优化结构

pkg/paymentkit/callback.go

@@ -0,0 +1,91 @@
+package paymentutil
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+)
+
+const (
+	ProviderAlipay   = "alipay"
+	ProviderAlipayV3 = "alipay-v3"
+	ProviderWechatV2 = "wechat-v2"
+	ProviderWechatV3 = "wechat-v3"
+	ProviderApple    = "apple-iap"
+)
+
+// CallbackAck is the provider-facing HTTP acknowledgement returned after a
+// payment notification is processed.
+type CallbackAck struct {
+	StatusCode  int
+	ContentType string
+	Body        []byte
+}
+
+// CallbackError carries a safe provider acknowledgement alongside the cause
+// that should be logged or returned to the application layer.
+type CallbackError struct {
+	Cause error
+	Ack   CallbackAck
+}
+
+func (e *CallbackError) Error() string {
+	if e == nil || e.Cause == nil {
+		return "支付回调处理失败"
+	}
+	return e.Cause.Error()
+}
+
+func (e *CallbackError) Unwrap() error {
+	if e == nil {
+		return nil
+	}
+	return e.Cause
+}
+
+func CallbackFailure(err error, fallback CallbackAck) CallbackAck {
+	var callbackErr *CallbackError
+	if errors.As(err, &callbackErr) && callbackErr.Ack.StatusCode != 0 {
+		return callbackErr.Ack
+	}
+	return fallback
+}
+
+// DefaultCallbackAck returns the conventional acknowledgement for providers
+// whose callback wire formats are stable across modules.
+func DefaultCallbackAck(provider string, success bool) CallbackAck {
+	status := 200
+	if !success {
+		status = 500
+	}
+	switch provider {
+	case ProviderAlipay, ProviderAlipayV3:
+		body := "success"
+		if !success {
+			body = "failure"
+		}
+		return CallbackAck{StatusCode: status, ContentType: "text/plain; charset=utf-8", Body: []byte(body)}
+	case ProviderWechatV2:
+		code, message := "SUCCESS", "OK"
+		if !success {
+			code, message = "FAIL", "FAIL"
+		}
+		body := fmt.Sprintf("<xml><return_code><![CDATA[%s]]></return_code><return_msg><![CDATA[%s]]></return_msg></xml>", code, message)
+		return CallbackAck{StatusCode: status, ContentType: "application/xml; charset=utf-8", Body: []byte(body)}
+	case ProviderWechatV3:
+		code, message := "SUCCESS", "成功"
+		if !success {
+			code, message = "FAIL", "失败"
+		}
+		body, _ := json.Marshal(map[string]string{"code": code, "message": message})
+		return CallbackAck{StatusCode: status, ContentType: "application/json; charset=utf-8", Body: body}
+	case ProviderApple:
+		return CallbackAck{StatusCode: status}
+	default:
+		body := "success"
+		if !success {
+			body = "failure"
+		}
+		return CallbackAck{StatusCode: status, ContentType: "text/plain; charset=utf-8", Body: []byte(body)}
+	}
+}