feat(api): add get transaction info api

Author: richzw

README.md

@@ -123,7 +123,7 @@ func main() {
 
 # Support
 
-App Store Server API [1.6](https://developer.apple.com/documentation/appstoreserverapi)
+App Store Server API [1.8](https://developer.apple.com/documentation/appstoreserverapi)
 
 # License
 

model.go

@@ -8,6 +8,11 @@ type OrderLookupResponse struct {
 	SignedTransactions []string `json:"signedTransactions"`
 }
 
+// TransactionInfoResponse https://developer.apple.com/documentation/appstoreserverapi/transactioninforesponse
+type TransactionInfoResponse struct {
+	SignedTransactionInfo string `json:"signedTransactionInfo"`
+}
+
 // HistoryResponse https://developer.apple.com/documentation/appstoreserverapi/historyresponse
 type HistoryResponse struct {
 	AppAppleId         int      `json:"appAppleId"`

store.go

@@ -21,6 +21,7 @@ const (
 	HostSandBox    = "https://api.storekit-sandbox.itunes.apple.com"
 	HostProduction = "https://api.storekit.itunes.apple.com"
 
+	PathTransactionInfo               = "/inApps/v1/transactions/{transactionId}"
 	PathLookUp                        = "/inApps/v1/lookup/{orderId}"
 	PathTransactionHistory            = "/inApps/v1/history/{originalTransactionId}"
 	PathRefundHistory                 = "/inApps/v2/refund/lookup/{originalTransactionId}"
@@ -113,6 +114,26 @@ func (c *StoreClient) GetALLSubscriptionStatuses(ctx context.Context, originalTr
 	return rsp, nil
 }
 
+// GetTransactionInfo https://developer.apple.com/documentation/appstoreserverapi/get_transaction_info
+func (c *StoreClient) GetTransactionInfo(ctx context.Context, transactionId string) (*TransactionInfoResponse, error) {
+	URL := c.hostUrl + PathTransactionInfo
+	URL = strings.Replace(URL, "{transactionId}", transactionId, -1)
+
+	var client HTTPClient
+	client = c.httpCli
+	client = SetInitializer(client, c.initHttpClient)
+	client = RequireResponseStatus(client, http.StatusOK)
+	client = SetRequest(ctx, client, http.MethodGet, URL)
+	rsp := &TransactionInfoResponse{}
+	client = SetResponseBodyHandler(client, json.Unmarshal, rsp)
+
+	_, err := client.Do(nil)
+	if err != nil {
+		return nil, err
+	}
+	return rsp, nil
+}
+
 // LookupOrderID https://developer.apple.com/documentation/appstoreserverapi/look_up_order_id
 func (c *StoreClient) LookupOrderID(ctx context.Context, orderId string) (*OrderLookupResponse, error) {
 	URL := c.hostUrl + PathLookUp