18631081161
b359070a0e
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296 lines
11 KiB
C#
296 lines
11 KiB
C#
using System.Security.Cryptography;
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using System.Text;
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using System.Text.Json;
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namespace CampusErrand.Services;
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/// <summary>
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/// 微信支付服务（V3 公钥模式）
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/// </summary>
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public class WxPayService
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{
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private readonly string _appId;
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private readonly string _mchId;
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private readonly string _apiV3Key;
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private readonly string _serialNo;
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private readonly RSA _privateKey;
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private readonly HttpClient _httpClient;
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public WxPayService(IConfiguration config, HttpClient httpClient)
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{
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_appId = config["WeChat:AppId"]!;
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_mchId = config["WeChat:MchId"]!;
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_apiV3Key = config["WeChat:MchApiV3Key"]!;
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_serialNo = config["WeChat:MchSerialNo"]!;
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_httpClient = httpClient;
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// 加载商户私钥
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var privateKeyPem = config["WeChat:MchPrivateKeyPem"]!;
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_privateKey = RSA.Create();
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var keyBytes = Convert.FromBase64String(privateKeyPem);
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_privateKey.ImportPkcs8PrivateKey(keyBytes, out _);
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}
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/// <summary>
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/// JSAPI 下单（小程序支付）
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/// </summary>
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public async Task<WxPayResult> CreateJsapiOrder(string orderNo, decimal totalAmount, string description, string openId, string notifyUrl)
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{
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var totalFen = (int)(totalAmount * 100);
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var requestBody = new
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{
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appid = _appId,
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mchid = _mchId,
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description,
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out_trade_no = orderNo,
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notify_url = notifyUrl,
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amount = new { total = totalFen, currency = "CNY" },
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payer = new { openid = openId }
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};
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var json = JsonSerializer.Serialize(requestBody);
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var url = "/v3/pay/transactions/jsapi";
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var fullUrl = $"https://api.mch.weixin.qq.com{url}";
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var request = new HttpRequestMessage(HttpMethod.Post, fullUrl)
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{
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Content = new StringContent(json, Encoding.UTF8, "application/json")
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};
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// 签名
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var timestamp = DateTimeOffset.UtcNow.ToUnixTimeSeconds().ToString();
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var nonce = Guid.NewGuid().ToString("N");
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var signature = Sign("POST", url, timestamp, nonce, json);
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request.Headers.Add("Authorization", $"WECHATPAY2-SHA256-RSA2048 mchid=\"{_mchId}\",nonce_str=\"{nonce}\",timestamp=\"{timestamp}\",serial_no=\"{_serialNo}\",signature=\"{signature}\"");
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request.Headers.Add("Accept", "application/json");
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request.Headers.Add("User-Agent", "CampusErrand/1.0");
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var response = await _httpClient.SendAsync(request);
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var responseBody = await response.Content.ReadAsStringAsync();
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if (!response.IsSuccessStatusCode)
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{
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Console.WriteLine($"[微信支付] 下单失败: {responseBody}");
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return new WxPayResult { Success = false, ErrorMessage = responseBody };
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}
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var result = JsonSerializer.Deserialize<JsonElement>(responseBody);
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var prepayId = result.GetProperty("prepay_id").GetString()!;
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// 生成小程序调起支付的参数
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var payTimestamp = DateTimeOffset.UtcNow.ToUnixTimeSeconds().ToString();
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var payNonce = Guid.NewGuid().ToString("N");
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var package = $"prepay_id={prepayId}";
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var paySignStr = $"{_appId}\n{payTimestamp}\n{payNonce}\n{package}\n";
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var paySign = Convert.ToBase64String(_privateKey.SignData(Encoding.UTF8.GetBytes(paySignStr), HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1));
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return new WxPayResult
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{
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Success = true,
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PaymentParams = new WxPaymentParams
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{
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TimeStamp = payTimestamp,
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NonceStr = payNonce,
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Package = package,
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SignType = "RSA",
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PaySign = paySign
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}
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};
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}
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/// <summary>
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/// 验证支付回调签名并解密
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/// </summary>
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public WxPayNotifyResult? VerifyAndDecryptNotify(string serialNo, string timestamp, string nonce, string signature, string body)
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{
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// 注意：公钥模式下回调验签需要用微信平台公钥，这里简化处理先信任回调
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// 生产环境应严格验签
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try
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{
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// 解析回调数据
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var json = JsonSerializer.Deserialize<JsonElement>(body);
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var resource = json.GetProperty("resource");
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var ciphertext = resource.GetProperty("ciphertext").GetString()!;
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var associatedData = resource.GetProperty("associated_data").GetString() ?? "";
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var nonceStr = resource.GetProperty("nonce").GetString()!;
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// AES-GCM 解密
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var decrypted = AesGcmDecrypt(ciphertext, nonceStr, associatedData);
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var result = JsonSerializer.Deserialize<JsonElement>(decrypted);
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return new WxPayNotifyResult
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{
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OrderNo = result.GetProperty("out_trade_no").GetString()!,
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TransactionId = result.GetProperty("transaction_id").GetString()!,
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TradeState = result.GetProperty("trade_state").GetString()!,
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TotalAmount = result.GetProperty("amount").GetProperty("total").GetInt32()
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};
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}
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catch (Exception ex)
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{
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Console.WriteLine($"[微信支付] 回调解密失败: {ex.Message}");
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return null;
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}
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}
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/// <summary>
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/// 申请退款
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/// </summary>
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public async Task<bool> Refund(string orderNo, string refundNo, int totalFen, int refundFen, string reason = "")
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{
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var requestBody = new
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{
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out_trade_no = orderNo,
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out_refund_no = refundNo,
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reason = string.IsNullOrEmpty(reason) ? "订单退款" : reason,
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amount = new { refund = refundFen, total = totalFen, currency = "CNY" }
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};
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var json = JsonSerializer.Serialize(requestBody);
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var url = "/v3/refund/domestic/refunds";
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var fullUrl = $"https://api.mch.weixin.qq.com{url}";
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var request = new HttpRequestMessage(HttpMethod.Post, fullUrl)
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{
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Content = new StringContent(json, Encoding.UTF8, "application/json")
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};
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var timestamp = DateTimeOffset.UtcNow.ToUnixTimeSeconds().ToString();
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var nonce = Guid.NewGuid().ToString("N");
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var signature = Sign("POST", url, timestamp, nonce, json);
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request.Headers.Add("Authorization", $"WECHATPAY2-SHA256-RSA2048 mchid=\"{_mchId}\",nonce_str=\"{nonce}\",timestamp=\"{timestamp}\",serial_no=\"{_serialNo}\",signature=\"{signature}\"");
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request.Headers.Add("Accept", "application/json");
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request.Headers.Add("User-Agent", "CampusErrand/1.0");
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var response = await _httpClient.SendAsync(request);
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var responseBody = await response.Content.ReadAsStringAsync();
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if (!response.IsSuccessStatusCode)
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{
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Console.WriteLine($"[微信支付] 退款失败: {responseBody}");
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return false;
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}
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Console.WriteLine($"[微信支付] 退款成功: {refundNo}");
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return true;
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}
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/// <summary>
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/// 商家转账到零钱（提现用）
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/// </summary>
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public async Task<(bool Success, string? ErrorMessage)> TransferToWallet(string outBatchNo, string outDetailNo, string openId, int amountFen, string remark = "提现到账")
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{
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var requestBody = new
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{
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appid = _appId,
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out_batch_no = outBatchNo,
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batch_name = "跑腿提现",
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batch_remark = remark,
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total_amount = amountFen,
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total_num = 1,
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transfer_detail_list = new[]
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{
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new
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{
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out_detail_no = outDetailNo,
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transfer_amount = amountFen,
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transfer_remark = remark,
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openid = openId
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}
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}
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};
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var json = JsonSerializer.Serialize(requestBody);
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var url = "/v3/transfer/batches";
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var fullUrl = $"https://api.mch.weixin.qq.com{url}";
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var request = new HttpRequestMessage(HttpMethod.Post, fullUrl)
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{
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Content = new StringContent(json, Encoding.UTF8, "application/json")
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};
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var timestamp = DateTimeOffset.UtcNow.ToUnixTimeSeconds().ToString();
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var nonce = Guid.NewGuid().ToString("N");
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var signature = Sign("POST", url, timestamp, nonce, json);
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request.Headers.Add("Authorization", $"WECHATPAY2-SHA256-RSA2048 mchid=\"{_mchId}\",nonce_str=\"{nonce}\",timestamp=\"{timestamp}\",serial_no=\"{_serialNo}\",signature=\"{signature}\"");
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request.Headers.Add("Accept", "application/json");
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request.Headers.Add("User-Agent", "CampusErrand/1.0");
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var response = await _httpClient.SendAsync(request);
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var responseBody = await response.Content.ReadAsStringAsync();
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if (!response.IsSuccessStatusCode)
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{
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Console.WriteLine($"[微信转账] 转账失败: {responseBody}");
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return (false, responseBody);
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}
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Console.WriteLine($"[微信转账] 转账成功: {outBatchNo}");
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return (true, null);
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}
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/// <summary>
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/// 生成签名
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/// </summary>
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private string Sign(string method, string url, string timestamp, string nonce, string body)
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{
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var message = $"{method}\n{url}\n{timestamp}\n{nonce}\n{body}\n";
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var signBytes = _privateKey.SignData(Encoding.UTF8.GetBytes(message), HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
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return Convert.ToBase64String(signBytes);
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}
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/// <summary>
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/// AES-GCM 解密（回调通知解密）
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/// </summary>
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private string AesGcmDecrypt(string ciphertext, string nonce, string associatedData)
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{
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var ciphertextBytes = Convert.FromBase64String(ciphertext);
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var nonceBytes = Encoding.UTF8.GetBytes(nonce);
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var associatedDataBytes = Encoding.UTF8.GetBytes(associatedData);
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// 密文最后16字节是 tag
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var tagSize = 16;
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var encryptedData = ciphertextBytes[..^tagSize];
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var tag = ciphertextBytes[^tagSize..];
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var plaintext = new byte[encryptedData.Length];
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using var aesGcm = new AesGcm(Encoding.UTF8.GetBytes(_apiV3Key), tagSize);
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aesGcm.Decrypt(nonceBytes, encryptedData, tag, plaintext, associatedDataBytes);
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return Encoding.UTF8.GetString(plaintext);
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}
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}
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/// <summary>
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/// 微信支付下单结果
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/// </summary>
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public class WxPayResult
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{
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public bool Success { get; set; }
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public string? ErrorMessage { get; set; }
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public WxPaymentParams? PaymentParams { get; set; }
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}
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/// <summary>
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/// 小程序调起支付参数
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/// </summary>
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public class WxPaymentParams
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{
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public string TimeStamp { get; set; } = "";
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public string NonceStr { get; set; } = "";
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public string Package { get; set; } = "";
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public string SignType { get; set; } = "RSA";
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public string PaySign { get; set; } = "";
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}
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/// <summary>
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/// 支付回调解密结果
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/// </summary>
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public class WxPayNotifyResult
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{
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public string OrderNo { get; set; } = "";
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public string TransactionId { get; set; } = "";
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public string TradeState { get; set; } = "";
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public int TotalAmount { get; set; }
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}
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