EagleCast

internal/bounce/webhooks/forwardemail.go

@@ -0,0 +1,99 @@
+package webhooks
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	"source.offmarket.win/aleagle/eaglecast/models"
+)
+
+type BounceDetails struct {
+	Action   string `json:"action"`
+	Message  string `json:"message"`
+	Category string `json:"category"`
+	Code     int    `json:"code"`
+	Status   any    `json:"status"`
+	Line     int    `json:"line"`
+}
+
+type forwardemailNotif struct {
+	EmailID         string            `json:"email_id"`
+	ListID          string            `json:"list_id"`
+	ListUnsubscribe string            `json:"list_unsubscribe"`
+	FeedbackID      string            `json:"feedback_id"`
+	Recipient       string            `json:"recipient"`
+	Message         string            `json:"message"`
+	Response        string            `json:"response"`
+	ResponseCode    int               `json:"response_code"`
+	TruthSource     string            `json:"truth_source"`
+	Headers         map[string]string `json:"headers"`
+	Bounce          BounceDetails     `json:"bounce"`
+	BouncedAt       time.Time         `json:"bounced_at"`
+}
+
+// Forwardemail handles webhook notifications (mainly bounce notifications).
+type Forwardemail struct {
+	hmacKey []byte
+}
+
+func NewForwardemail(key []byte) *Forwardemail {
+	return &Forwardemail{hmacKey: key}
+}
+
+func (p *Forwardemail) ProcessBounce(sigHex string, body []byte) ([]models.Bounce, error) {
+	if len(p.hmacKey) == 0 {
+		return nil, errors.New("webhook key is not configured")
+	}
+
+	// Decode the hex-encoded signature from the webhook
+	sig, err := hex.DecodeString(sigHex)
+	if err != nil {
+		return nil, fmt.Errorf("invalid signature encoding: %v", err)
+	}
+
+	// Generate HMAC using the request body and secret key
+	mac := hmac.New(sha256.New, p.hmacKey)
+	mac.Write(body)
+	expectedSignature := mac.Sum(nil)
+
+	// Compare the generated signature with the provided signature
+	if !hmac.Equal(expectedSignature, sig) {
+		return nil, errors.New("invalid signature")
+	}
+
+	// Parse the JSON payload
+	var n forwardemailNotif
+	if err := json.Unmarshal(body, &n); err != nil {
+		return nil, fmt.Errorf("error unmarshalling Forwardemail notification: %v", err)
+	}
+
+	// Categorize the bounce type
+	typ := models.BounceTypeSoft
+	hardBounceCategories := []string{"block", "recipient", "virus", "spam"}
+	for _, category := range hardBounceCategories {
+		if n.Bounce.Category == category {
+			typ = models.BounceTypeHard
+			break
+		}
+	}
+
+	campUUID := ""
+	if v, ok := n.Headers["X-EagleCast-Campaign"]; ok {
+		campUUID = v
+	}
+
+	return []models.Bounce{{
+		Email:        strings.ToLower(n.Recipient),
+		CampaignUUID: campUUID,
+		Type:         typ,
+		Source:       "forwardemail",
+		Meta:         json.RawMessage(body),
+		CreatedAt:    n.BouncedAt,
+	}}, nil
+}