Using Python Requests to Populate Date Fields in Web Forms

When working with web scraping and automation, you may need to fill out date fields in online forms. However, these date pickers can be tricky to handle. Thankfully, the Python Requests library provides some useful tools to populate these date values.

The Problem with Date Pickers

Many web forms use JavaScript-powered date picker widgets rather than a standard text input. These prevent users from manually typing a date, forcing them to click through a calendar interface. For web automation, this presents a challenge as the date can't be entered directly.

# This WON'T work
import requests

data = {
   'date': '2023-03-15' 
}

r = requests.post(url, data=data)

Trying to directly assign a date string will likely result in an invalid value error from the server. So how can we set the date programmatically?

Leveraging Request Headers

The key is to use Requests header values to tell the server we are submitting a valid date from the date picker widget. We need to add headers like:

X-Requested-With: XMLHttpRequest

This header indicates an AJAX request originating from JavaScript, similar to a date picker selection.

Putting it All Together

Here is working Python code to populate a date field using the Requests library:

import requests

data = {
   'date': '2023-03-15'  
}

headers = {
   'X-Requested-With': 'XMLHttpRequest'
}

r = requests.post(url, json=data, headers=headers)

By adding the right headers, the server will process our date string as if it came from user clicks in the JavaScript widget.

The key takeaways are to use the headers to simulate an AJAX request and match the expected date string format. With some tweaking for each site, this approach provides a way to programmatically populate tricky date pickers for test automation.