1.配置API接收
2.下载加密解密库
地址：https://developer.work.weixin.qq.com/devtool/introduce?id=36388，也可以复制下面的代码
2.1 WXBizMsgCrypt.cs
该方法封装了VerifyURL, DecryptMsg, EncryptMsg三个接口，分别用于开发者验证回调url，收到用户回复消息的解密以及开发者回复消息的加密过程。
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Xml; using System.Collections; //using System.Web; using System.Security.Cryptography; //-40001 ： 签名验证错误 //-40002 : xml解析失败 //-40003 : sha加密生成签名失败 //-40004 : AESKey 非法 //-40005 : corpid 校验错误 //-40006 : AES 加密失败 //-40007 ： AES 解密失败 //-40008 ： 解密后得到的buffer非法 //-40009 : base64加密异常 //-40010 : base64解密异常 namespace Entity { public class WXBizMsgCrypt { string m_sToken; string m_sEncodingAESKey; string m_sReceiveId; enum WXBizMsgCryptErrorCode { WXBizMsgCrypt_OK = 0, WXBizMsgCrypt_ValidateSignature_Error = -40001, WXBizMsgCrypt_ParseXml_Error = -40002, WXBizMsgCrypt_ComputeSignature_Error = -40003, WXBizMsgCrypt_IllegalAesKey = -40004, WXBizMsgCrypt_ValidateCorpid_Error = -40005, WXBizMsgCrypt_EncryptAES_Error = -40006, WXBizMsgCrypt_DecryptAES_Error = -40007, WXBizMsgCrypt_IllegalBuffer = -40008, WXBizMsgCrypt_EncodeBase64_Error = -40009, WXBizMsgCrypt_DecodeBase64_Error = -40010 }; //构造函数 // @param sToken: 企业微信后台，开发者设置的Token // @param sEncodingAESKey: 企业微信后台，开发者设置的EncodingAESKey // @param sReceiveId: 不同场景含义不同，详见文档说明 public WXBizMsgCrypt(string sToken, string sEncodingAESKey, string sReceiveId) { m_sToken = sToken; m_sReceiveId = sReceiveId; m_sEncodingAESKey = sEncodingAESKey; } //验证URL // @param sMsgSignature: 签名串，对应URL参数的msg_signature // @param sTimeStamp: 时间戳，对应URL参数的timestamp // @param sNonce: 随机串，对应URL参数的nonce // @param sEchoStr: 随机串，对应URL参数的echostr // @param sReplyEchoStr: 解密之后的echostr，当return返回0时有效 // @return：成功0，失败返回对应的错误码 public int VerifyURL(string sMsgSignature, string sTimeStamp, string sNonce, string sEchoStr, ref string sReplyEchoStr) { int ret = 0; if (m_sEncodingAESKey.Length!=43) { return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_IllegalAesKey; } ret = VerifySignature(m_sToken, sTimeStamp, sNonce, sEchoStr, sMsgSignature); if (0 != ret) { return ret; } sReplyEchoStr = ""; string cpid = ""; try { sReplyEchoStr = Cryptography.AES_decrypt(sEchoStr, m_sEncodingAESKey, ref cpid); //m_sReceiveId); } catch (Exception) { sReplyEchoStr = ""; return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_DecryptAES_Error; } if (cpid != m_sReceiveId) { sReplyEchoStr = ""; return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_ValidateCorpid_Error; } return 0; } // 检验消息的真实性，并且获取解密后的明文 // @param sMsgSignature: 签名串，对应URL参数的msg_signature // @param sTimeStamp: 时间戳，对应URL参数的timestamp // @param sNonce: 随机串，对应URL参数的nonce // @param sPostData: 密文，对应POST请求的数据 // @param sMsg: 解密后的原文，当return返回0时有效 // @return: 成功0，失败返回对应的错误码 public int DecryptMsg(string sMsgSignature, string sTimeStamp, string sNonce, string sPostData, ref string sMsg) { if (m_sEncodingAESKey.Length!=43) { return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_IllegalAesKey; } XmlDocument doc = new XmlDocument(); XmlNode root; string sEncryptMsg; try { doc.LoadXml(sPostData); root = doc.FirstChild; sEncryptMsg = root["Encrypt"].InnerText; } catch (Exception) { return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_ParseXml_Error; } //verify signature int ret = 0; ret = VerifySignature(m_sToken, sTimeStamp, sNonce, sEncryptMsg, sMsgSignature); if (ret != 0) return ret; //decrypt string cpid = ""; try { sMsg = Cryptography.AES_decrypt(sEncryptMsg, m_sEncodingAESKey, ref cpid); } catch (FormatException) { sMsg = ""; return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_DecodeBase64_Error; } catch (Exception) { sMsg = ""; return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_DecryptAES_Error; } if (cpid != m_sReceiveId) return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_ValidateCorpid_Error; return 0; } //将企业号回复用户的消息加密打包 // @param sReplyMsg: 企业号待回复用户的消息，xml格式的字符串 // @param sTimeStamp: 时间戳，可以自己生成，也可以用URL参数的timestamp // @param sNonce: 随机串，可以自己生成，也可以用URL参数的nonce // @param sEncryptMsg: 加密后的可以直接回复用户的密文，包括msg_signature, timestamp, nonce, encrypt的xml格式的字符串, // 当return返回0时有效 // return：成功0，失败返回对应的错误码 public int EncryptMsg(string sReplyMsg, string sTimeStamp, string sNonce, ref string sEncryptMsg) { if (m_sEncodingAESKey.Length!=43) { return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_IllegalAesKey; } string raw = ""; try { raw = Cryptography.AES_encrypt(sReplyMsg, m_sEncodingAESKey, m_sReceiveId); } catch (Exception) { return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_EncryptAES_Error; } string MsgSigature = ""; int ret = 0; ret = GenarateSinature(m_sToken, sTimeStamp, sNonce, raw, ref MsgSigature); if (0 != ret) return ret; sEncryptMsg = ""; string EncryptLabelHead = "<Encrypt><![CDATA["; string EncryptLabelTail = "]]></Encrypt>"; string MsgSigLabelHead = "<MsgSignature><![CDATA["; string MsgSigLabelTail = "]]></MsgSignature>"; string TimeStampLabelHead = "<TimeStamp><![CDATA["; string TimeStampLabelTail = "]]></TimeStamp>"; string NonceLabelHead = "<Nonce><![CDATA["; string NonceLabelTail = "]]></Nonce>"; sEncryptMsg = sEncryptMsg + "<xml>" + EncryptLabelHead + raw + EncryptLabelTail; sEncryptMsg = sEncryptMsg + MsgSigLabelHead + MsgSigature + MsgSigLabelTail; sEncryptMsg = sEncryptMsg + TimeStampLabelHead + sTimeStamp + TimeStampLabelTail; sEncryptMsg = sEncryptMsg + NonceLabelHead + sNonce + NonceLabelTail; sEncryptMsg += "</xml>"; return 0; } public class DictionarySort : System.Collections.IComparer { public int Compare(object oLeft, object oRight) { string sLeft = oLeft as string; string sRight = oRight as string; int iLeftLength = sLeft.Length; int iRightLength = sRight.Length; int index = 0; while (index < iLeftLength && index < iRightLength) { if (sLeft[index] < sRight[index]) return -1; else if (sLeft[index] > sRight[index]) return 1; else index++; } return iLeftLength - iRightLength; } } //Verify Signature private static int VerifySignature(string sToken, string sTimeStamp, string sNonce, string sMsgEncrypt, string sSigture) { string hash = ""; int ret = 0; ret = GenarateSinature(sToken, sTimeStamp, sNonce, sMsgEncrypt, ref hash); if (ret != 0) return ret; if (hash == sSigture) return 0; else { return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_ValidateSignature_Error; } } public static int GenarateSinature(string sToken, string sTimeStamp, string sNonce, string sMsgEncrypt ,ref string sMsgSignature) { ArrayList AL = new ArrayList(); AL.Add(sToken); AL.Add(sTimeStamp); AL.Add(sNonce); AL.Add(sMsgEncrypt); AL.Sort(new DictionarySort()); string raw = ""; for (int i = 0; i < AL.Count; ++i) { raw += AL[i]; } SHA1 sha; ASCIIEncoding enc; string hash = ""; try { sha = new SHA1CryptoServiceProvider(); enc = new ASCIIEncoding(); byte[] dataToHash = enc.GetBytes(raw); byte[] dataHashed = sha.ComputeHash(dataToHash); hash = BitConverter.ToString(dataHashed).Replace("-", ""); hash = hash.ToLower(); } catch (Exception) { return (int)WXBizMsgCryptErrorCode.WXBizMsgCrypt_ComputeSignature_Error; } sMsgSignature = hash; return 0; } } }
WXBizMsgCrypt.cs
2.2 Cryptography.cs
该文件封装了AES加解密过程
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Security.Cryptography; using System.IO; using System.Net; namespace Entity { public class Cryptography { public static UInt32 HostToNetworkOrder(UInt32 inval) { UInt32 outval = 0; for (int i = 0; i < 4; i++) outval = (outval << 8) + ((inval >> (i * 8)) & 255); return outval; } public static Int32 HostToNetworkOrder(Int32 inval) { Int32 outval = 0; for (int i = 0; i < 4; i++) outval = (outval << 8) + ((inval >> (i * 8)) & 255); return outval; } /// <summary> /// 解密方法 /// </summary> /// <param name="Input">密文</param> /// <param name="EncodingAESKey"></param> /// <returns></returns> /// public static string AES_decrypt(String Input, string EncodingAESKey, ref string corpid) { byte[] Key; Key = Convert.FromBase64String(EncodingAESKey + "="); byte[] Iv = new byte[16]; Array.Copy(Key, Iv, 16); byte[] btmpMsg = AES_decrypt(Input, Iv, Key); int len = BitConverter.ToInt32(btmpMsg, 16); len = IPAddress.NetworkToHostOrder(len); byte[] bMsg = new byte[len]; byte[] bCorpid = new byte[btmpMsg.Length - 20 - len]; Array.Copy(btmpMsg, 20, bMsg, 0, len); Array.Copy(btmpMsg, 20+len , bCorpid, 0, btmpMsg.Length - 20 - len); string oriMsg = Encoding.UTF8.GetString(bMsg); corpid = Encoding.UTF8.GetString(bCorpid); return oriMsg; } public static String AES_encrypt(String Input, string EncodingAESKey, string corpid) { byte[] Key; Key = Convert.FromBase64String(EncodingAESKey + "="); byte[] Iv = new byte[16]; Array.Copy(Key, Iv, 16); string Randcode = CreateRandCode(16); byte[] bRand = Encoding.UTF8.GetBytes(Randcode); byte[] bCorpid = Encoding.UTF8.GetBytes(corpid); byte[] btmpMsg = Encoding.UTF8.GetBytes(Input); byte[] bMsgLen = BitConverter.GetBytes(HostToNetworkOrder(btmpMsg.Length)); byte[] bMsg = new byte[bRand.Length + bMsgLen.Length + bCorpid.Length + btmpMsg.Length]; Array.Copy(bRand, bMsg, bRand.Length); Array.Copy(bMsgLen, 0, bMsg, bRand.Length, bMsgLen.Length); Array.Copy(btmpMsg, 0, bMsg, bRand.Length + bMsgLen.Length, btmpMsg.Length); Array.Copy(bCorpid, 0, bMsg, bRand.Length + bMsgLen.Length + btmpMsg.Length, bCorpid.Length); return AES_encrypt(bMsg, Iv, Key); } private static string CreateRandCode(int codeLen) { string codeSerial = "2,3,4,5,6,7,a,c,d,e,f,h,i,j,k,m,n,p,r,s,t,A,C,D,E,F,G,H,J,K,M,N,P,Q,R,S,U,V,W,X,Y,Z"; if (codeLen == 0) { codeLen = 16; } string[] arr = codeSerial.Split(','); string code = ""; int randValue = -1; Random rand = new Random(unchecked((int)DateTime.Now.Ticks)); for (int i = 0; i < codeLen; i++) { randValue = rand.Next(0, arr.Length - 1); code += arr[randValue]; } return code; } private static String AES_encrypt(String Input, byte[] Iv, byte[] Key) { var aes = new RijndaelManaged(); //秘钥的大小，以位为单位 aes.KeySize = 256; //支持的块大小 aes.BlockSize = 128; //填充模式 aes.Padding = PaddingMode.PKCS7; aes.Mode = CipherMode.CBC; aes.Key = Key; aes.IV = Iv; var encrypt = aes.CreateEncryptor(aes.Key, aes.IV); byte[] xBuff = null; using (var ms = new MemoryStream()) { using (var cs = new CryptoStream(ms, encrypt, CryptoStreamMode.Write)) { byte[] xXml = Encoding.UTF8.GetBytes(Input); cs.Write(xXml, 0, xXml.Length); } xBuff = ms.ToArray(); } String Output = Convert.ToBase64String(xBuff); return Output; } private static String AES_encrypt(byte[] Input, byte[] Iv, byte[] Key) { var aes = new RijndaelManaged(); //秘钥的大小，以位为单位 aes.KeySize = 256; //支持的块大小 aes.BlockSize = 128; //填充模式 //aes.Padding = PaddingMode.PKCS7; aes.Padding = PaddingMode.None; aes.Mode = CipherMode.CBC; aes.Key = Key; aes.IV = Iv; var encrypt = aes.CreateEncryptor(aes.Key, aes.IV); byte[] xBuff = null; #region 自己进行PKCS7补位，用系统自己带的不行 byte[] msg = new byte[Input.Length + 32 - Input.Length % 32]; Array.Copy(Input, msg, Input.Length); byte[] pad = KCS7Encoder(Input.Length); Array.Copy(pad, 0, msg, Input.Length, pad.Length); #endregion #region 注释的也是一种方法，效果一样 //ICryptoTransform transform = aes.CreateEncryptor(); //byte[] xBuff = transform.TransformFinalBlock(msg, 0, msg.Length); #endregion using (var ms = new MemoryStream()) { using (var cs = new CryptoStream(ms, encrypt, CryptoStreamMode.Write)) { cs.Write(msg, 0, msg.Length); } xBuff = ms.ToArray(); } String Output = Convert.ToBase64String(xBuff); return Output; } private static byte[] KCS7Encoder(int text_length) { int block_size = 32; // 计算需要填充的位数 int amount_to_pad = block_size - (text_length % block_size); if (amount_to_pad == 0) { amount_to_pad = block_size; } // 获得补位所用的字符 char pad_chr = chr(amount_to_pad); string tmp = ""; for (int index = 0; index < amount_to_pad; index++) { tmp += pad_chr; } return Encoding.UTF8.GetBytes(tmp); } /** * 将数字转化成ASCII码对应的字符，用于对明文进行补码 * * @param a 需要转化的数字 * @return 转化得到的字符 */ static char chr(int a) { byte target = (byte)(a & 0xFF); return (char)target; } private static byte[] AES_decrypt(String Input, byte[] Iv, byte[] Key) { RijndaelManaged aes = new RijndaelManaged(); aes.KeySize = 256; aes.BlockSize = 128; aes.Mode = CipherMode.CBC; aes.Padding = PaddingMode.None; aes.Key = Key; aes.IV = Iv; var decrypt = aes.CreateDecryptor(aes.Key, aes.IV); byte[] xBuff = null; using (var ms = new MemoryStream()) { using (var cs = new CryptoStream(ms, decrypt, CryptoStreamMode.Write)) { byte[] xXml = Convert.FromBase64String(Input); byte[] msg = new byte[xXml.Length + 32 - xXml.Length % 32]; Array.Copy(xXml, msg, xXml.Length); cs.Write(xXml, 0, xXml.Length); } xBuff = decode2(ms.ToArray()); } return xBuff; } private static byte[] decode2(byte[] decrypted) { int pad = (int)decrypted[decrypted.Length - 1]; if (pad < 1 || pad > 32) { pad = 0; } byte[] res = new byte[decrypted.Length - pad]; Array.Copy(decrypted, 0, res, 0, decrypted.Length - pad); return res; } } }
Cryptography.cs
3.编写回调API
3.1 支持Http Get请求验证URL有效性
假设企业的接收消息的URL设置为http://api.com/callback/interAspect
企业管理员在保存回调配置信息时，企业微信会发送一条验证消息到填写的URL，请求内容如下：
请求方式：GET
请求地址：http://api.com/callback/interAspect?msg_signature=ASDFQWEXZCVAQFASDFASDFSS×tamp=13500001234&nonce=123412323&echostr=ENCRYPT_STR
参数说明：
| 参数 | 类型 | 说明 |
|---|---|---|
| msg_signature | String | 企业微信加密签名，msg_signature计算结合了企业填写的token、请求中的timestamp、nonce、加密的消息体。签名计算方法参考 消息体签名检验 |
| timestamp | Integer | 时间戳。与nonce结合使用，用于防止请求重放攻击。 |
| nonce | String | 随机数。与timestamp结合使用，用于防止请求重放攻击。 |
| echostr | String | 加密的字符串。需要解密得到消息内容明文，解密后有random、msg_len、msg、receiveid四个字段，其中msg即为消息内容明文 |
[HttpGet, Route("callback/interAspect")] public ContentResult ReveiceMsg(string msg_signature,string timestamp,string nonce,string echostr) { //验证 WXBizMsgCrypt wxcpt = new WXBizMsgCrypt(AppSetting.Configuration["Wx:CallBackToken"] , AppSetting.Configuration["Wx:EncodingAESKey"] , AppSetting.Configuration["Wx:corpid"]); int ret = 0; string sEchoStr = ""; ret = wxcpt.VerifyURL(msg_signature, timestamp, nonce, echostr, ref sEchoStr); if (ret != 0) { return Content(null); } return Content(sEchoStr); }
3.2支持Http Post请求接收业务数据
假设企业的接收消息的URL设置为http://api.com/callback/interAspect。
当用户触发回调行为时，企业微信会发送回调消息到填写的URL，请求内容如下：
请求方式：POST
请求地址 ：http://api.com/callback/interAspect?msg_signature=ASDFQWEXZCVAQFASDFASDFSS×tamp=13500001234&nonce=123412323
参数说明：
| 参数 | 类型 | 说明 |
|---|---|---|
| msg_signature | String | 企业微信加密签名，msg_signature结合了企业填写的token、请求中的timestamp、nonce参数、加密的消息体 |
| timestamp | Integer | 时间戳。与nonce结合使用，用于防止请求重放攻击。 |
| nonce | String | 随机数。与timestamp结合使用，用于防止请求重放攻击。 |
| ToUserName | String | 企业微信的CorpID，当为第三方应用回调事件时，CorpID的内容为suiteid |
| AgentID | String | 接收的应用id，可在应用的设置页面获取。仅应用相关的回调会带该字段。 |
| Encrypt | String | 消息结构体加密后的字符串 |
其中Encrypt为Xml格式，需要从请求体获取。
[HttpPost, Route("callback/interAspect")] public ContentResult AcceptMessage(string msg_signature,string timestamp,string nonce) { //获取Encrypt参数 string encrypt = ""; using (StreamReader sr = new StreamReader(Request.Body, Encoding.UTF8)) { encrypt = sr.ReadToEndAsync().Result; } //验证 WXBizMsgCrypt wxcpt = new WXBizMsgCrypt(AppSetting.Configuration["Wx:CallBackToken"] , AppSetting.Configuration["Wx:EncodingAESKey"] , AppSetting.Configuration["Wx:corpid"]); string sMsg = ""; // 解析之后的明文 int ret = wxcpt.DecryptMsg(msg_signature, timestamp, nonce, encrypt, ref sMsg); if (ret != 0) { throw new Exception(); } // ret==0表示解密成功，sMsg表示解密之后的明文xml串 XmlDocument doc = new XmlDocument(); doc.LoadXml(sMsg); XmlNode root = doc.FirstChild; string userName = root["FromUserName"].InnerText; string eventKey = root["EventKey"].InnerText; string responseCode = root["ResponseCode"].InnerText; //这边写回调业务逻辑 return Content("成功"); }
4.写在最后
1.测试回调模式地址,位置建立连接 => 测试回调模式，用于测试Get接口是否具备解密能力，
链接https://open.work.weixin.qq.com/wwopen/devtool/interface/combine
2.openapi回调地址请求不通过: https://www.cnblogs.com/zspwf/p/16381688.html
3. POST回调不执行: 可能产生的原因有错误接收Encrypt参数，需注意Encrypt参数为Xml类型。Post无法调试，需发布到服务器中，可通过输出到系统日志，获取报错原因。
4.域名必须为公网域名。
5.回调配置官方文档：https://developer.work.weixin.qq.com/document/path/90930
