Passing Parameters in URLs with Python's urllib

When constructing URL requests in Python, you'll often need to append parameters to the URL to pass additional data to the server. The urllib module provides easy ways to handle this.

For example, say we need to call a URL like:

https://api.example.com/data?category=science&format=json

This passes two parameters, category and format, to the server. Here's how to construct that in Python:

import urllib.parse
import urllib.request

base_url = 'https://api.example.com/data'
params = {'category': 'science', 'format': 'json'}

url = '{}?{}'.format(base_url, urllib.parse.urlencode(params))

data = urllib.request.urlopen(url).read()

The key points:

We construct a dictionary params containing the parameters we want to pass

We use urllib.parse.urlencode() to encode the dictionary in a URL-safe format

We append the encoded parameters to the base URL to construct the full URL

We can then use urllib.request.urlopen() to send the request

Some tips:

Always URL-encode parameter values in case they contain special characters

Use a dictionary to track multiple parameters, then encode the whole thing at once

You can also pass the params dictionary directly to urlopen() and it will encode it

For GET requests, params go in the URL; for POSTs, they would go in the request body

Overall, urllib makes it straightforward to pass parameters around. The parse module handles all the encoding details for you. And you can use the standard dictionary methods to easily construct, combine, and manage multiple parameters to pass along.

Passing Parameters in URLs with Python's urllib

Browse by tags:

Browse by language:

The easiest way to do Web Scraping

Passing Parameters in URLs with Python's urllib

The easiest way to do Web Scraping

Don't leave just yet!