Adding a string to a tarfile in Python

Wrap the string in an io.BytesIO first, then create a TarInfo object and pass them both to addfile() to add the string to your tarfile.

I was writing some Python to write data to a tarfile, and I couldn’t find an obvious way to write a string to a tarfile. If it’s a zip file, you can use ZipFile.writestr(), but there isn’t an equivalent method on TarFile.

Fortunately, it wasn’t difficult to work out – I can turn my string into a file-like object by wrapping it in io.BytesIO, then passing that to TarFile.addfile().

Here’s a simple example:

import io
import tarfile


message = "hello world!"
filename = "greeting.txt"


with tarfile.TarFile("example.tar.gz", "w") as tf:
    msg_as_bytes = message.encode("utf8")
    buffer = io.BytesIO(msg_as_bytes)

    info = tarfile.TarInfo(name=filename)
    info.size = len(msg_as_bytes)

    tf.addfile(tarinfo=info, fileobj=buffer)