又封周末，闲暇无聊，随手写了一个关于微信公众号服务的中间件，基于.NetCore2.1。服务类库采用.Net Standard2.0，兼容.net 4.6.1。
整体思路是，设计一个中间件，提供微信消息推送服务。目前实现了，接收微信消息推送后，根据消息类型，对事件消息和被动接收消息分别进行了处理。
在中间件和服务之间，创建一个服务提供类，拥有提供消息的处理逻辑，开发者，可以实现服务提供接口，完成自己的逻辑。下面，让我们看看关于中间件的代码设计：
这里，我新建了一个名为WeiXinMiddleware的类，代码如下：
/// <summary> /// <![CDATA[微信中间件]]> /// </summary> public class WeiXinMiddleware { /// <summary> /// /// </summary> private RequestDelegate Next = null; /// <summary> /// <![CDATA[配置]]> /// </summary> public IConfiguration Configuration { get; } /// <summary> /// <![CDATA[中间件配置信息]]> /// </summary> public OAuth.WeiXinServerOptions ServerOptions { get; set; } /// <summary> /// <![CDATA[构造]]> /// </summary> /// <param name="requestDelegate"></param> /// <param name="configuration"></param> public WeiXinMiddleware(RequestDelegate requestDelegate, IConfiguration configuration, OAuth.WeiXinServerOptions serverOptions) { Next = requestDelegate; Configuration = configuration; ServerOptions = serverOptions; } /// <summary> /// <![CDATA[调用]]> /// </summary> /// <param name="context"></param> /// <returns></returns> public async Task Invoke(HttpContext context) {if (context.Request.Path == ServerOptions.NotifyPath) { //微信服务 if (ServerOptions.WeiXinServerProvider == null) ServerOptions.WeiXinServerProvider = (OAuth.IWeiXinServerProvider)context.RequestServices.GetService(typeof(OAuth.IWeiXinServerProvider)); await ServerOptions.WeiXinServerProvider.Run(context, Configuration); return; } await Next.Invoke(context); } }
代码其实很简单，就是在类内部定义一个Invoke任务，再声明一个Next属性，用于请求的下一步处理委托。在中间件的构造函数中，进行了注入，其中有一个
WeiXinServerOptions 类，它便是定义中间件所需的配置信息，也是对外提供的接口，让我们看看具体的代码：
/// <summary> /// /// </summary> public class WeiXinServerOptions { /// <summary> ///<![CDATA[微信通知地址]]> /// </summary> public PathString NotifyPath { get; set; } /// <summary> /// /// </summary> private IWeiXinServerProvider _ServerProvider = null; /// <summary> /// <![CDATA[微信服务提供程序]]> /// </summary> public IWeiXinServerProvider WeiXinServerProvider { get { return _ServerProvider; } set { _ServerProvider = value; _ServerProvider.ServerOptions = this; } } /// <summary> /// <![CDATA[当接收到消息时]]> /// </summary> public Func<HttpContext, Task> OnRecieveAsync { get; set; } /// <summary> /// <![CDATA[扫描事件]]> /// </summary> public Func<WeiXinContext, Task> OnScanAsync { get; set; } /// <summary> /// <![CDATA[关注事件]]> /// </summary> public Func<WeiXinContext, Task> OnSubscribeAsync { get; set; } /// <summary> /// <![CDATA[取消关注]]> /// </summary> public Func<WeiXinContext, Task> OnUnsubscribeAsync { get; set; } /// <summary> /// <![CDATA[菜单点击事件]]> /// </summary> public Func<WeiXinContext, Task> OnClickAsync { get; set; } /// <summary> /// <![CDATA[点击链接]]> /// </summary> public Func<WeiXinContext, Task> OnViewAsync { get; set; } /// <summary> /// <![CDATA[上报地理位置]]> /// </summary> public Func<WeiXinContext, Task> OnLocationAsync { get; set; } /// <summary> /// <![CDATA[被动接收普通消息]]> /// </summary> public Func<HttpContext, Task> OnRecieveMessageAsync { get; set; } }
这个类中，定义了中间件要拦截处理的URL，以及时间消息的处理委托，有了这些委托，我们就可以很灵活的实现在接收到微信推送消息后的逻辑处理。
这个类中，还定义了一个WeiXinServerProvider属性，它是接口IWeiXinServerProvider的派生，让我们看看它定义的成员吧！
public interface IWeiXinServerProvider { /// <summary> /// /// </summary> OAuth.WeiXinServerOptions ServerOptions { get; set; } /// <summary> /// /// </summary> /// <param name="context"></param> /// <param name="configuration"></param> /// <param name="serverOptions"></param> /// <returns></returns> Task Run(HttpContext context, IConfiguration configuration); }
很简单吧，一个属性，一个运行任务的函数。
上面几个类是我服务的核心，下面我又创建了2个扩展类，分别为添加中间件和IOC注入服务。
/// <summary> /// <![CDATA[微信中间件扩展]]> /// </summary> public static class WeiXinMiddlewareExtensions { /// <summary> /// <![CDATA[]]> /// </summary> /// <param name="app"></param> /// <param name="serverOptions"></param> public static void UseWeiXinServer(this IApplicationBuilder app, OAuth.WeiXinServerOptions serverOptions) { app.UseMiddleware<Middleware.WeiXinMiddleware>(serverOptions); } }
下面是IOC注入的扩展方法：
/// <summary> /// /// </summary> public static class WeiXinServiceCollectionExtensions { /// <summary> /// /// </summary> /// <param name="services"></param> public static void AddWeiXinServer(this IServiceCollection services) { services.AddSingleton(typeof(OAuth.IWeiXinServerProvider), typeof(OAuth.WeiXinServer));//单例：IOC注册服务类型 } }
完成以上代码后，最后让我们再Start类中，进行服务的配置。
public class Startup { public Startup(IConfiguration configuration) { Configuration = configuration; } public IConfiguration Configuration { get; } // This method gets called by the runtime. Use this method to add services to the container. public void ConfigureServices(IServiceCollection services) { services.Configure<CookiePolicyOptions>(options => { // This lambda determines whether user consent for non-essential cookies is needed for a given request. options.CheckConsentNeeded = context => true; options.MinimumSameSitePolicy = SameSiteMode.None; }); services.AddWeiXinServer();//IOC注册服务类型 services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1); } /// <summary> /// /// </summary> /// <param name="app"></param> /// <param name="env"></param> public void Configure(IApplicationBuilder app, IHostingEnvironment env) { if (env.IsDevelopment()) { app.UseDeveloperExceptionPage(); } else { app.UseExceptionHandler("/Home/Error"); app.UseHsts(); } //使用微信中间件 app.UseWeiXinServer(new OAuth.WeiXinServerOptions() { NotifyPath = new PathString("/OAuth/WeiXin"), //WeiXinServerProvider = new OAuth.WeiXinServer(),//此处也可也手动设置，默认通过IOC容器创建WeiXinServer实例。 OnScanAsync = (context) => { return Task.Delay(0); }, OnClickAsync = (context) => { return Task.Delay(0); }, OnSubscribeAsync = (context) => { return Task.Delay(0); }, OnUnsubscribeAsync = (context) => { return Task.Delay(0); }, OnViewAsync = (context) => { return Task.Delay(0); }, OnRecieveMessageAsync = (context) => { return Task.Delay(0); }, }); app.UseStaticFiles(); app.UseCookiePolicy(); app.UseMvc(routes => { routes.MapRoute( name: "default", template: "{controller=Home}/{action=Index}/{id?}"); }); } }
让我们再看看WeiXinServer类的定义：
/// <summary> /// <![CDATA[微信服务]]> /// </summary> public class WeiXinServer : IWeiXinServerProvider { /// <summary> /// <![CDATA[服务选项]]> /// </summary> public OAuth.WeiXinServerOptions ServerOptions { get; set; } /// <summary> /// /// </summary> public WeiXinServer() { } /// <summary> /// <![CDATA[运行服务]]> /// </summary> /// <param name="context"></param> /// <param name="configuration"></param> /// <param name="serverOptions"></param> /// <returns></returns> public async Task Run(HttpContext context, IConfiguration configuration) { #region 1、验证签名 if (context.Request.Method.ToUpper() == "GET") { context.Response.ContentType = "text/plain;charset=utf-8"; context.Response.StatusCode = 200; //1、验证签名 if (WeiXin.Sdk.Common.Util.CheckSignature(context.Request.Query["nonce"], context.Request.Query["timestamp"], context.Request.Query["signature"], configuration.GetSection("WeiXinOAuth")["Token"])) { await context.Response.WriteAsync(context.Request.Query["echostr"]); return; } await context.Response.WriteAsync("无效签名！"); return; } #endregion 1、验证签名 #region 2、接收微信消息 await OnRecieve(context);//接收消息 #endregion 2、接收微信消息 } #region 虚方法 /// <summary> /// <![CDATA[虚方法，接收消息后处理]]> /// </summary> /// <param name="context"></param> /// <returns></returns> public virtual Task OnRecieve(HttpContext context) { if (ServerOptions.OnRecieveAsync != null) return ServerOptions.OnRecieveAsync(context); string strRecieveBody = null;//接收消息 using (System.IO.StreamReader streamReader = new System.IO.StreamReader(context.Request.Body)) { strRecieveBody = streamReader.ReadToEndAsync().GetAwaiter().GetResult(); } //序列化 WeiXin.Sdk.Common.Serialization.XmlSerializer xmlSerializer = new WeiXin.Sdk.Common.Serialization.XmlSerializer(typeof(WeiXin.Sdk.Domain.Messages.Message)); var recieve = (WeiXin.Sdk.Domain.Messages.Message)xmlSerializer.Deserialize(strRecieveBody); //事件消息 if (recieve.MsgType == WeiXin.Sdk.Common.Constants.SystemConstants.MSG_TYPE.EVENT) { var weiXinContext = new WeiXinContext(recieve, context);
var weiXinContext = new WeiXinContext(recieve, context);
var actionName = recieve.Event.ToLower();
actionName = actionName.First().ToString().ToUpper() + actionName.Substring(1);
var action = this.GetType().GetMethod($"On{actionName}");
if (action != null) return (Task)action.Invoke(this, new object[] { weiXinContext });
} //被动接收消息 else { return OnRecieveMessage(context); } return Task.Delay(0); } /// <summary> /// <![CDATA[被动接收消息]]> /// </summary> /// <param name="context"></param> /// <returns></returns> public virtual Task OnRecieveMessage(HttpContext context) { if (ServerOptions.OnRecieveMessageAsync != null) return ServerOptions.OnRecieveMessageAsync(context); return Task.Delay(0); } /// <summary> /// <![CDATA[扫描事件]]> /// </summary> /// <param name="context"></param> /// <returns></returns> public virtual Task OnScan(WeiXinContext context) { if (ServerOptions.OnScanAsync != null) return ServerOptions.OnScanAsync(context); return Task.Delay(0); } /// <summary> /// <![CDATA[关注事件]]> /// </summary> /// <param name="context"></param> /// <returns></returns> public virtual Task OnSubscribe(WeiXinContext context) { if (ServerOptions.OnSubscribeAsync != null) return ServerOptions.OnSubscribeAsync(context); return Task.Delay(0); } /// <summary> /// <![CDATA[取消关注]]> /// </summary> /// <param name="context"></param> /// <returns></returns> public virtual Task OnUnsubscribe(WeiXinContext context) { if (ServerOptions.OnUnsubscribeAsync != null) return ServerOptions.OnUnsubscribeAsync(context); return Task.Delay(0); } /// <summary> /// <![CDATA[菜单点击]]> /// </summary> /// <param name="context"></param> /// <returns></returns> public virtual Task OnClick(WeiXinContext context) { if (ServerOptions.OnClickAsync != null) return ServerOptions.OnClickAsync(context); return Task.Delay(0); } /// <summary> /// <![CDATA[点击菜单链接]]> /// </summary> /// <param name="context"></param> /// <returns></returns> public virtual Task OnView(WeiXinContext context) { if (ServerOptions.OnViewAsync != null) return ServerOptions.OnViewAsync(context); return Task.Delay(0); } /// <summary> /// <![CDATA[上报地理位置]]> /// </summary> /// <param name="context"></param> /// <returns></returns> public virtual Task OnLocation(WeiXinContext context) { if (ServerOptions.OnLocationAsync != null) return ServerOptions.OnLocationAsync(context); return Task.Delay(0); } #endregion }
WeiXinServer类中还定义了时间消息的相关的虚方法，虚方法中，调用Options配置中定义的委托，这样，开发者一方面可以通过继承WeiXinServer或IWeiXinServerProvider接口，或通过设置Options属性，来灵活运用，开发者可根据自身需求，完成
对应业务逻辑即可。有了这些设计，我们可以轻松配置和完成微信消息的处理。
以上内容的全部代码，可以通过访问https://gitee.com/lichaoqiang/weixinmd 获取，不足之处，还望不吝赐教。