微信公众平台的消息处理还是比较完善的，有最基本的文本消息，到图文消息，到图片消息，语音消息，视频消息，音乐消息其基本原理都是一样的，只不过所post的xml数据有所差别，在处理消息之前，我们要认真阅读，官方给我们的文档：。首先我们从最基本的文本消息处理开始。
<xml> <ToUserName><![CDATA[toUser]]></ToUserName> <FromUserName><![CDATA[fromUser]]></FromUserName> <CreateTime>12345678</CreateTime> <MsgType><![CDATA[text]]></MsgType> <Content><![CDATA[你好]]></Content> </xml>
我们可以看到这是消息处理的一个最基本的模式，有发送者，接受者，创建时间，类型，内容等等。
首先我们来创建一个消息处理的类，这个类用来捕获，所有的消息请求，根据不同的消息请求类型来处理不同的消息回复。
public class WeiXinService { /// <summary> /// TOKEN /// </summary> private const string TOKEN = "finder"; /// <summary> /// 签名 /// </summary> private const string SIGNATURE = "signature"; /// <summary> /// 时间戳 /// </summary> private const string TIMESTAMP = "timestamp"; /// <summary> /// 随机数 /// </summary> private const string NONCE = "nonce"; /// <summary> /// 随机字符串 /// </summary> private const string ECHOSTR = "echostr"; /// <summary> /// /// </summary> private HttpRequest Request { get; set; } /// <summary> /// 构造函数 /// </summary> /// <param></param> public WeiXinService(HttpRequest request) { this.Request = request; } /// <summary> /// 处理请求，产生响应 /// </summary> /// <returns></returns> public string Response() { string method = Request.HttpMethod.ToUpper(); //验证签名 if (method == "GET") { if (CheckSignature()) { return Request.QueryString[ECHOSTR]; } else { return "error"; } } //处理消息 if (method == "POST") { return ResponseMsg(); } else { return "无法处理"; } } /// <summary> /// 处理请求 /// </summary> /// <returns></returns> private string ResponseMsg() { string requestXml = CommonWeiXin.ReadRequest(this.Request); IHandler handler = HandlerFactory.CreateHandler(requestXml); if (handler != null) { return handler.HandleRequest(); } return string.Empty; } /// <summary> /// 检查签名 /// </summary> /// <param></param> /// <returns></returns> private bool CheckSignature() { string signature = Request.QueryString[SIGNATURE]; string timestamp = Request.QueryString[TIMESTAMP]; string nonce = Request.QueryString[NONCE]; List<string> list = new List<string>(); list.Add(TOKEN); list.Add(timestamp); list.Add(nonce); //排序 list.Sort(); //拼串 string input = string.Empty; foreach (var item in list) { input += item; } //加密 string new_signature = SecurityUtility.SHA1Encrypt(input); //验证 if (new_signature == signature) { return true; } else { return false; } } }
在来看看我们的首先是如何捕获消息的。首页Default.ashx的代码如下
public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/html"; string postString = string.Empty; if (HttpContext.Current.Request.HttpMethod.ToUpper() == "POST") { //由微信服务接收请求，具体处理请求 WeiXinService wxService = new WeiXinService(context.Request); string responseMsg = wxService.Response(); context.Response.Clear(); context.Response.Charset = "UTF-8"; context.Response.Write(responseMsg); context.Response.End(); } else { string token = "wei2414201"; if (string.IsNullOrEmpty(token)) { return; } string echoString = HttpContext.Current.Request.QueryString["echoStr"]; string signature = HttpContext.Current.Request.QueryString["signature"]; string timestamp = HttpContext.Current.Request.QueryString["timestamp"]; string nonce = HttpContext.Current.Request.QueryString["nonce"]; if (!string.IsNullOrEmpty(echoString)) { HttpContext.Current.Response.Write(echoString); HttpContext.Current.Response.End(); } } }
从上面的代码中我们可以看到WeiXinService.cs类中的消息相应至关重要。
/// <summary> /// 处理请求 /// </summary> /// <returns></returns> private string ResponseMsg() { string requestXml = CommonWeiXin.ReadRequest(this.Request); IHandler handler = HandlerFactory.CreateHandler(requestXml); if (handler != null) { return handler.HandleRequest(); } return string.Empty; }
IHandler是一个消息处理接口，其下面有EventHandler，TextHandler处理类实现这个接口。代码如下
/// <summary> /// 处理接口 /// </summary> public interface IHandler { /// <summary> /// 处理请求 /// </summary> /// <returns></returns> string HandleRequest(); }
EventHandler