PyDown: A Beginner’s Guide to Downloading Files with Python
What PyDown is
PyDown is a simple Python library (assumed here as a lightweight downloader) that provides convenient functions for downloading files from URLs, handling common tasks like retries, progress reporting, timeout handling, and basic validation (e.g., file size and checksum checks).
Key features
- Simple API: single-call functions to download a URL to disk.
- Retries & backoff: automatic retry logic for transient network errors.
- Progress reporting: optional console progress bar or callback hook.
- Timeouts: configurable connection and read timeouts.
- Resume support: resumes partial downloads when the server supports range requests.
- Basic validation: optional checksum (MD5/SHA256) and expected size checks.
- Async and sync: both synchronous and asyncio-compatible functions (assumed).
Quick installation
Assuming PyDown is on PyPI:
bash
pip install pydown
Basic usage (synchronous)
python
from pydown import download url = “https://example.com/file.zip” download(url, dest=“file.zip”)
Usage with progress and retries
python
from pydown import download, RetryConfig retry = RetryConfig(retries=3, backoff_factor=0.5) download(“https://example.com/file.zip”, dest=“file.zip”, showprogress=True, retry=retry, timeout=30)
Asynchronous example
python
import asyncio from pydown import async_download async def main(): await async_download(“https://example.com/file.zip”, dest=“file.zip”, show_progress=True) asyncio.run(main())
Advanced options
- Checksum validation: download(…, checksum=“sha256:HEXVALUE”)
- Partial resume: enabled automatically when supported
- Headers and auth: pass custom headers or auth tokens for protected resources
- Rate limiting: limit download speed to avoid saturating bandwidth
Best practices
- Use timeouts and limited retries to avoid hanging processes.
- Validate downloads with checksums when integrity matters.
- Prefer streaming downloads for large files to keep memory use low.
- Respect remote servers: set a sensible User-Agent and optionally rate limit.
Troubleshooting
- If downloads fail with ⁄206 errors, server may not support ranges—disable resume.
- For SSL errors, ensure certificates are up to date or provide cert paths.
- For authentication errors, verify headers/tokens and refresh expired credentials.
If you want, I can generate a short example script that downloads multiple files with checksum verification and concurrent async downloads.
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