feat(api): add ParseNotificationV2 to parse notification v2 body

Author: richzw

cert.go

@@ -1,10 +1,12 @@
 package appstore
 
 import (
+	"crypto/ecdsa"
 	"crypto/x509"
 	"encoding/base64"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"strings"
 )
 
@@ -92,3 +94,42 @@ func (c *Cert) verifyCert(rootCert, intermediaCert, leafCert *x509.Certificate)
 
 	return nil
 }
+
+func (c *Cert) extractPublicKeyFromToken(token string) (*ecdsa.PublicKey, error) {
+	rootCertBytes, err := c.extractCertByIndex(token, 2)
+	if err != nil {
+		return nil, err
+	}
+	rootCert, err := x509.ParseCertificate(rootCertBytes)
+	if err != nil {
+		return nil, fmt.Errorf("appstore failed to parse root certificate")
+	}
+
+	intermediaCertBytes, err := c.extractCertByIndex(token, 1)
+	if err != nil {
+		return nil, err
+	}
+	intermediaCert, err := x509.ParseCertificate(intermediaCertBytes)
+	if err != nil {
+		return nil, fmt.Errorf("appstore failed to parse intermediate certificate")
+	}
+
+	leafCertBytes, err := c.extractCertByIndex(token, 0)
+	if err != nil {
+		return nil, err
+	}
+	leafCert, err := x509.ParseCertificate(leafCertBytes)
+	if err != nil {
+		return nil, fmt.Errorf("appstore failed to parse leaf certificate")
+	}
+	if err = c.verifyCert(rootCert, intermediaCert, leafCert); err != nil {
+		return nil, err
+	}
+
+	switch pk := leafCert.PublicKey.(type) {
+	case *ecdsa.PublicKey:
+		return pk, nil
+	default:
+		return nil, errors.New("appstore public key must be of type ecdsa.PublicKey")
+	}
+}

model.go

@@ -1,5 +1,7 @@
 package appstore
 
+import "github.com/golang-jwt/jwt/v4"
+
 // OrderLookupResponse https://developer.apple.com/documentation/appstoreserverapi/orderlookupresponse
 type OrderLookupResponse struct {
 	Status             int      `json:"status"`
@@ -196,3 +198,55 @@ const (
 type SendTestNotificationResponse struct {
 	TestNotificationToken string `json:"testNotificationToken"`
 }
+
+// Notification signed payload
+type NotificationPayload struct {
+	jwt.RegisteredClaims
+	NotificationType    string           `json:"notificationType"`
+	Subtype             string           `json:"subtype"`
+	NotificationUUID    string           `json:"notificationUUID"`
+	NotificationVersion string           `json:"notificationVersion"`
+	Data                NotificationData `json:"data"`
+}
+
+// Notification Data
+type NotificationData struct {
+	jwt.RegisteredClaims
+	AppAppleID            int    `json:"appAppleId"`
+	BundleID              string `json:"bundleId"`
+	BundleVersion         string `json:"bundleVersion"`
+	Environment           string `json:"environment"`
+	SignedRenewalInfo     string `json:"signedRenewalInfo"`
+	SignedTransactionInfo string `json:"signedTransactionInfo"`
+}
+
+// Notification Transaction Info
+type TransactionInfo struct {
+	jwt.RegisteredClaims
+	TransactionId               string `json:"transactionId"`
+	OriginalTransactionID       string `json:"originalTransactionId"`
+	WebOrderLineItemID          string `json:"webOrderLineItemId"`
+	BundleID                    string `json:"bundleId"`
+	ProductID                   string `json:"productId"`
+	SubscriptionGroupIdentifier string `json:"subscriptionGroupIdentifier"`
+	PurchaseDate                int    `json:"purchaseDate"`
+	OriginalPurchaseDate        int    `json:"originalPurchaseDate"`
+	ExpiresDate                 int    `json:"expiresDate"`
+	Type                        string `json:"type"`
+	InAppOwnershipType          string `json:"inAppOwnershipType"`
+	SignedDate                  int    `json:"signedDate"`
+	Environment                 string `json:"environment"`
+}
+
+// Notification Renewal Info
+type RenewalInfo struct {
+	jwt.RegisteredClaims
+	OriginalTransactionID  string `json:"originalTransactionId"`
+	ExpirationIntent       int    `json:"expirationIntent"`
+	AutoRenewProductId     string `json:"autoRenewProductId"`
+	ProductID              string `json:"productId"`
+	AutoRenewStatus        int    `json:"autoRenewStatus"`
+	IsInBillingRetryPeriod bool   `json:"isInBillingRetryPeriod"`
+	SignedDate             int    `json:"signedDate"`
+	Environment            string `json:"environment"`
+}

store.go

@@ -304,6 +304,12 @@ func (c *StoreClient) GetTestNotificationStatus(ctx context.Context, testNotific
 	return c.Do(ctx, http.MethodGet, URL, nil)
 }
 
+func (c *StoreClient) ParseNotificationV2(tokenStr string) (*jwt.Token, error) {
+	return jwt.Parse(tokenStr, func(token *jwt.Token) (interface{}, error) {
+		return c.cert.extractPublicKeyFromToken(tokenStr)
+	})
+}
+
 // ParseSignedTransactions parse the jws singed transactions
 // Per doc: https://datatracker.ietf.org/doc/html/rfc7515#section-4.1.6
 func (c *StoreClient) ParseSignedTransactions(transactions []string) ([]*JWSTransaction, error) {