Comprehensive Python Guide to Download Files from the Web, S3, and Other Sources

In this tutorial you will learn how to use various Python modules to download files from the web, Amazon S3, and other resources.

1. Using requests : Fetch a URL with requests.get(url) and write the response to a file named myfile .

2. Using wget : Install the wget module via pip install wget and download a file with wget.download(url, path) .

3. Downloading redirected files : Use requests.get(url, allow_redirects=True) to follow redirects and save the final content.

4. Chunked download of large files : Set stream=True in requests.get , iterate over response.iter_content(chunk_size=1024) , and write each chunk to a file, optionally displaying a progress bar.

5. Parallel/batch download : Import os , time , and ThreadPool to run multiple download threads simultaneously, measuring total time.

6. Progress bar with clint : Install clint via pip install clint and wrap the write loop with clint.textui.progress.bar to show download progress.

7. Using urllib : Download a webpage with urllib.request.urlretrieve(url, filename) , no extra installation needed.

8. Download via proxy : Create a urllib.request.ProxyHandler and an opener with urllib.request.build_opener(proxy) to fetch resources through a proxy server.

9. Using urllib3 : Install urllib3 via pip install urllib3 , create a PoolManager , and retrieve content similarly to urllib .

10. Downloading from Amazon S3 with boto3 : Install boto3 and awscli , configure credentials, then use boto3.resource('s3').Bucket(bucket_name).download_file(key, local_path) to fetch objects.

11. Asynchronous download with asyncio : Define async coroutines using async def , employ await for I/O operations, and run them with an event loop via asyncio.get_event_loop().run_until_complete() to download multiple files concurrently.

The guide concludes with encouragement to apply these techniques for various download needs.