f

app/main/api/internal/service/wechatpayService.go

@@ -2,10 +2,16 @@ package service
 
 import (
 	"context"
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"encoding/base64"
 	"fmt"
 	"net/http"
 	"strconv"
 	"time"
+
 	"bdrp-server/app/main/api/internal/config"
 	"bdrp-server/app/main/model"
 	"bdrp-server/common/ctxdata"
@@ -151,11 +157,23 @@ func newWechatPayServiceWithWxPayPubKey(c config.Config, userAuthModel model.Use
 	}
 }
 
-// CreateWechatAppOrder 创建微信APP支付订单
-func (w *WechatPayService) CreateWechatAppOrder(ctx context.Context, amount float64, description string, outTradeNo string) (string, error) {
+// randomNonceWechat 生成微信调起支付用的随机串
+func randomNonceWechat(n int) (string, error) {
+	const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+	b := make([]byte, n)
+	if _, err := rand.Read(b); err != nil {
+		return "", err
+	}
+	for i := range b {
+		b[i] = letters[int(b[i])%len(letters)]
+	}
+	return string(b), nil
+}
+
+// CreateWechatAppOrder 创建微信 APP 支付：统一下单后按 V3「APP 调起支付」规则签名，供原生 SDK / uni.requestPayment(wxpay) 使用
+func (w *WechatPayService) CreateWechatAppOrder(ctx context.Context, amount float64, description string, outTradeNo string) (map[string]string, error) {
 	totalAmount := lzUtils.ToWechatAmount(amount)
 
-	// 构建支付请求参数
 	payRequest := app.PrepayRequest{
 		Appid:       core.String(w.config.Wxpay.AppID),
 		Mchid:       core.String(w.config.Wxpay.MchID),
@@ -167,17 +185,41 @@ func (w *WechatPayService) CreateWechatAppOrder(ctx context.Context, amount floa
 		},
 	}
 
-	// 初始化 AppApiService
 	svc := app.AppApiService{Client: w.wechatClient}
-
-	// 发起预支付请求
 	resp, result, err := svc.Prepay(ctx, payRequest)
 	if err != nil {
-		return "", fmt.Errorf("微信支付订单创建失败: %v, 状态码: %d", err, result.Response.StatusCode)
+		return nil, fmt.Errorf("微信支付订单创建失败: %v, 状态码: %d", err, result.Response.StatusCode)
 	}
 
-	// 返回预支付交易会话标识
-	return *resp.PrepayId, nil
+	prepayID := *resp.PrepayId
+	mchPrivateKey, err := utils.LoadPrivateKeyWithPath(w.config.Wxpay.MchPrivateKeyPath)
+	if err != nil {
+		return nil, fmt.Errorf("加载商户私钥失败: %w", err)
+	}
+
+	ts := strconv.FormatInt(time.Now().Unix(), 10)
+	nonceStr, err := randomNonceWechat(32)
+	if err != nil {
+		return nil, err
+	}
+
+	appID := w.config.Wxpay.AppID
+	msg := fmt.Sprintf("%s\n%s\n%s\n%s\n", appID, ts, nonceStr, prepayID)
+	sum := sha256.Sum256([]byte(msg))
+	sig, err := rsa.SignPKCS1v15(rand.Reader, mchPrivateKey, crypto.SHA256, sum[:])
+	if err != nil {
+		return nil, fmt.Errorf("APP 调起支付签名失败: %w", err)
+	}
+
+	return map[string]string{
+		"appid":     appID,
+		"partnerid": w.config.Wxpay.MchID,
+		"prepayid":  prepayID,
+		"package":   "Sign=WXPay",
+		"noncestr":  nonceStr,
+		"timestamp": ts,
+		"sign":      base64.StdEncoding.EncodeToString(sig),
+	}, nil
 }
 
 // CreateWechatMiniProgramOrder 创建微信小程序支付订单