urllib.urlretrieve in Python 3

Introduction

In Python, urllib.urlretrieve is a function that allows you to retrieve files from the web using a URL. However, the urllib module has been divided into several modules in Python 3, and urlretrieve has been moved to the urllib.request module. This module provides a higher-level interface for working with URLs.

This guide will explain how to use urllib.urlretrieve in Python 3 to download files from the web. It will also cover some examples and important considerations.

Syntax

The syntax for urllib.request.urlretrieve in Python 3 is as follows:

urllib.request.urlretrieve(url, filename=None, reporthook=None, data=None)

• url: The URL of the file you want to download.
• filename: Optional. The local filename under which the file is saved. If not specified, a temporary file will be created.
• reporthook: Optional. A function used to report the progress of the download.
• data: Optional. Any data that you want to send with the request.

Example

Here is an example that demonstrates how to use urllib.request.urlretrieve:

import urllib.request

url = 'https://example.com/file.txt'
filename = 'myfile.txt'

urllib.request.urlretrieve(url, filename)

print('File downloaded successfully.')

In this example, the file located at the specified URL https://example.com/file.txt will be downloaded and saved as myfile.txt in the current directory.

Considerations

When using urllib.request.urlretrieve, there are a few important considerations to keep in mind:

1. By default, the function retrieves the entire contents of the file at the URL. It is suitable for small files, but for larger files, it may consume a lot of memory.
2. If the filename parameter is not provided, a temporary file will be created and its path will be returned instead.
3. The reporthook parameter can be used to monitor the progress of the download. It takes a callable object as an argument that will be called with a data block and the total size of the file being downloaded.
4. If the specified URL is unable to be accessed or the file does not exist, urlretrieve will raise an exception.
5. urlretrieve is a blocking function, meaning the program execution will be paused until the download is complete. If you need to download multiple files simultaneously, consider using asynchronous techniques or multiprocessing.

Remember to handle errors appropriately, such as catching exceptions and providing appropriate error messages to the user.

Conclusion

urllib.request.urlretrieve is a useful function in Python 3 for downloading files from the web. It is a part of the urllib.request module and provides a simple way to retrieve files using a URL. Make sure to consider the mentioned considerations while using this function in your programs.