微信支付v3版本NET 图片上传API

最近在写特约服务商进件的由于微信官方没有DEMO，导致踩了很多坑，特把自己经验分享给大家。

注意几点：

1、上传图片签名不是把所有body内容都进行签名，只需签名计算的请求主体为meta的json串：{ "filename": "filea.jpg", "sha256": "hjkahkjsjkfsjk78687dhjahdajhk" }

2、签名的是私钥，私钥不包括私钥文件起始的-----BEGIN PRIVATE KEY----- 亦不包括结尾的-----END PRIVATE KEY-----

3、上传参数meta、file、文件名必须新增双引号

4、MultipartFormDataContent 必须添加头文件multipart/form-data，不然一直签名错误。

5、头文件必须添加"user-agent"、"application/json“

代码如下：

上传代码：

         string private_key = @"商户私钥";

            string mchid = "商户号";

            string serialNo = "商户API证书序列号";

            string filePath = @"H:\1.jpg";

            string boundary = string.Format("--{0}", DateTime.Now.Ticks.ToString("x"));

            var sha256 = SHAFile.SHA256File(filePath);

            meta meta = new meta()

            {

                sha256 = sha256,

                filename = System.IO.Path.GetFileName(serialNo)

            };

            var json = JsonConvert.SerializeObject(meta);

            var httpHandler = new HttpHandler(mchid, serialNo, private_key, json);

            HttpClient client = new HttpClient(httpHandler);

            using (var requestContent = new MultipartFormDataContent(boundary))

            {

                requestContent.Headers.ContentType = MediaTypeHeaderValue.Parse("multipart/form-data"); //这里必须添加

                requestContent.Add(new StringContent(json, Encoding.UTF8, "application/json"), "\"meta\""); //这里主要必须要双引号

                var fileInfo = new FileInfo(filePath);

                using (var fileStream = fileInfo.OpenRead())

                {

                    var content = new byte[fileStream.Length];

                    fileStream.Read(content, , content.Length);

                    var byteArrayContent = new ByteArrayContent(content);

                    byteArrayContent.Headers.ContentType = new MediaTypeHeaderValue("image/jpg");

                    requestContent.Add(byteArrayContent, "\"file\"", "\"" + meta.filename + "\"");  //这里主要必须要双引号

                    using (var response = await client.PostAsync("https://api.mch.weixin.qq.com/v3/merchant/media/upload", requestContent)) //上传

                    using (var responseContent = response.Content)

                    {

                        string responseBody = await responseContent.ReadAsStringAsync(); //这里就可以拿到图片id了

                        return ResultHelper.QuickReturn(responseBody);

                    }

                }

            }

SHAFile 类：

using System;

using System.Collections.Generic;

using System.IO;

using System.Security.Cryptography;

using System.Text;

namespace Cloud.Pay.Common

{

    public class SHAFile

    {

        /// 计算文件的 SHA256 值

        /// </summary>

        /// <param name="fileName">要计算 SHA256 值的文件名和路径</param>

        /// <returns>SHA256值16进制字符串</returns>

        public static string SHA256File(string fileName)

        {

            return HashFile(fileName, "sha256");

        }

        /// <summary>

        /// 计算文件的哈希值

        /// </summary>

        /// <param name="fileName">要计算哈希值的文件名和路径</param>

        /// <param name="algName">算法:sha1,md5</param>

        /// <returns>哈希值16进制字符串</returns>

        private static string HashFile(string fileName, string algName)

        {

            if (!System.IO.File.Exists(fileName))

                return string.Empty;

            FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);

            byte[] hashBytes = HashData(fs, algName);

            fs.Close();

            return ByteArrayToHexString(hashBytes);

        }

        /// <summary>

        /// 字节数组转换为16进制表示的字符串

        /// </summary>

        private static string ByteArrayToHexString(byte[] buf)

        {

            string returnStr = "";

            if (buf != null)

            {

                for (int i = ; i < buf.Length; i++)

                {

                    returnStr += buf[i].ToString("X2");

                }

            }

            return returnStr;

        }

        /// <summary>

        /// 计算哈希值

        /// </summary>

        /// <param name="stream">要计算哈希值的 Stream</param>

        /// <param name="algName">算法:sha1,md5</param>

        /// <returns>哈希值字节数组</returns>

        private static byte[] HashData(Stream stream, string algName)

        {

            HashAlgorithm algorithm;

            if (algName == null)

            {

                throw new ArgumentNullException("algName 不能为 null");

            }

            if (string.Compare(algName, "sha256", true) == )

            {

                algorithm = SHA256.Create();

            }

            else

            {

                if (string.Compare(algName, "md5", true) != )

                {

                    throw new Exception("algName 只能使用 sha256 或 md5");

                }

                algorithm = MD5.Create();

            }

            return algorithm.ComputeHash(stream);

        }

    }

}

meta类:

 public class meta

    {

        public string filename { get; set; }

        public string sha256 { get; set; }

    }

头文件

using System;

using System.IO;

using System.Net.Http;

using System.Net.Http.Headers;

using System.Security.Authentication;

using System.Security.Cryptography;

using System.Security.Cryptography.X509Certificates;

using System.Text;

using System.Threading;

using System.Threading.Tasks;

namespace Cloud.Pay.Common

{

    /// <summary>

    /// 头文件

    /// </summary>

    public class HttpHandler : DelegatingHandler

    {

        private readonly string merchantId;

        private readonly string serialNo;

        private readonly string privateKey;

        private readonly string json;

        /// <summary>

        /// 构造方法

        /// </summary>

        /// <param name="merchantId">商户号</param>

        /// <param name="merchantSerialNo">证书序列号</param>

        /// <param name="privateKey"> 私钥不包括私钥文件起始的-----BEGIN PRIVATE KEY-----        亦不包括结尾的-----END PRIVATE KEY-----</param>

        /// <param name="json">签名json数据,默认不需要传入，获取body内容，如传入签名传入参数上传图片时需传入</param>

        public HttpHandler(string merchantId, string merchantSerialNo, string privateKey, string json = "")

        {

            HttpClientHandler handler = new HttpClientHandler();

            handler.ClientCertificateOptions = ClientCertificateOption.Manual;

            handler.SslProtocols = SslProtocols.Tls12;

            try

            {

                string certPath = System.IO.Path.Combine(Environment.CurrentDirectory, @"Cert\apiclient_cert.p12");

                handler.ClientCertificates.Add(new X509Certificate2(certPath, "",

                    X509KeyStorageFlags.PersistKeySet | X509KeyStorageFlags.MachineKeySet));

            }

            catch (Exception e)

            {

                throw new Exception("ca err(证书错误)");

            }

            handler.SslProtocols = SslProtocols.Tls12 | SslProtocols.Tls11 | SslProtocols.Tls;

            handler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => true;

            InnerHandler = handler;

            this.merchantId = merchantId;

            this.serialNo = merchantSerialNo;

            this.privateKey = privateKey;

            this.json = json;

        }

        protected async override Task<HttpResponseMessage> SendAsync(

            HttpRequestMessage request,

            CancellationToken cancellationToken)

        {

            var auth = await BuildAuthAsync(request);

            string value = $"WECHATPAY2-SHA256-RSA2048 {auth}";

            request.Headers.Add("Authorization", value);

            request.Headers.Add("user-agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.143 Safari/537.36");

            MediaTypeWithQualityHeaderValue mediaTypeWithQualityHeader = new MediaTypeWithQualityHeaderValue("application/json");

            request.Headers.Accept.Add(mediaTypeWithQualityHeader);

            request.Headers.AcceptCharset.Add(new StringWithQualityHeaderValue("utf-8"));

            return await base.SendAsync(request, cancellationToken);

        }

        protected async Task<string> BuildAuthAsync(HttpRequestMessage request)

        {

            string method = request.Method.ToString();

            string body = "";

            if (method == "POST" || method == "PUT" || method == "PATCH")

            {

                if (!string.IsNullOrEmpty(json))

                    body = json;

                else

                {

                    var content = request.Content;

                    body = await content.ReadAsStringAsync();

                }

            }

            string uri = request.RequestUri.PathAndQuery;

            var timestamp = DateTimeOffset.Now.ToUnixTimeSeconds();

            string nonce = Guid.NewGuid().ToString("n");

            string message = $"{method}\n{uri}\n{timestamp}\n{nonce}\n{body}\n";

            string signature = Sign(message);

            return $"mchid=\"{merchantId}\",nonce_str=\"{nonce}\",timestamp=\"{timestamp}\",serial_no=\"{serialNo}\",signature=\"{signature}\"";

        }

        protected string Sign(string message)

        {

            byte[] keyData = Convert.FromBase64String(privateKey);

            using (CngKey cngKey = CngKey.Import(keyData, CngKeyBlobFormat.Pkcs8PrivateBlob))

            using (RSACng rsa = new RSACng(cngKey))

            {

                byte[] data = System.Text.Encoding.UTF8.GetBytes(message);

                return Convert.ToBase64String(rsa.SignData(data, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1));

            }

        }

    }

}

巴特西

微信支付v3版本NET 图片上传API

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