pferd/PFERD/downloaders.py

"""
General downloaders useful in many situations
"""

from pathlib import Path
from typing import Any, Dict, Optional

import requests
import requests.auth

from .organizer import Organizer
from .tmp_dir import TmpDir
from .utils import stream_to_path


# pylint: disable=too-few-public-methods
class HttpDownloader():
    """A HTTP downloader that can handle HTTP basic auth."""

    def __init__(
            self,
            tmp_dir: TmpDir,
            organizer: Organizer,
            username: Optional[str],
            password: Optional[str],
    ):
        """Create a new http downloader."""
        self._organizer = organizer
        self._tmp_dir = tmp_dir
        self._username = username
        self._password = password
        self._session = self._build_session()

    def _build_session(self) -> requests.Session:
        session = requests.Session()
        if self._username and self._password:
            session.auth = requests.auth.HTTPBasicAuth(
                self._username, self._password
            )
        return session

    def download(
            self,
            url: str,
            target_path: Path,
            parameters: Optional[Dict[str, Any]] = None,
    ) -> None:
        """Download a given url to a given path, optionally with some get parameters."""
        parameters = parameters if parameters else {}
        with self._session.get(url, params=parameters, stream=True) as response:
            if response.status_code == 200:
                tmp_file = self._tmp_dir.new_file()
                stream_to_path(response, tmp_file)
                self._organizer.accept_file(tmp_file, target_path)
            else:
                raise Exception(
                    f"Could not download file, got response {response.status_code}"
                )