feat(openai): 新增反序列化回调通知事件得扩展方法

src/SKIT.FlurlHttpClient.Wechat.OpenAI/Exceptions/WechatOpenAIEventSerializationException.cs

@@ -0,0 +1,24 @@
+using System;
+
+namespace SKIT.FlurlHttpClient.Wechat.OpenAI.Exceptions
+{
+    public class WechatOpenAIEventSerializationException : WechatOpenAIException
+    {
+        /// <inheritdoc/>
+        internal WechatOpenAIEventSerializationException()
+        {
+        }
+
+        /// <inheritdoc/>
+        internal WechatOpenAIEventSerializationException(string message) 
+            : base(message)
+        {
+        }
+
+        /// <inheritdoc/>
+        internal WechatOpenAIEventSerializationException(string message, Exception innerException) 
+            : base(message, innerException)
+        {
+        }
+    }
+}

src/SKIT.FlurlHttpClient.Wechat.OpenAI/Extensions/WechatOpenAIClientEventExtensions.cs

@@ -0,0 +1,143 @@
+using System;
+using System.IO;
+using System.Text;
+using System.Text.RegularExpressions;
+using System.Xml.Linq;
+using System.Xml.Serialization;
+
+namespace SKIT.FlurlHttpClient.Wechat.OpenAI
+{
+    /// <summary>
+    /// 为 <see cref="WechatOpenAIClient"/> 提供回调通知事件的扩展方法。
+    /// </summary>
+    public static class WechatOpenAIClientEventExtensions
+    {
+        private class EncryptedWechatOpenAIEvent
+        {
+            [Newtonsoft.Json.JsonProperty("Encrypt")]
+            [System.Text.Json.Serialization.JsonPropertyName("Encrypt")]
+            public string EncryptedData { get; set; } = default!;
+
+            [Newtonsoft.Json.JsonProperty("TimeStamp")]
+            [System.Text.Json.Serialization.JsonPropertyName("TimeStamp")]
+            [System.Text.Json.Serialization.JsonConverter(typeof(System.Text.Json.Converters.NumericalStringConverter))]
+            public string Timestamp { get; set; } = default!;
+
+            [Newtonsoft.Json.JsonProperty("Nonce")]
+            [System.Text.Json.Serialization.JsonPropertyName("Nonce")]
+            public string Nonce { get; set; } = default!;
+
+            [Newtonsoft.Json.JsonProperty("MsgSignature")]
+            [System.Text.Json.Serialization.JsonPropertyName("MsgSignature")]
+            public string Signature { get; set; } = default!;
+        }
+
+        private static TEvent InnerDeserializeEventFromXml<TEvent>(this WechatOpenAIClient client, string callbackXml)
+            where TEvent : WechatOpenAIEvent
+        {
+            if (client == null) throw new ArgumentNullException(nameof(client));
+            if (string.IsNullOrEmpty(callbackXml)) throw new ArgumentNullException(callbackXml);
+
+            try
+            {
+                if (!Utilities.WxBizMsgCryptor.TryParseXml(callbackXml, out string? encryptedXml))
+                    throw new Exceptions.WechatOpenAIEventSerializationException("Encrypt event failed, because of empty encrypted data.");
+
+                callbackXml = Utilities.WxBizMsgCryptor.AESDecrypt(cipherText: encryptedXml!, encodingAESKey: client.Credentials.PushEncodingAESKey!, out _);
+
+                using var reader = new StringReader(callbackXml);
+
+                XmlSerializer xmlSerializer = new XmlSerializer(typeof(TEvent), new XmlRootAttribute("xml"));
+                return (TEvent)xmlSerializer.Deserialize(reader)!;
+            }
+            catch (WechatOpenAIException)
+            {
+                throw;
+            }
+            catch (Exception ex)
+            {
+                throw new Exceptions.WechatOpenAIEventSerializationException("Deserialize event failed. Please see the `InnerException` for more details.", ex);
+            }
+        }
+
+        /// <summary>
+        /// <para>从 XML 反序列化得到 <see cref="WechatOpenAIEvent"/> 对象。</para>
+        /// </summary>
+        /// <typeparam name="TEvent"></typeparam>
+        /// <param name="client"></param>
+        /// <param name="callbackXml"></param>
+        /// <returns></returns>
+        public static TEvent DeserializeEventFromXml<TEvent>(this WechatOpenAIClient client, string callbackXml)
+            where TEvent : WechatOpenAIEvent, WechatOpenAIEvent.Serialization.IXmlSerializable, new()
+        {
+            return InnerDeserializeEventFromXml<TEvent>(client, callbackXml);
+        }
+
+        /// <summary>
+        /// <para>从 XML 反序列化得到 <see cref="WechatOpenAIEvent"/> 对象。</para>
+        /// </summary>
+        /// <param name="client"></param>
+        /// <param name="callbackXml"></param>
+        /// <returns></returns>
+        public static WechatOpenAIEvent DeserializeEventFromXml(this WechatOpenAIClient client, string callbackXml)
+        {
+            return InnerDeserializeEventFromXml<WechatOpenAIEvent>(client, callbackXml);
+        }
+
+        /// <summary>
+        /// 将 <see cref="WechatOpenAIEvent"/> 对象序列化成 XML。
+        /// </summary>
+        /// <typeparam name="TEvent"></typeparam>
+        /// <param name="client"></param>
+        /// <param name="callbackModel"></param>
+        /// <returns></returns>
+        public static string SerializeEventToXml<TEvent>(this WechatOpenAIClient client, TEvent callbackModel)
+            where TEvent : WechatOpenAIEvent, WechatOpenAIEvent.Serialization.IXmlSerializable, new()
+        {
+            string xml;
+
+            try
+            {
+                using var stream = new MemoryStream();
+                using var writer = new System.Xml.XmlTextWriter(stream, Encoding.UTF8);
+                writer.Formatting = System.Xml.Formatting.None;
+
+                XmlSerializer xmlSerializer = new XmlSerializer(typeof(TEvent), new XmlRootAttribute("xml"));
+                XmlSerializerNamespaces xmlNamespace = new XmlSerializerNamespaces();
+                xmlNamespace.Add(string.Empty, string.Empty);
+                xmlSerializer.Serialize(writer, callbackModel, xmlNamespace);
+                writer.Flush();
+                xml = Encoding.UTF8.GetString(stream.ToArray());
+                xml = Regex.Replace(xml, "\\s+<\\w+ (xsi|d2p1):nil=\"true\"[^>]*/>", string.Empty, RegexOptions.IgnoreCase);
+                xml = Regex.Replace(xml, "<\\?xml[^>]*\\?>", string.Empty, RegexOptions.IgnoreCase);
+            }
+            catch (Exception ex)
+            {
+                throw new Exceptions.WechatOpenAIEventSerializationException("Serialize event failed. Please see the `InnerException` for more details.", ex);
+            }
+
+
+            if (string.IsNullOrEmpty(client.Credentials.PushEncodingAESKey))
+                throw new Exceptions.WechatOpenAIEventSerializationException("Encrypt event failed, because there is no encoding AES key.");
+            if (string.IsNullOrEmpty(client.Credentials.PushToken))
+                throw new Exceptions.WechatOpenAIEventSerializationException("Encrypt event failed, because there is no token.");
+
+            try
+            {
+                string cipher = Utilities.WxBizMsgCryptor.AESEncrypt(
+                    plainText: xml,
+                    encodingAESKey: client.Credentials.PushEncodingAESKey!,
+                    appId: client.Credentials.AppId!
+                );
+
+                xml = Utilities.WxBizMsgCryptor.WrapXml(sToken: client.Credentials.PushToken!, sMsgEncrypt: cipher);
+            }
+            catch (Exception ex)
+            {
+                throw new Exceptions.WechatOpenAIEventSerializationException("Encrypt event failed. Please see the `InnerException` for more details.", ex);
+            }
+
+            return xml;
+        }
+    }
+}

src/SKIT.FlurlHttpClient.Wechat.OpenAI/Settings/Credentials.cs

@@ -11,12 +11,27 @@ namespace SKIT.FlurlHttpClient.Wechat.OpenAI.Settings
         /// <summary>
         /// 初始化客户端时 <see cref="WechatOpenAIClientOptions.ClientId"/> 的副本。
         /// </summary>
-        public string ClientId { get; }
+        public string? ClientId { get; }
 
         /// <summary>
         /// 初始化客户端时 <see cref="WechatOpenAIClientOptions.ClientKey"/> 的副本。
         /// </summary>
-        public string ClientKey { get; }
+        public string? ClientKey { get; }
+
+        /// <summary>
+        /// 初始化客户端时 <see cref="WechatOpenAIClientOptions.AppId"/> 的副本。
+        /// </summary>
+        public string? AppId { get; }
+
+        /// <summary>
+        /// 初始化客户端时 <see cref="WechatOpenAIClientOptions.PushToken"/> 的副本。
+        /// </summary>
+        public string? PushToken { get; }
+
+        /// <summary>
+        /// 初始化客户端时 <see cref="WechatOpenAIClientOptions.PushEncodingAESKey"/> 的副本。
+        /// </summary>
+        public string? PushEncodingAESKey { get; }
 
         internal Credentials(WechatOpenAIClientOptions options)
         {
@@ -24,6 +39,9 @@ namespace SKIT.FlurlHttpClient.Wechat.OpenAI.Settings
 
             ClientId = options.ClientId;
             ClientKey = options.ClientKey;
+            AppId = options.AppId;
+            PushToken = options.PushToken;
+            PushEncodingAESKey = options.PushEncodingAESKey;
         }
     }
 }

src/SKIT.FlurlHttpClient.Wechat.OpenAI/Utilities/WxBizMsgCryptor.cs

@@ -0,0 +1,332 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Net;
+using System.Security;
+using System.Security.Cryptography;
+using System.Text;
+using System.Xml;
+
+namespace SKIT.FlurlHttpClient.Wechat.OpenAI.Utilities
+{
+    public static class WxBizMsgCryptor
+    {
+        private const int AES_KEY_SIZE = 256;
+        private const int AES_BLOCK_SIZE = 128;
+
+        private static char ConvertToChar(int i)
+        {
+            byte ret = (byte)(i & 0xFF);
+            return (char)ret;
+        }
+
+        private static byte[] KCS7Encoder(int len)
+        {
+            if (len <= 0) throw new ArgumentOutOfRangeException(nameof(len));
+
+            const int BLOCK_SIZE = 32;
+
+            int paddingLength = BLOCK_SIZE - (len % BLOCK_SIZE);
+            if (paddingLength == 0)
+            {
+                paddingLength = BLOCK_SIZE;
+            }
+
+            char paddingChar = ConvertToChar(paddingLength);
+            string tmp = string.Empty;
+            for (int index = 0; index < paddingLength; index++)
+            {
+                tmp += paddingChar;
+            }
+
+            return Encoding.UTF8.GetBytes(tmp);
+        }
+
+        private static string CreateRandCode(int len)
+        {
+            if (len <= 0) throw new ArgumentOutOfRangeException(nameof(len));
+
+            Random random = new Random(unchecked((int)DateTime.Now.Ticks));
+            string[] source = "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".Split(',');
+            string result = string.Empty;
+            for (int i = 0; i < len; i++)
+            {
+                int randval = random.Next(0, source.Length - 1);
+                result += source[randval];
+            }
+
+            return result;
+        }
+
+        private static byte[] Decode2(byte[] decryptedBytes)
+        {
+            if (decryptedBytes == null) throw new ArgumentNullException(nameof(decryptedBytes));
+
+            int pad = (int)decryptedBytes[decryptedBytes.Length - 1];
+            if (pad < 1 || pad > 32)
+            {
+                pad = 0;
+            }
+
+            byte[] res = new byte[decryptedBytes.Length - pad];
+            Array.Copy(decryptedBytes, 0, res, 0, decryptedBytes.Length - pad);
+            return res;
+        }
+
+        private static byte[] AESDecrypt(byte[] keyBytes, byte[] ivBytes, byte[] ciperBytes)
+        {
+            if (keyBytes == null) throw new ArgumentNullException(nameof(keyBytes));
+            if (ivBytes == null) throw new ArgumentNullException(nameof(ivBytes));
+            if (ciperBytes == null) throw new ArgumentNullException(nameof(ciperBytes));
+
+            using RijndaelManaged aes = new RijndaelManaged();
+            aes.KeySize = 256;
+            aes.BlockSize = 128;
+            aes.Mode = CipherMode.CBC;
+            //aes.Padding = PaddingMode.PKCS7;
+            aes.Padding = PaddingMode.None;
+            aes.Key = keyBytes;
+            aes.IV = ivBytes;
+
+            using (var decryptor = aes.CreateDecryptor(aes.Key, aes.IV))
+            using (var ms = new MemoryStream())
+            using (var cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Write))
+            {
+                byte[] bMsg = new byte[ciperBytes.Length + 32 - ciperBytes.Length % 32];
+                Array.Copy(ciperBytes, bMsg, ciperBytes.Length);
+                cs.Write(ciperBytes, 0, ciperBytes.Length);
+
+                byte[] plainBytes = Decode2(ms.ToArray());
+                return plainBytes;
+            }
+        }
+
+        private static string AESEncrypt(byte[] keyBytes, byte[] ivBytes, byte[] plainBytes)
+        {
+            if (keyBytes == null) throw new ArgumentNullException(nameof(keyBytes));
+            if (ivBytes == null) throw new ArgumentNullException(nameof(ivBytes));
+            if (plainBytes == null) throw new ArgumentNullException(nameof(plainBytes));
+
+            using var aes = new RijndaelManaged();
+            aes.KeySize = AES_KEY_SIZE;
+            aes.BlockSize = AES_BLOCK_SIZE;
+            //aes.Padding = PaddingMode.PKCS7;
+            aes.Padding = PaddingMode.None;
+            aes.Mode = CipherMode.CBC;
+            aes.Key = keyBytes;
+            aes.IV = ivBytes;
+
+            byte[] msgBytes = new byte[plainBytes.Length + 32 - plainBytes.Length % 32];
+            Array.Copy(plainBytes, msgBytes, plainBytes.Length);
+            byte[] padBytes = KCS7Encoder(plainBytes.Length);
+            Array.Copy(padBytes, 0, msgBytes, plainBytes.Length, padBytes.Length);
+
+            using (var encryptor = aes.CreateEncryptor(aes.Key, aes.IV))
+            using (var ms = new MemoryStream())
+            using (var cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
+            {
+                cs.Write(msgBytes, 0, msgBytes.Length);
+                byte[] cipherBytes = ms.ToArray();
+                return Convert.ToBase64String(cipherBytes);
+            }
+        }
+
+        /// <summary>
+        /// AES 解密微信回调加密数据。
+        /// </summary>
+        /// <param name="cipherText">微信推送来的加密文本内容（即 `Encrypt` 字段的值）。</param>
+        /// <param name="encodingAESKey">微信后台设置的 EncodingAESKey。</param>
+        /// <param name="appId">微信 AppId。</param>
+        /// <returns>解密后的文本内容。</returns>
+        public static string AESDecrypt(string cipherText, string encodingAESKey, out string appId)
+        {
+            if (cipherText == null) throw new ArgumentNullException(nameof(cipherText));
+            if (encodingAESKey == null) throw new ArgumentNullException(nameof(encodingAESKey));
+
+            byte[] cipherBytes = Convert.FromBase64String(cipherText);
+            byte[] keyBytes = Convert.FromBase64String(encodingAESKey + "=");
+            byte[] ivBytes = new byte[16];
+            Array.Copy(keyBytes, ivBytes, 16);
+            byte[] btmpMsg = AESDecrypt(ciperBytes: cipherBytes, ivBytes: ivBytes, keyBytes: keyBytes);
+
+            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);
+
+            appId = Encoding.UTF8.GetString(bCorpId);
+            return Encoding.UTF8.GetString(bMsg);
+        }
+
+        /// <summary>
+        /// AES 加密微信回调敏感数据。
+        /// </summary>
+        /// <param name="plainText">返回给微信的原始文本内容。</param>
+        /// <param name="encodingAESKey">微信后台设置的 EncodingAESKey。</param>
+        /// <param name="appId">微信 AppId。</param>
+        /// <returns>加密后的文本内容。</returns>
+        public static string AESEncrypt(string plainText, string encodingAESKey, string appId)
+        {
+            if (plainText == null) throw new ArgumentNullException(nameof(plainText));
+            if (encodingAESKey == null) throw new ArgumentNullException(nameof(encodingAESKey));
+            if (appId == null) throw new ArgumentNullException(nameof(appId));
+
+            byte[] keyBytes = Convert.FromBase64String(encodingAESKey + "=");
+            byte[] ivBytes = new byte[16];
+            Array.Copy(keyBytes, ivBytes, 16);
+
+            string randCode = CreateRandCode(16);
+            byte[] bRand = Encoding.UTF8.GetBytes(randCode);
+            byte[] bCorpId = Encoding.UTF8.GetBytes(appId);
+            byte[] bMsgTmp = Encoding.UTF8.GetBytes(plainText);
+            byte[] bMsgLen = BitConverter.GetBytes(IPAddress.HostToNetworkOrder(bMsgTmp.Length));
+            byte[] bMsg = new byte[bRand.Length + bMsgLen.Length + bCorpId.Length + bMsgTmp.Length];
+
+            Array.Copy(bRand, bMsg, bRand.Length);
+            Array.Copy(bMsgLen, 0, bMsg, bRand.Length, bMsgLen.Length);
+            Array.Copy(bMsgTmp, 0, bMsg, bRand.Length + bMsgLen.Length, bMsgTmp.Length);
+            Array.Copy(bCorpId, 0, bMsg, bRand.Length + bMsgLen.Length + bMsgTmp.Length, bCorpId.Length);
+
+            return AESEncrypt(keyBytes: keyBytes, ivBytes: ivBytes, plainBytes: bMsg);
+        }
+
+        /// <summary>
+        /// 验证微信回调签名。
+        /// </summary>
+        /// <param name="sToken">微信后台设置的 Token。</param>
+        /// <param name="sTimestamp">微信推送来的时间戳字符串。</param>
+        /// <param name="sNonce">微信推送来的随机字符串。</param>
+        /// <param name="sMsgEncrypt">微信推送来的加密文本内容（即 `Encrypt` 字段的值）。</param>
+        /// <param name="sMsgSign">待验证的签名。</param>
+        /// <returns>验证结果。</returns>
+        public static bool VerifySignature(string sToken, string sTimestamp, string sNonce, string sMsgEncrypt, string sMsgSign)
+        {
+            if (sToken == null) throw new ArgumentNullException(nameof(sToken));
+            if (sTimestamp == null) throw new ArgumentNullException(nameof(sTimestamp));
+            if (sNonce == null) throw new ArgumentNullException(nameof(sNonce));
+            if (sMsgEncrypt == null) throw new ArgumentNullException(nameof(sMsgEncrypt));
+            if (sMsgSign == null) throw new ArgumentNullException(nameof(sMsgSign));
+
+            string expectedSign = GenerateSignature(sToken, sTimestamp, sNonce, sMsgEncrypt);
+            return string.Equals(expectedSign, sMsgSign, StringComparison.OrdinalIgnoreCase);
+        }
+
+        /// <summary>
+        /// 生成微信回调签名。
+        /// </summary>
+        /// <param name="sToken">微信后台设置的 Token。</param>
+        /// <param name="sTimestamp">返回给微信的时间戳字符串。</param>
+        /// <param name="sNonce">返回给微信的随机字符串。</param>
+        /// <param name="sMsgEncrypt">返回给微信的加密文本内容。</param>
+        /// <returns>签名。</returns>
+        public static string GenerateSignature(string sToken, string sTimestamp, string sNonce, string sMsgEncrypt)
+        {
+            if (sToken == null) throw new ArgumentNullException(nameof(sToken));
+            if (sTimestamp == null) throw new ArgumentNullException(nameof(sTimestamp));
+            if (sNonce == null) throw new ArgumentNullException(nameof(sNonce));
+            if (sMsgEncrypt == null) throw new ArgumentNullException(nameof(sMsgEncrypt));
+
+            ISet<string> set = new SortedSet<string>(StringComparer.Ordinal);
+            set.Add(sToken);
+            set.Add(sTimestamp);
+            set.Add(sNonce);
+            set.Add(sMsgEncrypt);
+
+            string rawText = string.Join(string.Empty, set.ToArray());
+            string signText = Security.SHA1Utility.Hash(rawText);
+            return signText.ToLower();
+        }
+
+        /// <summary>
+        /// 尝试解析微信推送过来的 XML 数据（仅适用于兼容模式或安全模式）。
+        /// </summary>
+        /// <param name="xml">微信推送来的 XML 数据。</param>
+        /// <param name="encryptedMsg">如果解析成功，将返回解析后的 `Encrypt` 字段的值。</param>
+        /// <returns>指示是否是有效的 XML 内容。</returns>
+        public static bool TryParseXml(string xml, out string? encryptedMsg)
+        {
+            return TryParseXml(xml, out encryptedMsg, out _);
+        }
+
+        /// <summary>
+        /// 尝试解析微信推送过来的 XML 数据（仅适用于兼容模式或安全模式）。
+        /// </summary>
+        /// <param name="xml">微信推送来的 XML 数据。</param>
+        /// <param name="toUserName">如果解析成功，将返回解析后的 `ToUserName` 字段的值。</param>
+        /// <param name="encryptedMsg">如果解析成功，将返回解析后的 `Encrypt` 字段的值。</param>
+        /// <returns>指示是否是有效的 XML 内容。</returns>
+        public static bool TryParseXml(string xml, out string? encryptedMsg, out string? toUserName)
+        {
+            if (xml == null) throw new ArgumentNullException(nameof(xml));
+
+            encryptedMsg = null;
+            toUserName = null;
+
+            try
+            {
+                XmlDocument xmlDoc = new XmlDocument();
+                xmlDoc.XmlResolver = null;
+                xmlDoc.LoadXml(xml);
+
+                XmlNode? xmlRoot = xmlDoc.FirstChild;
+                if (xmlRoot == null)
+                    return false;
+
+                encryptedMsg = xmlRoot["Encrypt"]?.InnerText?.ToString();
+                toUserName = xmlRoot["ToUserName"]?.InnerText?.ToString();
+
+                return !string.IsNullOrEmpty(encryptedMsg);
+            }
+            catch (XmlException)
+            {
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// 将返回给微信的加密文本内容包装成 XML 格式（仅适用于安全模式）。
+        /// </summary>
+        /// <param name="sToken">微信后台设置的 Token。</param>
+        /// <param name="sMsgEncrypt">返回给微信的加密文本内容。</param>
+        /// <returns></returns>
+        public static string WrapXml(string sToken, string sMsgEncrypt)
+        {
+            if (sToken == null) throw new ArgumentNullException(nameof(sToken));
+            if (sMsgEncrypt == null) throw new ArgumentNullException(nameof(sMsgEncrypt));
+
+            string sTimestamp = DateTimeOffset.Now.ToLocalTime().ToUnixTimeSeconds().ToString();
+            string sNonce = DateTimeOffset.Now.Ticks.ToString("x");
+            string sMsgSign = GenerateSignature(sToken: sToken, sTimestamp: sTimestamp, sNonce: sNonce, sMsgEncrypt: sMsgEncrypt);
+            return WrapXml(sTimestamp: sTimestamp, sNonce: sNonce, sMsgEncrypt: sMsgEncrypt, sMsgSign: sMsgSign);
+        }
+
+        /// <summary>
+        /// 将返回给微信的加密文本内容包装成 XML 格式（仅适用于安全模式）。
+        /// </summary>
+        /// <param name="sTimestamp">返回给微信的时间戳字符串。</param>
+        /// <param name="sNonce">返回给微信的随机字符串。</param>
+        /// <param name="sMsgEncrypt">返回给微信的加密文本内容。</param>
+        /// <param name="sMsgSign">返回给微信的签名。</param>
+        /// <returns></returns>
+        public static string WrapXml(string sTimestamp, string sNonce, string sMsgEncrypt, string sMsgSign)
+        {
+            if (sTimestamp == null) throw new ArgumentNullException(nameof(sTimestamp));
+            if (sNonce == null) throw new ArgumentNullException(nameof(sNonce));
+            if (sMsgEncrypt == null) throw new ArgumentNullException(nameof(sMsgEncrypt));
+            if (sMsgSign == null) throw new ArgumentNullException(nameof(sMsgSign));
+
+            StringBuilder builder = new StringBuilder();
+            builder.AppendFormat("<xml>");
+            builder.AppendFormat("<TimeStamp><![CDATA[{0}]]></TimeStamp>", SecurityElement.Escape(sTimestamp));
+            builder.AppendFormat("<Nonce><![CDATA[{0}]]></Nonce>", SecurityElement.Escape(sNonce));
+            builder.AppendFormat("<Encrypt><![CDATA[{0}]]></Encrypt>", SecurityElement.Escape(sMsgEncrypt));
+            builder.AppendFormat("<MsgSignature><![CDATA[{0}]]></MsgSignature>", SecurityElement.Escape(sMsgSign));
+            builder.AppendFormat("</xml>");
+            return builder.ToString();
+        }
+    }
+}

src/SKIT.FlurlHttpClient.Wechat.OpenAI/WechatOpenAIClientOptions.cs

@@ -18,13 +18,28 @@
         public string Endpoints { get; set; } = WechatOpenAIEndpoints.DEFAULT;
 
         /// <summary>
-        /// 获取或设置微信智能对话 ClientId。
+        /// 获取或设置微信智能对话 ClientId。仅限第三方平台接入时使用。
         /// </summary>
-        public string ClientId { get; set; } = default!;
+        public string? ClientId { get; set; }
 
         /// <summary>
-        /// 获取或设置微信智能对话 ClientKey。
+        /// 获取或设置微信智能对话 ClientKey。仅限第三方平台接入时使用。
         /// </summary>
-        public string ClientKey { get; set; } = default!;
+        public string? ClientKey { get; set; }
+
+        /// <summary>
+        /// 获取或设置微信智能对话 AppId。仅限平台接入时使用。
+        /// </summary>
+        public string? AppId { get; set; }
+
+        /// <summary>
+        /// 获取或设置微信智能对话服务器推送的 EncodingAESKey。仅限平台接入时使用。
+        /// </summary>
+        public string? PushEncodingAESKey { get; set; }
+
+        /// <summary>
+        /// 获取或设置微信智能对话服务器推送的 Token。仅限平台接入时使用。
+        /// </summary>
+        public string? PushToken { get; set; }
     }
 }

src/SKIT.FlurlHttpClient.Wechat.OpenAI/WechatOpenAIEvent.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Xml.Serialization;
+
+namespace SKIT.FlurlHttpClient.Wechat.OpenAI
+{
+    /// <summary>
+    /// 表示微信智能对话 API 回调通知事件的基类。
+    /// </summary>
+    [Serializable]
+    public class WechatOpenAIEvent
+    {
+        public static class Serialization
+        {
+            [XmlRoot("xml")]
+            public interface IXmlSerializable
+            {
+            }
+        }
+
+        /// <summary>
+        /// 获取或设置 AppId。
+        /// </summary>
+        [XmlElement("appid", IsNullable = true)]
+        public string? AppId { get; set; }
+
+        /// <summary>
+        /// 获取或设置事件类型。
+        /// </summary>
+        [XmlElement("event", IsNullable = true)]
+        public string? Event { get; set; }
+
+        /// <summary>
+        /// 获取或设置消息创建时间戳。
+        /// </summary>
+        [XmlElement("createtime", IsNullable = true)]
+        public long? CreateTimestamp { get; set; }
+    }
+}