Get the File Extension from a URL in Python

Handling URLs in Python often involves extracting valuable information, such as file extensions, from the URL strings. However, this task requires careful consideration to ensure the safety and accuracy of the extracted data. In this article, we will explore four approaches to safely get the file extension from a URL in Python.

Safely Get The File Extension From A Url in Python

Below are some of the ways by which we can safely get the file extension from a URL in Python:

• Using os.path.splitext()
• Handling Query Parameters
• Using Regular Expressions

Safely Get The File Extension Using os.path.splitext() Method

The os.path.splitext method provides a simple way to split the file path and extension. It’s important to note that this approach doesn’t check if the URL points to an actual file; it merely extracts the potential file extension.

Python3

import os

def get_file_extension_os(url):
    _, file_extension = os.path.splitext(url)
    return file_extension

# Example usage:
url = "https://example.com/path/to/file/document.pdf"
extension = get_file_extension_os(url)
print("File extension:", extension)

Output

File extension: .pdf

Safely Get The File Extension by Handling Query Parameters

To ensure robustness, it’s crucial to handle URLs with query parameters properly. This approach removes query parameters before extracting the file extension, preventing interference.

Python3

from urllib.parse import urlparse
import os

def get_file_extension_query_params(url):
    path = urlparse(url).path
    path_without_params, _ = os.path.splitext(path.split('?')[0])
    _, file_extension = os.path.splitext(path_without_params)
    return file_extension

# Example usage:
url = "https://example.com/path/to/file/document.pdf"
extension = get_file_extension_query_params(url)
print("File extension:", extension)

Output:

File extension: pdf

Safely Get The File Extension Using Regular Expressions

For more advanced scenarios, regular expressions can be employed to extract file extensions. This approach allows for greater flexibility and customization.

Python3

import re

def get_file_extension_regex(url):
    match = re.search(r'\.([a-zA-Z0-9]+)$', url)
    if match:
        return match.group(1)
    else:
        return None

# Example usage:
url = "https://example.com/path/to/file/document.pdf"
extension = get_file_extension_regex(url)
print("File extension:", extension)

Output

File extension: pdf