如何在 Python 3 中合并两个 tar gz BinaryIO

Question

我有两个二进制 I/O 流（都继承自 BufferedIOBase），它们代表两个 tar 使用 gzip 算法压缩的档案。

有没有什么有效的方法可以创建第三个，它是另外两个的组合？

我尝试通过 fileobj 参数将两个流都转换为 tarfile.Tarfile 并将每个成员添加到第三个：

def merge_environment(a: Optional[BinaryIO], b: Optional[BinaryIO]) -> Optional[BinaryIO]:
    """Merge <a> and <b>, returning a new tarfile.TarFile object.

    If two files in <a> and <b> have the same name, the one in <a> prevails."""
    destio = io.BytesIO()

    with tarfile.open(fileobj=a, mode="r:gz") as t1, \
            tarfile.open(fileobj=b, mode="r:gz") as t2, \
            tarfile.open(fileobj=destio, mode="w:gz") as dest:

        t1_members = [m for m in t1.getmembers() if m.name != ""]
        t1_names = [m.name for m in t1.members]
        t2_members = [m for m in t1.getmembers() if m.name != "" and m.name not in t1_names]

        for member in t1_members:
            dest.addfile(member, t1.extractfile(member))
        for member in t2_members:
            dest.addfile(member, t2.extractfile(member))

    destio.seek(0, 0)
    return destio

但是，如果任何 tar.gz 包含目录，这将不起作用，因为 tarfile.extractfile() 不适用于目录。

有什么解决办法吗？

Answer 1

解决方案很简单，tarfile.addfile 的 fileobj 参数不是强制性的，tarinfo 就足够了：

destio = io.bytesIO()
with tarfile.open(fileobj=a, mode="r:gz") as t1, \
        tarfile.open(fileobj=b, mode="r:gz") as t2, \
        tarfile.open(fileobj=destio, mode="w:gz") as dest:

    t1_members = [m for m in t1.getmembers()]
    t1_names = t1.getnames()
    t2_members = [m for m in t2.getmembers() if m.name not in t1_names]

    for member in t1_members:
        if member.isdir():
            dest.addfile(member)
        else:
            dest.addfile(member, t1.extractfile(member))

    for member in t2_members:
        if member.isdir():
            dest.addfile(member)
        else:
            dest.addfile(member, t2.extractfile(member))

如何在 Python 3 中合并两个 tar gz BinaryIO

How to merge two tar gz BinaryIO in Python 3

python

tarfile

python-3.x