.NetCore微信服务商二次进件

最近商城进行微信服务商二次进件的开发，大致有几个点

一，服务商签名

二，服务商证书获取

三，图片上传

四，敏感信息加密

五，查询进件状态

除此之外，就是进件信息的拼装

 电商二级商户进件申请单-状态流转

一 服务商签名

首先准备必须的配置：商户号、证书、秘钥、小程序appid、appsecret

#region 服务商签名
private string SrvPayBuildAuthAsync(string uri, string body, string method = "POST")
{
var timestamp = DateTimeOffset.Now.ToUnixTimeSeconds();
string nOnce= Guid.NewGuid().ToString();
string message = $"{method}\n{uri}\n{timestamp}\n{nonce}\n{body}\n";
string signature = SrvSign(message);
return $"mchid=\"{_wxCfg.SrvPayMerchantId}\",nonce_str=\"{nonce}\",timestamp=\"{timestamp}\",serial_no=\"{_wxCfg.SrvPayCertNo}\",signature=\"{signature}\"";
}
private string SrvSign(string message)
{
var bytes = Utils.ReadBytesIfExist(_wxCfg.SrvPayCertFile);
if (bytes is null)
{
return "";
}
X509Certificate2 cert = new(bytes, _wxCfg.SrvPayMerchantId);
RSA rsa = cert.GetRSAPrivateKey();
var signData = rsa.SignData(Encoding.UTF8.GetBytes(message), HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
return Convert.ToBase64String(signData);
}

二 获取证书

分为：第一步获取证书，第二步解密证书

1 获取证书

https://api.mch.weixin.qq.com/v3/certificates

#region 获取平台证书
public async Task GetSrvCert()
{
string uri = "/v3/certificates";
var auth = SrvPayBuildAuthAsync(uri, "", "GET");
var header = new Dictionary<string, string>
{
{ "Authorization",$"WECHATPAY2-SHA256-RSA2048 {auth}"},
{ "Accept","*/*" },
{ "Accept-Encoding","gzip,deflate,brn" },
{ "User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.85 Safari/537.36 Edg/90.0.818.46" },
};
return await GetUrlAsync(uri, header);
}
#endregion

使用的实体：CertificatesOutModel

public sealed class CertificatesOutModel : IWXResponse
{
[JsonPropertyName("data")]
public IEnumerable Data { get; set; }
public string Code { get; set; }
public string Message { get; set; }
}
public class Certificates
{
[JsonPropertyName("serial_no")]
public string SerialNo { get; set; }
[JsonPropertyName("effective_time")]
public string EffectiveTime { get; set; }
[JsonPropertyName("expire_time")]
public string ExpireTime { get; set; }
[JsonPropertyName("encrypt_certificate")]
public EncryptCertificate EncryptCertificate { get; set; }
}

请求方法：GetUrlAsync

protected async Task GetUrlAsync(string url, Dictionary<string, string> headers = null)
{
HttpResponseMessage res = null;
try
{
if (headers != null && headers.Count > 0)
{
foreach (var header in headers)
{
_client.DefaultRequestHeaders.TryAddWithoutValidation(header.Key, header.Value);
}
}
res = await _client.GetAsync(url);
res.EnsureSuccessStatusCode();
var result = await res.Content.ReadAsStringAsync();
if (result == null)
{
return default;
}
return result.ToJson();
}
catch
{
var result = await res.Content.ReadAsStringAsync();
if (result == null)
{
return default;
}
return result.ToJson();
}
}

2，解密证书

//获取证书
var cert = await _wxClient.GetSrvCert();
var certificateModel = cert.Data.FirstOrDefault();
if (!cert.Data.Any())
{
return new MKResult(code: 400, msg: "未获取到平台证书");
}
if (!string.IsNullOrEmpty(applyment.Body.SerialNo))
{
certificateModel = cert.Data.SingleOrDefault(s => s.SerialNo == applyment.Body.SerialNo);
}
certificateModel.EncryptCertificate.Ciphertext = AESUtility.AesGcmDecrypt(
_wxCfg.SrvApiV3Key,
certificateModel.EncryptCertificate.AssociatedData,
certificateModel.EncryptCertificate.Nonce,
certificateModel.EncryptCertificate.Ciphertext
);

解密方法

public class AESUtility
{
public static string AesGcmDecrypt(string key, string associatedData, string nonce, string ciphertext)
{
GcmBlockCipher gcmBlockCipher = new(new AesEngine());
AeadParameters aeadParameters = new(
new KeyParameter(Encoding.UTF8.GetBytes(key)),
128,
Encoding.UTF8.GetBytes(nonce),
Encoding.UTF8.GetBytes(associatedData));
gcmBlockCipher.Init(false, aeadParameters);
byte[] data = Convert.FromBase64String(ciphertext);
byte[] plaintext = new byte[gcmBlockCipher.GetOutputSize(data.Length)];
int length = gcmBlockCipher.ProcessBytes(data, 0, data.Length, plaintext, 0);
gcmBlockCipher.DoFinal(plaintext, length);
return Encoding.UTF8.GetString(plaintext);
}
}

三，上传图片

因为我的图片保存在oss，首先要网络图片Bytes，对图片进行sha256，方法在后面

protected async Task<byte[]> GetUrlBytesAsync(string url, Dictionary<string, string> headers = null)
{
try
{
if (headers != null && headers.Count > 0)
{
foreach (var header in headers)
{
_client.DefaultRequestHeaders.TryAddWithoutValidation(header.Key, header.Value);
}
}
var res = await _client.GetAsync(url);
res.EnsureSuccessStatusCode();
return await res.Content.ReadAsByteArrayAsync();
}
catch
{
return default;
}
}

然后上传图片

///