refactor(webhooks): use a secure unified webhook handler

Author: malwarebo

api/webhook_handler.go

@@ -0,0 +1,135 @@
+package api
+
+import (
+	"encoding/json"
+	"io"
+	"net/http"
+	"time"
+
+	"github.com/gorilla/mux"
+	"github.com/malwarebo/gopay/providers"
+)
+
+type WebhookHandler struct {
+	stripeProvider *providers.StripeProvider
+	xenditProvider *providers.XenditProvider
+}
+
+func CreateWebhookHandler(stripeProvider *providers.StripeProvider, xenditProvider *providers.XenditProvider) *WebhookHandler {
+	return &WebhookHandler{
+		stripeProvider: stripeProvider,
+		xenditProvider: xenditProvider,
+	}
+}
+
+func (h *WebhookHandler) HandleStripeWebhook(w http.ResponseWriter, r *http.Request) {
+	payload, err := io.ReadAll(r.Body)
+	if err != nil {
+		http.Error(w, "Failed to read webhook payload", http.StatusBadRequest)
+		return
+	}
+
+	signature := r.Header.Get("Stripe-Signature")
+	if signature == "" {
+		http.Error(w, "Missing Stripe signature", http.StatusUnauthorized)
+		return
+	}
+
+	if err := h.stripeProvider.ValidateWebhookSignature(payload, signature); err != nil {
+		http.Error(w, "Invalid webhook signature", http.StatusUnauthorized)
+		return
+	}
+
+	var event map[string]interface{}
+	if err := json.Unmarshal(payload, &event); err != nil {
+		http.Error(w, "Invalid webhook payload", http.StatusBadRequest)
+		return
+	}
+
+	eventType, ok := event["type"].(string)
+	if !ok {
+		http.Error(w, "Missing event type", http.StatusBadRequest)
+		return
+	}
+
+	h.processStripeEvent(eventType, event)
+
+	response := map[string]interface{}{
+		"received":   true,
+		"event_type": eventType,
+		"timestamp":  time.Now(),
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	json.NewEncoder(w).Encode(response)
+}
+
+func (h *WebhookHandler) HandleXenditWebhook(w http.ResponseWriter, r *http.Request) {
+	payload, err := io.ReadAll(r.Body)
+	if err != nil {
+		http.Error(w, "Failed to read webhook payload", http.StatusBadRequest)
+		return
+	}
+
+	signature := r.Header.Get("x-callback-token")
+	if signature == "" {
+		http.Error(w, "Missing Xendit signature", http.StatusUnauthorized)
+		return
+	}
+
+	if err := h.xenditProvider.ValidateWebhookSignature(payload, signature); err != nil {
+		http.Error(w, "Invalid webhook signature", http.StatusUnauthorized)
+		return
+	}
+
+	var event map[string]interface{}
+	if err := json.Unmarshal(payload, &event); err != nil {
+		http.Error(w, "Invalid webhook payload", http.StatusBadRequest)
+		return
+	}
+
+	eventType, ok := event["event"].(string)
+	if !ok {
+		eventType = "unknown"
+	}
+
+	h.processXenditEvent(eventType, event)
+
+	response := map[string]interface{}{
+		"received":   true,
+		"event_type": eventType,
+		"timestamp":  time.Now(),
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	json.NewEncoder(w).Encode(response)
+}
+
+func (h *WebhookHandler) processStripeEvent(eventType string, event map[string]interface{}) {
+	switch eventType {
+	case "payment_intent.succeeded":
+	case "payment_intent.payment_failed":
+	case "payment_intent.requires_action":
+	case "payment_intent.canceled":
+	case "charge.refunded":
+	case "charge.dispute.created":
+	default:
+	}
+}
+
+func (h *WebhookHandler) processXenditEvent(eventType string, event map[string]interface{}) {
+	switch eventType {
+	case "payment.succeeded":
+	case "payment.failed":
+	case "payment.pending":
+	case "refund.succeeded":
+	default:
+	}
+}
+
+func (h *WebhookHandler) RegisterRoutes(router *mux.Router) {
+	router.HandleFunc("/webhooks/stripe", h.HandleStripeWebhook).Methods("POST")
+	router.HandleFunc("/webhooks/xendit", h.HandleXenditWebhook).Methods("POST")
+}