | xtchm [| dump extracted/{path} ]

The value {path} is a placeholder which is substituted by the virtual path of the extracted item. When using xtchm to unpack a file on disk, the following pattern can be useful:

ef pack.bin [| xtchm -j | d2p ]

The unit ef is also a path extractor. By specifying -j (or --join), the paths of extracted items are combined. Here, d2p is a shortcut for dump {path}. It deconflicts the joined paths with the local file system: If pack.bin contains items one.txt and two.txt, the following local file tree would be the result:

pack.bin
pack/one.txt
pack/two.txt

Finally, the -d (or --drop) switch can be used to not create (or alter) the path metadata at all, which is useful in cases where path metadata from a previous unit should be preserved.

Expand source code Browse git 
class xtchm(PathExtractorUnit, docs='{0}{p}{PathExtractorUnit}'):
    """
    Extract files from CHM (Windows Help) files. Compiled HTML Help archives contain HTML, images,
    and scripts used in Microsoft Help.
    """
    def unpack(self, data):
        chm = CHM.Parse(memoryview(data))

        self.log_info(F'language: {chm.header.language_name}')
        self.log_info(F'codepage: {chm.header.codepage}')

        for path, record in chm.filesystem.items():
            def extract(chm=chm, record=record):
                return chm.read(record)
            if record.length <= 0:
                continue
            if path.startswith('::DataSpace'):
                continue
            yield UnpackResult(path, extract)

    @classmethod
    def handles(cls, data):
        return data[:4] == ChmHeader.Magic

Ancestors

Subclasses

Class variables

var reverse

The type of the None singleton.

Methods

def unpack(self, data)
Expand source code Browse git 
def unpack(self, data):
    chm = CHM.Parse(memoryview(data))

    self.log_info(F'language: {chm.header.language_name}')
    self.log_info(F'codepage: {chm.header.codepage}')

    for path, record in chm.filesystem.items():
        def extract(chm=chm, record=record):
            return chm.read(record)
        if record.length <= 0:
            continue
        if path.startswith('::DataSpace'):
            continue
        yield UnpackResult(path, extract)

Inherited members