This guide details a clever hack to receive webhook messages whenever a print starts in Klipper, enhancing your monitoring and automation capabilities. This isn't a built-in feature, but with a bit of configuration, you can create a robust solution for integrating Klipper with other services. This is particularly useful for those who want to receive notifications, update dashboards, or trigger other automated actions upon print commencement.
Why Receive a Webhook on Print Start?
Knowing precisely when a 3D print begins offers several advantages:
- Real-time Monitoring: Instantly receive alerts, allowing you to quickly address any issues that may arise during the print's early stages.
- Automated Actions: Trigger other processes, such as updating a status display, sending notifications through various channels (e.g., email, Slack, Discord), or even controlling external hardware.
- Improved Workflow: Seamless integration with other aspects of your smart home or workshop setup.
- Data Collection: Log print start times accurately for detailed analysis and process optimization.
Setting up the Klipper Configuration
This hack relies on Klipper's gcode_macro functionality. We'll create a macro that executes a script upon print start. This script, in turn, will send a webhook request. You'll need to adapt the script to your chosen webhook service (e.g., IFTTT, Zapier, custom server).
First, add the following macro to your printer.cfg file:
[gcode_macro PRINT_START_WEBHOOK]
gcode:
{% set webhook_url = "YOUR_WEBHOOK_URL" %}
; Replace with your actual webhook URL
RUN_SCRIPT_PYTHON /path/to/your/webhook_sender.py {webhook_url}
Replace /path/to/your/webhook_sender.py with the actual path to the Python script you'll create (see below). Critically, replace YOUR_WEBHOOK_URL with your specific webhook URL. This URL is provided by your chosen webhook service and dictates where the notification is sent.
Next, modify your START_PRINT macro (or create one if you don't have it) to include the newly created macro:
[gcode_macro START_PRINT]
gcode:
PRINT_START_WEBHOOK
; ...rest of your START_PRINT macro...
This ensures the webhook is sent every time you initiate a print.
Creating the Python Webhook Sender Script (webhook_sender.py)
This script handles the actual sending of the webhook request. This example uses the requests library. You'll need to install it: pip install requests
import sys
import requests
import json
def send_webhook(webhook_url, data):
try:
response = requests.post(webhook_url, data=json.dumps(data), headers={'Content-Type': 'application/json'})
response.raise_for_status() # Raise an exception for bad status codes
print(f"Webhook sent successfully: {response.status_code}")
except requests.exceptions.RequestException as e:
print(f"Error sending webhook: {e}")
if __name__ == "__main__":
webhook_url = sys.argv[1]
data = {"event": "print_start", "message": "Klipper print started!"} #Customize the message and data sent as needed.
send_webhook(webhook_url, data)
Save this code as webhook_sender.py in the directory specified in your printer.cfg. Remember to make it executable: chmod +x /path/to/your/webhook_sender.py.
Troubleshooting and Common Issues
- Incorrect Webhook URL: Double-check the URL in your
printer.cfgfor typos. - Permission Errors: Ensure the Python script has execute permissions and Klipper has the necessary permissions to run it.
- Network Connectivity: Verify that your Klipper machine has network connectivity.
- Webhook Service Configuration: Make sure your webhook service is correctly configured to receive the requests. Examine any logs or error messages provided by the service.
Extending Functionality
This basic example provides a foundation. You can customize the data dictionary in the Python script to include additional information, such as the filename being printed, estimated print time, or other relevant details. This allows for richer notifications and more sophisticated integrations.
Remember to restart Klipper after making any changes to your printer.cfg file.
This advanced Klipper configuration empowers you to integrate your 3D printing process with your broader smart home or automation setup, significantly improving monitoring and workflow. Experiment with different webhook services and data payloads to tailor the solution to your specific needs.
