Mini Shell

import functools
import hashlib
import time
from pathlib import Path
from flask import current_app as app, redirect, url_for
from flask import g, session, abort, request
from bakmgr.api.bakauth import get_reg_details

MAX_SESSION_LENGTH = 2592000  # 30 days
HASH_PATH = Path("/etc/bakmgr/.dash_passwd")


def get_reg() -> dict:
    if 'bak_reg' not in g:
        g.bak_reg = get_reg_details()
    return g.bak_reg


def iter_dir(dir_path: Path):
    try:
        for path in dir_path.iterdir():
            yield path
    except FileNotFoundError:
        return


def login(func):
    @functools.wraps(func)
    def _login(*args, **kwargs):
        if login_is_valid():
            return func(*args, **kwargs)
        return redirect(url_for('login_page', next=request.url))

    return _login


def login_is_valid():
    if not app.config['SECRET_KEY']:
        abort(500)
    try:
        login_time = int(session['login_time'])
    except (KeyError, ValueError):
        return False
    else:
        return time.time() - login_time < MAX_SESSION_LENGTH


def hash_pw(password: str) -> str:
    pw_bytes = bytes(password, encoding='utf-8', errors='backslashreplace')
    # the purpose of the version number '1' here is to determine which hashing
    # algo was used, in case we want to change it later.
    return f"1:{hashlib.sha512(pw_bytes).hexdigest()}"


def read_pw_hash():
    try:
        line = HASH_PATH.read_text('ascii')
        ver, hashed = line.split(':', maxsplit=1)
    except (ValueError, OSError):
        return None
    if ver == '1' and len(hashed) == 128:
        return line
    return None