Add a download progress bar

PFERD/utils.py

@@ -9,6 +9,8 @@ from typing import Optional, Tuple, Union
 import bs4
 import requests
 
+from .progress import ProgressSettings, progress_for, size_from_headers
+
 PathLike = Union[PurePath, str, Tuple[str, ...]]
 
 
@@ -41,17 +43,33 @@ def soupify(response: requests.Response) -> bs4.BeautifulSoup:
     return bs4.BeautifulSoup(response.text, "html.parser")
 
 
-def stream_to_path(response: requests.Response, target: Path, chunk_size: int = 1024 ** 2) -> None:
+def stream_to_path(
+        response: requests.Response,
+        target: Path,
+        progress_name: Optional[str] = None,
+        chunk_size: int = 1024 ** 2
+) -> None:
     """
     Download a requests response content to a file by streaming it. This
     function avoids excessive memory usage when downloading large files. The
     chunk_size is in bytes.
+
+    If progress_name is None, no progress bar will be shown. Otherwise a progress
+    bar will appear, if the download is bigger than an internal threshold.
     """
 
     with response:
+        length = size_from_headers(response)
+        if progress_name and length and int(length) > 1024 * 1024 * 10:  # 10 MiB
+            settings: Optional[ProgressSettings] = ProgressSettings(progress_name, length)
+        else:
+            settings = None
+
         with open(target, 'wb') as file_descriptor:
-            for chunk in response.iter_content(chunk_size=chunk_size):
-                file_descriptor.write(chunk)
+            with progress_for(settings) as progress:
+                for chunk in response.iter_content(chunk_size=chunk_size):
+                    file_descriptor.write(chunk)
+                    progress.advance(len(chunk))
 
 
 def prompt_yes_no(question: str, default: Optional[bool] = None) -> bool: