Guess file type from python on macOS, no dependencies

file.py

import contextlib
import subprocess

def file_proc():
    args = [
        '/usr/bin/file',
        '--brief',
        '-E',
        '--no-dereference',
        '--no-buffer',
        '--preserve-date',
        '-00',
        '--mime-type',
        '--files-from', '-'
    ]

    with contextlib.ExitStack() as stack:
        proc = subprocess.Popen(args, bufsize=0, stdin=subprocess.PIPE, stdout=subprocess.PIPE, preexec_fn=None, text=True)
        stack.callback(proc.kill)

        while True:
            file_path = yield
            proc.stdin.write(file_path + '\n')
            proc.stdin.flush()

            file_type = ''
            while (c := proc.stdout.read(1)) != '\0':
                file_type += c

            yield file_type.splitlines()[0]


@contextlib.contextmanager
def file_typer():
    proc = file_proc()

    def getter(path):
        proc.send(None)
        posix_type = proc.send(path.as_posix())
        return posix_type

    with contextlib.closing(proc):
        yield getter
        

with file_typer() as typer:
  typer('/usr/bin/python')

#libmagic #python-magic #file