Add base for simple HTTP downloader

PFERD/http_downloader.py

@@ -0,0 +1,45 @@
+"""Contains a simple HTTP downloader that can handle HTTP basic auth."""
+
+import logging
+from pathlib import Path
+from typing import Any, Dict, Optional
+
+import requests
+import requests.auth
+
+from .new_organizer import Organizer
+from .tmp_dir import TmpDir
+from .utils import stream_to_path
+
+
+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: Dict[str, Any] = {}) -> None:
+        """Download a given url to a given path, optionally with some get parameters."""
+        response = self._session.get(url, params=parameters)
+
+        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}"
+            )