46. Payment preference and user charge

Now, we will add the functionality to charge the user. We will follow the guidance provided in the Mercado Pago API documentation.

Preferences - Advanced features - Mercado Pago Developers

We will start by pasting the following code into our api_mercadopago.py file:

api_mercadopago.py

import mercadopago

public_key = "APP_USR-8e9c2811-1d99-4346-b8a0-9118201f7216"
access_token = "APP_USR-1378561128003766-083016-a08284dad9da4451cc196354af9f6722-1968090813"

#configure your credentials
sdk = mercadopago.SDK(access_token) #? validating access token

# Create items in the preference. preference = personalized charge for clients
preference_data = {
    "items": [
        {
            "title": "Mi producto",
            "quantity": 1,
            "unit_price": 75.56
        },
        {
            "title": "Mi producto2",
            "quantity": 2,
            "unit_price": 96.56
        }
    ], #? links that will be loaded
    "back_urls": {
        "success": "http://localhost:8000/mercadopago/success/",
        "failure": "http://localhost:8000/mercadopago/failure/",
        "pending": "http://localhost:8000/mercadopago/pending/"
    },
}

# Create a preference
preference_response = sdk.preference().create(preference_data) #? creating request with various informations about the payment
link = preference_response["response"]["init_point"]
payment_id = preference_response["response"]["id"] #? obtaining the payment id to treat it

Here's a explanation of the updated code:

• Import Library: import mercadopago

  • Imports the Mercado Pago SDK to handle payment processing.

• API Credentials:

  • public_key = "APP_USR-8e9c2811-1d99-4346-b8a0-9118201f7216"

  • access_token = "APP_USR-1378561128003766-083016-a08284dad9da4451cc196354af9f6722-1968090813"

  • Defines the public key and access token for Mercado Pago authentication.

• Configure SDK: sdk = mercadopago.SDK(access_token)

  • Initializes the Mercado Pago SDK using the access token.

• Preference Data:

  • preference_data: Dictionary containing payment details and URLs.

    • "items": List of items in the order, with each item including:

      • "title": Product name.

      • "quantity": Number of units.

      • "unit_price": Price per unit.

    • "back_urls": Dictionary of URLs to redirect users based on payment status:

      • "success": URL for successful payments.

      • "failure": URL for failed payments.

      • "pending": URL for pending payments.

• Create Preference: preference_response = sdk.preference().create(preference_data)

  • Sends a request to Mercado Pago to create a payment preference with the provided preference_data.

• Extract Response Data:

  • link = preference_response["response"]["init_point"]: Retrieves the URL to redirect the user for payment.

  • payment_id = preference_response["response"]["id"]: Retrieves the unique ID for the created payment preference for further processing.

The dictionary returned in preference_response contains information about the payment, as shown below:

output

{'status': 201, 'response': {'additional_info': '', 'auto_return': '', 'back_urls': {'failure': '', 'pending': '', 'success': ''}, 'binary_mode': False, 'client_id': '1378561128003766', 'collector_id': 1968090813, 'coupon_code': None, 'coupon_labels': None, 'date_created': '2024-08-30T19:17:24.859-04:00', 'date_of_expiration': None, 'expiration_date_from': None, 'expiration_date_to': None, 'expires': False, 'external_reference': '', 'id': '1968090813-569d7a93-43e4-4d12-8a56-737ca73e38da', 'init_point': 'https://www.mercadopago.com.br/checkout/v1/redirect?pref_id=1968090813-569d7a93-43e4-4d12-8a56-737ca73e38da', 'internal_metadata': None, 'items': [{'id': '', 'category_id': '', 'currency_id': 'BRL', 'description': '', 'title': 'Mi producto', 'quantity': 1, 'unit_price': 75.56}, {'id': '', 'category_id': '', 'currency_id': 'BRL', 'description': '', 'title': 'Mi producto2', 'quantity': 2, 'unit_price': 96.56}], 'marketplace': 'NONE', 'marketplace_fee': 0, 'metadata': {}, 'notification_url': None, 'operation_type': 'regular_payment', 'payer': {'phone': {'area_code': '', 'number': ''}, 'address': {'zip_code': '', 'street_name': '', 'street_number': None}, 'email': '', 'identification': {'number': '', 'type': ''}, 'name': '', 'surname': '', 'date_created': None, 'last_purchase': None}, 'payment_methods': {'default_card_id': None, 'default_payment_method_id': None, 'excluded_payment_methods': [{'id': ''}], 'excluded_payment_types': [{'id': ''}], 'installments': None, 'default_installments': None}, 'processing_modes': None, 'product_id': None, 'redirect_urls': {'failure': '', 'pending': '', 'success': ''}, 'sandbox_init_point': 'https://sandbox.mercadopago.com.br/checkout/v1/redirect?pref_id=1968090813-569d7a93-43e4-4d12-8a56-737ca73e38da', 'site_id': 'MLB', 'shipments': {'default_shipping_method': None, 'receiver_address': {'zip_code': '', 'street_name': '', 'street_number': None, 'floor': '', 'apartment': '', 'city_name': None, 'state_name': None, 'country_name': None}}, 'total_amount': None, 'last_updated': None, 'financing_group': ''}}

The key we are primarily interested in is 'init_point', which contains a URL for the payment page that the user will access.

Note that the payment details exhibited on the page are the ones contained in the preference_data dictionary.

Also, note we still need to finish some modifications for the payment system to be fully operational.