Zip file not seekable

Question

I'm trying to do some file manipulation on a zipped file. I'm a little confused on why the file like object that .open is returning a file like that's not seekable. Can any one shed some light on this?

This is the code I'm using. How can I make file_like's seekable?

zipped_archive = ZipFile(filepath, mode='r')
file_like = zipped_archive.open(file_name, mode='r')
file_like.seekable() # returns False

Answer 1

The ZipFile.open method returns a ZipExtFile object which does not implement seeking. The default value for seekable in io.IOBase is False .

I'm not sure why seeking was never implemented but I'd guess seeking by byte in a compressed file might be difficult for some reason.

Answer 2

在Python 3.7版（ 问题 ）中修复

Answer 3

A very helpful and simple work around that helped me is to add seekable to the file I used:

def add_seekable_to_file(f):
    """
    If file f does not has seekable function -
    add seekable function that will always return true
    Args:
        f: the file
    Returns: the file f with seekable function

    """
    if not hasattr(f, "seekable"):
        # AFAICT all the filetypes that STF wraps can seek
        f.seekable = lambda: True

add_seekable_to_file(datazip.fp)