send a webhook message everytime print starts klipper

3 min read 26-02-2025

send a webhook message everytime print starts klipper

Klipper is a fantastic 3D printing firmware, known for its speed and responsiveness. But wouldn't it be even better if you received instant notifications every time a print begins? This article details how to set up a webhook to send you a message whenever a print starts in your Klipper-powered 3D printer. This allows for remote monitoring and peace of mind, knowing your print has successfully launched.

Why Use Webhooks for Print Start Notifications?

Traditional methods of monitoring prints, like constantly checking the printer's status, are inefficient. Webhooks offer a proactive solution. A webhook is a simple HTTP callback. Whenever a specific event occurs (in our case, a print starting), Klipper sends a message to a pre-defined URL. This URL can be hosted on services like IFTTT, Discord, or custom scripts.

This eliminates the need for constant polling, saving resources and providing near-instant notifications. You'll receive updates directly to your preferred platform – no more refreshing screens!

Setting up the Klipper Configuration

First, you need to modify your Klipper configuration file (printer.cfg). This involves adding a [gcode_macro] section to define a macro that sends the webhook message. You'll need to replace placeholders with your actual webhook URL.

Here’s an example:

[gcode_macro PRINT_START_NOTIFICATION]
gcode:
  {% set webhook_url = "YOUR_WEBHOOK_URL" %}
  ; Replace YOUR_WEBHOOK_URL with your actual webhook URL
  ; Ensure your URL is properly URL-encoded if necessary.
  SET_GCODE_VARIABLE MACRO=send_webhook_message VARIABLE=url VALUE={webhook_url}
  send_webhook_message

Next, we define the send_webhook_message macro. This macro will handle the actual HTTP request to your webhook URL. This is where we leverage the RESPOND command to receive a status code from the webhook receiver. We’ll check for a 200-level success status.

[gcode_macro send_webhook_message]
description: Send a webhook message
gcode:
  ; Get the webhook URL from the variable
  {% set url = params.url %}
  ; Construct the payload (customize as needed)
  {% set payload = { "event": "print_started", "message": "Print started on your Klipper printer!" } %}
  ;  Convert the Python dict to a JSON string
  {% set payload_json = payload | json_encode %}
  ; Send the webhook request
  RUN_EXECUTE_COMMAND python3 -c 'import requests, json; requests.post("{url}", data=json.dumps({payload_json}), headers={"Content-Type": "application/json"})'
  ; Check the response code (optional, but recommended)
  ;  Note that you may need to adapt this section depending on your webhook service
  RESPOND "Webhook sent"

Important Considerations:

Replace "YOUR_WEBHOOK_URL": This is crucial. Substitute this with the actual URL provided by your webhook service (IFTTT, Discord, etc.). Make sure the URL is correctly formatted and URL-encoded if needed. Incorrect URLs will prevent the notification from being sent.
Payload Customization: Adjust the payload section to include any additional data you want to send with your notification (e.g., filename, print time). The structure depends on your webhook receiving service.
Error Handling: Consider adding error handling to your send_webhook_message macro. For example, you could log errors to a file if the webhook request fails.

Setting up Your Webhook Receiver

The next step involves configuring your webhook receiver service. The process varies depending on the service you choose. Here are a few popular options:

IFTTT

IFTTT (If This Then That) is a user-friendly service to create simple automations. You can create an applet that triggers when it receives a POST request to a specific URL. The applet can then send notifications to your preferred platform (e.g., email, SMS, mobile app).

Discord Webhooks

Discord webhooks provide a simple way to send messages to Discord channels. You can create a webhook within your Discord server and obtain its URL. You can then configure your Klipper setup to post messages to that URL.

Custom Solutions

For more control, consider a custom script running on a server. This script could process the webhook data and trigger actions like sending emails or logging data. This solution offers the most flexibility but requires more technical expertise.

Testing Your Setup

After configuring your Klipper settings and webhook receiver, it’s time to test. Start a print and check if the notification arrives. If not, double-check your webhook URL and payload configuration. Inspect your Klipper logs for any errors. The RESPOND command in the send_webhook_message macro will output a response in the Klipper console. This can help in troubleshooting.

Conclusion

Setting up webhook notifications for Klipper print starts enhances the user experience. Receiving instant alerts streamlines your workflow and provides peace of mind, knowing the print has begun successfully. While there’s some initial configuration, the benefits of proactive monitoring outweigh the effort. Remember to carefully replace placeholders and test thoroughly to ensure everything functions correctly!