ASP.NET Core中間件(Middleware)進階學習實現SOAP 解析。
本篇將介紹實現ASP.NET Core SOAP服務端解析,而不是ASP.NET Core整個WCF host。
因為WCF中不僅僅只是有SOAP, 它還包含很多如消息安全性,生成WSDL,雙工信道,非HTTP傳輸等。
ASP.NET Core 官方推薦大家使用RESTful Web API的解決方案提供網絡服務。
SOAP 即 Simple Object AccessProtocol 也就是簡單對象訪問協議。
SOAP 呢,其指導理念是“唯一一個沒有發明任何新技術的技術”,
是一種用於訪問 Web 服務的協議。
因為 SOAP 基於XML 和 HTTP ,其通過XML 來實現消息描述,然後再通過 HTTP 實現消息傳輸。
SOAP 是用於在應用程序之間進行通信的一種通信協議。
因為是基於 XML 和HTTP 的,所以其獨立於語言,獨立於平台,並且因為 XML 的擴展性很好,所以基於 XML 的 SOAP 自然擴展性也不差。
通過 SOAP 可以非常方便的解決互聯網中消息互聯互通的需求,其和其他的 Web 服務協議構建起 SOA 應用的技術基礎。
下面來正式開始 ASP.NET Core 實現SOAP 服務端解析。
首先新建一個ASP.NET Core Web Application -》 SOAPService 然後再模板裡選擇 Web API。
然後我們再添加一個Class Library -》 CustomMiddleware
下面我們來實現功能,首先在類庫項目中添加以下引用
Install-Package Microsoft.AspNetCore.Http.Abstractions Install-Package System.ServiceModel.Primitives Install-Package System.Reflection.TypeExtensions Install-Package System.ComponentModel
首先新建一個 ServiceDescription、ContractDescription和OperationDescription 類,這裡需要注意的是ServiceDescription,ContractDescription和OperationDescription這裡使用的是不能使用 System.ServiceModel.Description命名空間中的類型。它們是示例中簡單的新類型。
ServiceDescription.cs
public class ServiceDescription { public Type ServiceType { get; private set; } public IEnumerable<ContractDescription> Contracts { get; private set; } public IEnumerable<OperationDescription> Operations => Contracts.SelectMany(c => c.Operations); public ServiceDescription(Type serviceType) { ServiceType = serviceType; var contracts = new List<ContractDescription>(); foreach (var contractType in ServiceType.GetInterfaces()) { foreach (var serviceContract in contractType.GetTypeInfo().GetCustomAttributes<ServiceContractAttribute>()) { contracts.Add(new ContractDescription(this, contractType, serviceContract)); } } Contracts = contracts; } } View CodeContractDescription.cs
public class ContractDescription { public ServiceDescription Service { get; private set; } public string Name { get; private set; } public string Namespace { get; private set; } public Type ContractType { get; private set; } public IEnumerable<OperationDescription> Operations { get; private set; } public ContractDescription(ServiceDescription service, Type contractType, ServiceContractAttribute attribute) { Service = service; ContractType = contractType; Namespace = attribute.Namespace ?? "http://tempuri.org/"; // Namespace defaults to http://tempuri.org/ Name = attribute.Name ?? ContractType.Name; // Name defaults to the type name var operations = new List<OperationDescription>(); foreach (var operationMethodInfo in ContractType.GetTypeInfo().DeclaredMethods) { foreach (var operationContract in operationMethodInfo.GetCustomAttributes<OperationContractAttribute>()) { operations.Add(new OperationDescription(this, operationMethodInfo, operationContract)); } } Operations = operations; } } View CodeOperationDescription.cs
public class OperationDescription { public ContractDescription Contract { get; private set; } public string SoapAction { get; private set; } public string ReplyAction { get; private set; } public string Name { get; private set; } public MethodInfo DispatchMethod { get; private set; } public bool IsOneWay { get; private set; } public OperationDescription(ContractDescription contract, MethodInfo operationMethod, OperationContractAttribute contractAttribute) { Contract = contract; Name = contractAttribute.Name ?? operationMethod.Name; SoapAction = contractAttribute.Action ?? $"{contract.Namespace.TrimEnd('/')}/{contract.Name}/{Name}"; IsOneWay = contractAttribute.IsOneWay; ReplyAction = contractAttribute.ReplyAction; DispatchMethod = operationMethod; } } View Code
添加完成後下面來新建一個中間件 SOAPMiddleware ,對於新建中間件可以參考我之前的文章:http://www.cnblogs.com/linezero/p/5529767.html
SOAPMiddleware.cs 代碼如下:
public class SOAPMiddleware { private readonly RequestDelegate _next; private readonly Type _serviceType; private readonly string _endpointPath; private readonly MessageEncoder _messageEncoder; private readonly ServiceDescription _service; private IServiceProvider serviceProvider; public SOAPMiddleware(RequestDelegate next, Type serviceType, string path, MessageEncoder encoder,IServiceProvider _serviceProvider) { _next = next; _serviceType = serviceType; _endpointPath = path; _messageEncoder = encoder; _service = new ServiceDescription(serviceType); serviceProvider = _serviceProvider; } public async Task Invoke(HttpContext httpContext) { if (httpContext.Request.Path.Equals(_endpointPath, StringComparison.Ordinal)) { Message responseMessage; //讀取Request請求信息 var requestMessage = _messageEncoder.ReadMessage(httpContext.Request.Body, 0x10000, httpContext.Request.ContentType); var soapAction = httpContext.Request.Headers["SOAPAction"].ToString().Trim('\"'); if (!string.IsNullOrEmpty(soapAction)) { requestMessage.Headers.Action = soapAction; } //獲取操作 var operation = _service.Operations.Where(o => o.SoapAction.Equals(requestMessage.Headers.Action, StringComparison.Ordinal)).FirstOrDefault(); if (operation == null) { throw new InvalidOperationException($"No operation found for specified action: {requestMessage.Headers.Action}"); } //獲取注入的服務 var serviceInstance = serviceProvider.GetService(_service.ServiceType); //獲取操作的參數信息 var arguments = GetRequestArguments(requestMessage, operation); // 執行操作方法 var responseObject = operation.DispatchMethod.Invoke(serviceInstance, arguments.ToArray()); var resultName = operation.DispatchMethod.ReturnParameter.GetCustomAttribute<MessageParameterAttribute>()?.Name ?? operation.Name + "Result"; var bodyWriter = new ServiceBodyWriter(operation.Contract.Namespace, operation.Name + "Response", resultName, responseObject); responseMessage = Message.CreateMessage(_messageEncoder.MessageVersion, operation.ReplyAction, bodyWriter); httpContext.Response.ContentType = httpContext.Request.ContentType; httpContext.Response.Headers["SOAPAction"] = responseMessage.Headers.Action; _messageEncoder.WriteMessage(responseMessage, httpContext.Response.Body); } else { await _next(httpContext); } } private object[] GetRequestArguments(Message requestMessage, OperationDescription operation) { var parameters = operation.DispatchMethod.GetParameters(); var arguments = new List<object>(); // 反序列化請求包和對象 using (var xmlReader = requestMessage.GetReaderAtBodyContents()) { // 查找的操作數據的元素 xmlReader.ReadStartElement(operation.Name, operation.Contract.Namespace); for (int i = 0; i < parameters.Length; i++) { var parameterName = parameters[i].GetCustomAttribute<MessageParameterAttribute>()?.Name ?? parameters[i].Name; xmlReader.MoveToStartElement(parameterName, operation.Contract.Namespace); if (xmlReader.IsStartElement(parameterName, operation.Contract.Namespace)) { var serializer = new DataContractSerializer(parameters[i].ParameterType, parameterName, operation.Contract.Namespace); arguments.Add(serializer.ReadObject(xmlReader, verifyObjectName: true)); } } } return arguments.ToArray(); } } public static class SOAPMiddlewareExtensions { public static IApplicationBuilder UseSOAPMiddleware<T>(this IApplicationBuilder builder, string path, MessageEncoder encoder) { return builder.UseMiddleware<SOAPMiddleware>(typeof(T), path, encoder); } public static IApplicationBuilder UseSOAPMiddleware<T>(this IApplicationBuilder builder, string path, Binding binding) { var encoder = binding.CreateBindingElements().Find<MessageEncodingBindingElement>()?.CreateMessageEncoderFactory().Encoder; return builder.UseMiddleware<SOAPMiddleware>(typeof(T), path, encoder); } }
這裡對於輸出的消息做了一個封裝,以輸出具有正確的元素名稱的消息的主體。
添加一個 ServiceBodyWriter 類。
public class ServiceBodyWriter : BodyWriter { string ServiceNamespace; string EnvelopeName; string ResultName; object Result; public ServiceBodyWriter(string serviceNamespace, string envelopeName, string resultName, object result) : base(isBuffered: true) { ServiceNamespace = serviceNamespace; EnvelopeName = envelopeName; ResultName = resultName; Result = result; } protected override void OnWriteBodyContents(XmlDictionaryWriter writer) { writer.WriteStartElement(EnvelopeName, ServiceNamespace); var serializer = new DataContractSerializer(Result.GetType(), ResultName, ServiceNamespace); serializer.WriteObject(writer, Result); writer.WriteEndElement(); } } View Code這裡對於中間件整個就完成了。
在服務端使用,這裡你也可以新建一個Web 項目。
因為剛剛我們已經新建好了一個Web API項目,我們就直接拿來使用。
首先添加 CustomMiddleware 引用
在 SOAPService 中添加一個 CalculatorService 類
public class CalculatorService : ICalculatorService { public double Add(double x, double y) => x + y; public double Divide(double x, double y) => x / y; public double Multiply(double x, double y) => x * y; public double Subtract(double x, double y) => x - y; public string Get(string str) => $"{str} Hello World!"; } [ServiceContract] public interface ICalculatorService { [OperationContract] double Add(double x, double y); [OperationContract] double Subtract(double x, double y); [OperationContract] double Multiply(double x, double y); [OperationContract] double Divide(double x, double y); [OperationContract] string Get(string str); }
這裡我為了方便將接口契約也放在CalculatorService 中,你也可以新建一個接口。
然後在 Startup.cs 的 ConfigureServices 中注入 CalculatorService
public void ConfigureServices(IServiceCollection services) { // Add framework services. services.AddMvc(); services.AddScoped<CalculatorService>(); }
在Configure 方法中加入中間件
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory) { loggerFactory.AddConsole(Configuration.GetSection("Logging")); loggerFactory.AddDebug(); //加入一個/CalculatorService.svc 地址,綁定Http app.UseSOAPMiddleware<CalculatorService>("/CalculatorService.svc", new BasicHttpBinding()); app.UseMvc(); }
這樣就完成了服務端編寫。
新建一個 Console Application -》SOAPClient
添加如下引用:
Install-Package System.ServiceModel.Primitives Install-Package System.Private.ServiceModel Install-Package System.ServiceModel.Http
Program代碼如下:
public class Program { public static void Main(string[] args) { Random numGen = new Random(); double x = numGen.NextDouble() * 20; double y = numGen.NextDouble() * 20; var serviceAddress = "http://localhost:5000/CalculatorService.svc"; var client = new CalculatorServiceClient(new BasicHttpBinding(), new EndpointAddress(serviceAddress)); Console.WriteLine($"{x} + {y} == {client.Add(x, y)}"); Console.WriteLine($"{x} - {y} == {client.Subtract(x, y)}"); Console.WriteLine($"{x} * {y} == {client.Multiply(x, y)}"); Console.WriteLine($"{x} / {y} == {client.Divide(x, y)}"); client.Get("Client"); } } class CalculatorServiceClient : ClientBase<ICalculatorService> { public CalculatorServiceClient(Binding binding, EndpointAddress remoteAddress) : base(binding, remoteAddress) { } public double Add(double x, double y) => Channel.Add(x, y); public double Subtract(double x, double y) => Channel.Subtract(x, y); public double Multiply(double x, double y) => Channel.Multiply(x, y); public double Divide(double x, double y) => Channel.Divide(x, y); public void Get(string str) { Console.WriteLine(Channel.Get(str)); } } [ServiceContract] public interface ICalculatorService { [OperationContract] double Add(double x, double y); [OperationContract] double Subtract(double x, double y); [OperationContract] double Multiply(double x, double y); [OperationContract] double Divide(double x, double y); [OperationContract] string Get(string str); }
編寫好以後,分別對應到目錄使用dotnet run執行程序。
成功建立了連接,也有返回。也就實現SOAP 的解析。
示例代碼GitHub:https://github.com/linezero/Blog/tree/master/SOAPService
參考文檔:https://blogs.msdn.microsoft.com/dotnet/2016/09/19/custom-asp-net-core-middleware-example/