def download_file(url, dest=None, chunk_size=1024, replace="ask",
                  label="Downloading {dest_basename} ({size:.2f}MB)",
                  expected_extension=None):
    """Download a file from a given URL and display progress.

    :param dest: If the destination exists and is a directory, the filename
        will be guessed from the Content-Disposition header. If the destination
        is an existing file, the user will either be prompted to overwrite, or
        the file will be replaced (depending on the value of **replace**). If
        the destination does not exist, it will be used as the filename.
    :param int chunk_size: bytes read in at a time.
    :param replace: If `False`, an existing destination file will not be
        overwritten.
    :param label: a string which is formatted and displayed as the progress bar
        label. Variables provided include *dest_basename*, *dest*, and *size*.
    :param expected_extension: if set, the filename will be sanitized to ensure
        it has the given extension. The extension should not start with a dot
        (`.`).
    """
    dest = Path(dest or url.split("/")[-1])
    response = get(url, stream=True)
    if (dest.exists()
            and dest.is_dir()
            and "Content-Disposition" in response.headers):
        content_disposition = rfc6266.parse_requests_response(response)
        if expected_extension is not None:
            filename = content_disposition.filename_sanitized(
                expected_extension)
        filename = secure_filename(filename)
        dest = dest / filename
    if dest.exists() and not dest.is_dir():
        if (replace is False
                or replace == "ask"
                and not click.confirm("Replace {}?".format(dest))):
            return str(dest)
    size = int(response.headers.get("content-length", 0))
    label = label.format(dest=dest, dest_basename=dest.name,
                         size=size/1024.0/1024)
    with click.open_file(str(dest), "wb") as f:
        content_iter = response.iter_content(chunk_size=chunk_size)
        with click.progressbar(content_iter, length=size/1024,
                               label=label) as bar:
            for chunk in bar:
                if chunk:
                    f.write(chunk)
                    f.flush()
    return str(dest)
def overview():
    # user and group stats
    banned_users = User.query.filter(
        Group.banned == True,
        Group.id == User.primary_group_id
    ).count()
    if not current_app.config["REDIS_ENABLED"]:
        online_users = User.query.filter(User.lastseen >= time_diff()).count()
    else:
        online_users = len(get_online_users())

    stats = {
        # user stats
        "all_users": User.query.count(),
        "banned_users": banned_users,
        "online_users": online_users,
        "all_groups": Group.query.count(),
        # forum stats
        "report_count": Report.query.count(),
        "topic_count": Topic.query.count(),
        "post_count": Post.query.count(),
        # misc stats
        "plugins": get_all_plugins(),
        "python_version": "%s.%s" % (sys.version_info[0], sys.version_info[1]),
        "flask_version": flask_version,
        "flaskbb_version": flaskbb_version
    }

    return render_template("management/overview.html", **stats)