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package pay
import (
"crypto"
crand "crypto/rand"
"crypto/rsa"
"crypto/sha256"
"crypto/x509"
"encoding/base64"
"encoding/pem"
"errors"
"fmt"
mrand "math/rand"
"os"
"sync"
"time"
"bindbox-game/configs"
)
// 私钥缓存 - 避免每次请求都从磁盘读取
var (
cachedRSAKey *rsa.PrivateKey
rsaKeyOnce sync.Once
rsaKeyLoadErr error
rsaKeyConfigPath string // 记录加载时的路径,用于检测配置变更
)
// loadRSAPrivateKey 从磁盘加载私钥(内部函数,仅在首次调用时执行)
func loadRSAPrivateKey(keyPath string) (*rsa.PrivateKey, error) {
b, err := os.ReadFile(keyPath)
if err != nil {
return nil, err
}
block, _ := pem.Decode(b)
if block == nil {
return nil, errors.New("invalid merchant private key pem")
}
key, err := x509.ParsePKCS8PrivateKey(block.Bytes)
if err != nil {
// 兼容PKCS1
k1, e1 := x509.ParsePKCS1PrivateKey(block.Bytes)
if e1 != nil {
return nil, err
}
key = k1
}
rsaKey, ok := key.(*rsa.PrivateKey)
if !ok {
return nil, errors.New("merchant private key is not RSA")
}
return rsaKey, nil
}
// getCachedRSAKey 获取缓存的RSA私钥
func getCachedRSAKey(keyPath string) (*rsa.PrivateKey, error) {
rsaKeyOnce.Do(func() {
rsaKeyConfigPath = keyPath
cachedRSAKey, rsaKeyLoadErr = loadRSAPrivateKey(keyPath)
})
// 如果配置路径变更(理论上不应该发生),返回错误以提示重启
if rsaKeyConfigPath != keyPath {
return nil, errors.New("private key path changed, please restart the server")
}
return cachedRSAKey, rsaKeyLoadErr
}
// BuildJSAPIParams 为小程序支付构造客户端参数
// 入参appid(微信小程序AppID)、prepayID(统一下单返回的prepay_id)
// 返回timeStamp、nonceStr、package(格式为"prepay_id=***" )、signType(固定"RSA")、paySign(RSA-SHA256签名)
// 错误:当私钥读取或签名失败时返回错误
func BuildJSAPIParams(appid string, prepayID string) (timeStamp string, nonceStr string, pkg string, signType string, paySign string, err error) {
cfg := configs.Get()
if cfg.WechatPay.PrivateKeyPath == "" {
return "", "", "", "", "", errors.New("wechat pay private key path not configured")
}
// 使用缓存的私钥,避免每次都从磁盘读取
rsaKey, err := getCachedRSAKey(cfg.WechatPay.PrivateKeyPath)
if err != nil {
return "", "", "", "", "", err
}
ts := fmt.Sprintf("%d", time.Now().Unix())
// 随机串32位
const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
rb := make([]byte, 32)
for i := range rb {
rb[i] = letters[mrand.Intn(len(letters))]
}
nonce := string(rb)
pkg = "prepay_id=" + prepayID
signType = "RSA"
message := fmt.Sprintf("%s\n%s\n%s\n%s\n", appid, ts, nonce, pkg)
h := sha256.Sum256([]byte(message))
sig, err := rsa.SignPKCS1v15(crand.Reader, rsaKey, crypto.SHA256, h[:])
if err != nil {
return "", "", "", "", "", err
}
paySign = base64.StdEncoding.EncodeToString(sig)
return ts, nonce, pkg, signType, paySign, nil
}
// ValidateConfig 校验微信支付必要配置
// 入参:无
// 返回true表示配置齐全false表示缺失并附带错误信息
func ValidateConfig() (bool, error) {
c := configs.Get()
if c.Wechat.AppID == "" {
return false, errors.New("wechat app_id missing")
}
if c.WechatPay.MchID == "" || c.WechatPay.SerialNo == "" || c.WechatPay.PrivateKeyPath == "" || c.WechatPay.ApiV3Key == "" {
return false, errors.New("wechat pay config incomplete")
}
return true, nil
}