1.配置API接收
2.下載加密解密庫
地址：https://developer.work.weixin.qq.com/devtool/introduce?id=36388，也可以複製下面的程式碼
2.1 WXBizMsgCrypt.cs
該方法封裝了VerifyURL, DecryptMsg, EncryptMsg三個介面，分別用於開發者驗證回撥url，收到使用者回覆訊息的解密以及開發者回覆訊息的加密過程。
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 ： 簽名驗證錯誤 //-40002 : xml解析失敗 //-40003 : sha加密生成簽名失敗 //-40004 : AESKey 非法 //-40005 : corpid 校驗錯誤 //-40006 : AES 加密失敗 //-40007 ： AES 解密失敗 //-40008 ： 解密後得到的buffer非法 //-40009 : base64加密異常 //-40010 : base64解密異常 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 }; //建構函式 // @param sToken: 企業微信後臺，開發者設定的Token // @param sEncodingAESKey: 企業微信後臺，開發者設定的EncodingAESKey // @param sReceiveId: 不同場景含義不同，詳見文件說明 public WXBizMsgCrypt(string sToken, string sEncodingAESKey, string sReceiveId) { m_sToken = sToken; m_sReceiveId = sReceiveId; m_sEncodingAESKey = sEncodingAESKey; } //驗證URL // @param sMsgSignature: 簽名串，對應URL引數的msg_signature // @param sTimeStamp: 時間戳，對應URL引數的timestamp // @param sNonce: 隨機串，對應URL引數的nonce // @param sEchoStr: 隨機串，對應URL引數的echostr // @param sReplyEchoStr: 解密之後的echostr，當return返回0時有效 // @return：成功0，失敗返回對應的錯誤碼 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; } // 檢驗訊息的真實性，並且獲取解密後的明文 // @param sMsgSignature: 簽名串，對應URL引數的msg_signature // @param sTimeStamp: 時間戳，對應URL引數的timestamp // @param sNonce: 隨機串，對應URL引數的nonce // @param sPostData: 密文，對應POST請求的資料 // @param sMsg: 解密後的原文，當return返回0時有效 // @return: 成功0，失敗返回對應的錯誤碼 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; } //將企業號回覆使用者的訊息加密打包 // @param sReplyMsg: 企業號待回覆使用者的訊息，xml格式的字串 // @param sTimeStamp: 時間戳，可以自己生成，也可以用URL引數的timestamp // @param sNonce: 隨機串，可以自己生成，也可以用URL引數的nonce // @param sEncryptMsg: 加密後的可以直接回複使用者的密文，包括msg_signature, timestamp, nonce, encrypt的xml格式的字串, // 當return返回0時有效 // return：成功0，失敗返回對應的錯誤碼 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; } } }
2.2 Cryptography.cs
該檔案封裝了AES加解密過程
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(); //祕鑰的大小，以位為單位 aes.KeySize = 256; //支援的塊大小 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(); //祕鑰的大小，以位為單位 aes.KeySize = 256; //支援的塊大小 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 自己進行PKCS7補位，用系統自己帶的不行 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 註釋的也是一種方法，效果一樣 //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; // 計算需要填充的位數 int amount_to_pad = block_size - (text_length % block_size); if (amount_to_pad == 0) { amount_to_pad = block_size; } // 獲得補位所用的字元 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); } /** * 將數字轉化成ASCII碼對應的字元，用於對明文進行補碼 * * @param a 需要轉化的數字 * @return 轉化得到的字元 */ 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; } } }
3.編寫回撥API
3.1 支援Http Get請求驗證URL有效性
假設企業的接收訊息的URL設定為http://api.com/callback/interAspect
企業管理員在儲存回撥配置資訊時，企業微信會傳送一條驗證訊息到填寫的URL，請求內容如下：
請求方式：GET
請求地址：http://api.com/callback/interAspect?msg_signature=ASDFQWEXZCVAQFASDFASDFSS×tamp=13500001234&nonce=123412323&echostr=ENCRYPT_STR
引數說明：
| 引數 | 型別 | 說明 |
|---|---|---|
| msg_signature | String | 企業微信加密簽名，msg_signature計算結合了企業填寫的token、請求中的timestamp、nonce、加密的訊息體。簽名計算方法參考 訊息體簽名檢驗 |
| timestamp | Integer | 時間戳。與nonce結合使用，用於防止請求重放攻擊。 |
| nonce | String | 隨機數。與timestamp結合使用，用於防止請求重放攻擊。 |
| echostr | String | 加密的字串。需要解密得到訊息內容明文，解密後有random、msg_len、msg、receiveid四個欄位，其中msg即為訊息內容明文 |
[HttpGet, Route("callback/interAspect")] public ContentResult ReveiceMsg(string msg_signature,string timestamp,string nonce,string echostr) { //驗證 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支援Http Post請求接收業務資料
假設企業的接收訊息的URL設定為http://api.com/callback/interAspect。
當使用者觸發回撥行為時，企業微信會傳送回撥訊息到填寫的URL，請求內容如下：
請求方式：POST
請求地址 ：http://api.com/callback/interAspect?msg_signature=ASDFQWEXZCVAQFASDFASDFSS×tamp=13500001234&nonce=123412323
引數說明：
| 引數 | 型別 | 說明 |
|---|---|---|
| msg_signature | String | 企業微信加密簽名，msg_signature結合了企業填寫的token、請求中的timestamp、nonce引數、加密的訊息體 |
| timestamp | Integer | 時間戳。與nonce結合使用，用於防止請求重放攻擊。 |
| nonce | String | 隨機數。與timestamp結合使用，用於防止請求重放攻擊。 |
| ToUserName | String | 企業微信的CorpID，當為第三方應用回撥事件時，CorpID的內容為suiteid |
| AgentID | String | 接收的應用id，可在應用的設定頁面獲取。僅應用相關的回撥會帶該欄位。 |
| Encrypt | String | 訊息結構體加密後的字串 |
其中Encrypt為Xml格式，需要從請求體獲取。
[HttpPost, Route("callback/interAspect")] public ContentResult AcceptMessage(string msg_signature,string timestamp,string nonce) { //獲取Encrypt引數 string encrypt = ""; using (StreamReader sr = new StreamReader(Request.Body, Encoding.UTF8)) { encrypt = sr.ReadToEndAsync().Result; } //驗證 WXBizMsgCrypt wxcpt = new WXBizMsgCrypt(AppSetting.Configuration["Wx:CallBackToken"] , AppSetting.Configuration["Wx:EncodingAESKey"] , AppSetting.Configuration["Wx:corpid"]); string sMsg = ""; // 解析之後的明文 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表示解密之後的明文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; //這邊寫回撥業務邏輯 return Content("成功"); }
4.寫在最後
1.測試回撥模式地址,位置建立連線 => 測試回撥模式，用於測試Get介面是否具備解密能力，
連結https://open.work.weixin.qq.com/wwopen/devtool/interface/combine
2.openapi回撥地址請求不通過: https://www.cnblogs.com/zspwf/p/16381688.html
3. POST回撥不執行: 可能產生的原因有錯誤接收Encrypt引數，需注意Encrypt引數為Xml型別。Post無法除錯，需釋出到伺服器中，可通過輸出到系統日誌，獲取報錯原因。
4.域名必須為公網域名。
5.回撥配置官方文件：https://developer.work.weixin.qq.com/document/path/90930