Purpose

This page explains the Transfer module's asynchronous operation structure, the cart-addition process, and webhook communication traffic with external services.

🛣️ Transfer Services and Webhook Flows

Unlike the rental module, the Transfer module includes point-to-point pricing and custom route calculations. These processes are managed in a hybrid manner over AJAX and the REST API.

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🛒 1. Transfer Booking Flow (Frontend)

Customer-side interactions are executed via AJAX for high performance:

• Action: rentiva_transfer_add_to_cart
• Security: rentiva_transfer_nonce verification is required.
• Data Model: Added to the WooCommerce cart with a booking_type=transfer tag.
• Workflow: The selected vehicle type, passenger count, and route information are validated by TransferPricingEngine before being reflected in the cart.

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📡 2. Webhook and Callback Mechanism

Communication with external payment providers and transfer partners is handled via REST endpoints.

Payout and Booking Callback

• Route: /mhm-rentiva/v1/payouts/{id}/callback
• Verification: HMAC-SHA256-based signature check.
• Flow: After a "Success" signal is received from the payment service, TransferService confirms the booking and sends notifications to the relevant parties (Customer/Vendor).

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🏥 3. System Health Check (Health Endpoint)

Provides external observability (monitoring) of the system.

• URL: /wp-json/mhm-rentiva/v1/health
• Use Cases: Uptime monitoring, smoke testing, and post-CI/CD liveness checks.
• Returned Data: Status of database tables, /tmp directory write permissions, and PHP version compatibility.

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🛡️ 4. Security and Rate Limiting

• General Limit: 30 requests per minute for transfer search endpoints.
• Callback Limit: Custom limits are applied per PSP identity, not per IP.
• Idempotency: Repeated requests with the same notification ID are not processed, but 200 OK is returned.

Section Summary

• The Transfer module uses both AJAX (Frontend) and REST (Backend/External) layers together.
• All financial interactions are subject to signature-based (HMAC) verification.
• The Health endpoint allows real-time monitoring of the system's operational status.

Changelog

Date	Version	Note
23.04.2026	4.27.2	English translation added.
19.03.2026	4.21.2	TransferPricingEngine integration, Health endpoint details, and HMAC verification flow added.