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 run(self):
        """
        Replays the transaction.
        """

        fn = self._filename
        errors = []

        for pkg_data in self._rpms:
            try:
                self._replay_pkg_action(pkg_data)
            except TransactionError as e:
                errors.append(e)

        for group_data in self._groups:
            try:
                action = group_data["action"]
                group_id = group_data["id"]

                try:
                    pkg_types = libdnf.transaction.stringToCompsPackageType(group_data["package_types"])
                except libdnf.error.Error as e:
                    errors.append(TransactionError(str(e)))
                    continue

                if action == "Install":
                    self._swdb_group_install(group_id, pkg_types, group_data["packages"])
                elif action == "Upgrade":
                    self._swdb_group_upgrade(group_id, pkg_types, group_data["packages"])
                elif action == "Removed":
                    self._swdb_group_remove(group_id, pkg_types, group_data["packages"])
                else:
                    errors.append(TransactionError(
                        _('Unexpected value of group action "{action}" for group "{group}".')
                            .format(action=action, group=group_id)
                    ))
            except KeyError as e:
                errors.append(TransactionError(
                    _('Missing object key "{key}" in a group.').format(key=e.args[0])
                ))
            except TransactionError as e:
                errors.append(e)

        for env_data in self._environments:
            try:
                action = env_data["action"]
                env_id = env_data["id"]

                try:
                    pkg_types = libdnf.transaction.stringToCompsPackageType(env_data["package_types"])
                except libdnf.error.Error as e:
                    errors.append(TransactionError(str(e)))
                    continue

                if action == "Install":
                    self._swdb_environment_install(env_id, pkg_types, env_data["groups"])
                elif action == "Upgrade":
                    self._swdb_environment_upgrade(env_id, pkg_types, env_data["groups"])
                elif action == "Removed":
                    self._swdb_environment_remove(env_id, pkg_types, env_data["groups"])
                else:
                    errors.append(TransactionError(
                        _('Unexpected value of environment action "{action}" for environment "{env}".')
                            .format(action=action, env=env_id)
                    ))
            except KeyError as e:
                errors.append(TransactionError(
                    _('Missing object key "{key}" in an environment.').format(key=e.args[0])
                ))
            except TransactionError as e:
                errors.append(e)

        if errors:
            raise TransactionReplayError(fn, errors)