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Overview

The enviar_registro() function is the core component of the WhatsApp Attendance Bot. It automatically sends attendance messages (check-in/check-out) to a WhatsApp group via the Ultramsg API based on the current UTC time.

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Function Signature

def enviar_registro() -> None

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Parameters

The function takes no direct parameters but requires three environment variables:
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INSTANCE_ID
string
required
Your Ultramsg instance ID. Obtained from the Ultramsg dashboard after creating an instance.
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TOKEN
string
required
Your Ultramsg API token for authentication. Found in your Ultramsg instance settings.
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GROUP_ID
string
required
The WhatsApp group ID where messages will be sent. Format: [country_code][phone_number]@g.us (e.g., [email protected])

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Source Code

Location: bot.py:5-24 
def enviar_registro():
    instance_id = os.getenv('INSTANCE_ID')
    token = os.getenv('TOKEN')
    group_id = os.getenv('GROUP_ID')
    
    # Determinar si es entrada o salida según la hora (UTC)
    # Ejemplo: Si estás en México, 15:00 UTC es 9:00 AM
    ahora_hora = datetime.datetime.utcnow().hour
    mensaje = "Aldo Tolentino \n Entrada \n 9:00 AM" if ahora_hora < 18 else "Aldo Tolentino\n Salida\n 3:00 PM"

    url = f"https://api.ultramsg.com/{instance_id}/messages/chat"
    payload = {
        "token": token,
        "to": group_id,
        "body": mensaje
    }
    headers = {'content-type': 'application/x-www-form-urlencoded'}
    
    r = requests.post(url, data=payload, headers=headers)
    print(f"Status: {r.status_code}, Response: {r.text}")

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Function Behavior

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Time-Based Logic

The function determines whether to send a check-in or check-out message based on the current UTC hour:
  • Check-in message: Sent when UTC hour < 18 (before 6:00 PM UTC)
  • Check-out message: Sent when UTC hour >= 18 (6:00 PM UTC or later)
The function uses datetime.datetime.utcnow().hour to get the current UTC hour. For Mexico CST timezone:
  • 15:00 UTC = 9:00 AM CST (check-in)
  • 21:00 UTC = 3:00 PM CST (check-out)

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Message Format

The function sends one of two hardcoded messages: Check-in (before 18:00 UTC): 
Aldo Tolentino 
 Entrada 
 9:00 AM
Check-out (18:00 UTC or later): 
Aldo Tolentino
 Salida
 3:00 PM

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API Integration

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Ultramsg API Endpoint

The function makes a POST request to the Ultramsg chat messages endpoint: 
https://api.ultramsg.com/{INSTANCE_ID}/messages/chat

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Request Payload

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token
string
required
Authentication token from Ultramsg
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to
string
required
WhatsApp group ID in the format [country_code][phone_number]@g.us
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body
string
required
The message text to send to the group

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Request Headers

{'content-type': 'application/x-www-form-urlencoded'}

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Response Handling

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Success Response

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status_code
integer
HTTP status code. 200 indicates success.
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response
object
JSON response from Ultramsg containing message delivery status
The function prints the response to stdout: 
print(f"Status: {r.status_code}, Response: {r.text}")

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Example Output

Status: 200, Response: {"sent":"true","message":"Message sent successfully"}

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Error Handling

The function does not include explicit error handling. If environment variables are missing or the API request fails, the function will raise an exception and the script will exit.
Potential errors:
  • Missing environment variables: os.getenv() returns None, causing the API URL or payload to be invalid
  • Network errors: requests.post() may raise ConnectionError or Timeout
  • API errors: Ultramsg may return 4xx or 5xx status codes

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Usage Example

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Direct Execution

import os
os.environ['INSTANCE_ID'] = 'your_instance_id'
os.environ['TOKEN'] = 'your_token'
os.environ['GROUP_ID'] = '[email protected]'

enviar_registro()

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GitHub Actions

The function is designed to be triggered automatically by GitHub Actions at scheduled times: 
- name: Execute Script
  env:
    INSTANCE_ID: ${{ secrets.INSTANCE_ID }}
    TOKEN: ${{ secrets.TOKEN }}
    GROUP_ID: ${{ secrets.GROUP_ID }}
  run: python bot.py

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Dependencies

  • requests: HTTP library for making API calls (pip install requests)
  • os: Built-in Python module for environment variable access
  • datetime: Built-in Python module for time operations

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Customization

To customize the function behavior, modify these sections in bot.py:

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Change Message Content

Edit line 13: 
mensaje = "Your Name \n Entry \n 9:00 AM" if ahora_hora < 18 else "Your Name\n Exit\n 5:00 PM"

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Change Time Logic

Edit line 13 to change the UTC hour threshold: 
# Change 18 to your desired UTC hour
mensaje = "..." if ahora_hora < 20 else "..."

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Add Error Handling

Wrap the function in a try-except block: 
def enviar_registro():
    try:
        instance_id = os.getenv('INSTANCE_ID')
        if not instance_id:
            raise ValueError("INSTANCE_ID not set")
        # ... rest of the function
    except Exception as e:
        print(f"Error: {e}")
        raise

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