一步步写自己的SoapExtension（一）

最简单的代码

    public class ClientEngine : SoapExtension
    {
        Stream oldStream;
        Stream newStream;
        string actionName;
        /// <summary>
        /// 构造函数
        /// </summary>
        public ClientEngine()
        {
        }
        public override object GetInitializer(LogicalMethodInfo methodInfo,SoapExtensionAttribute attribute)
        {
            return attribute;
        }

        public override object GetInitializer(Type t)
        {            
            return null;
        }

        public override void Initialize(object initializer)
        {
           
        }

        public override void ProcessMessage(SoapMessage message)
        {
            switch (message.Stage)
            {
                case SoapMessageStage.BeforeSerialize:
                    this.actionName = message.Action;
                    break;
                case SoapMessageStage.AfterSerialize:
                    newStream.Position = 0;
                    Copy(newStream, oldStream);
                    break;
                case SoapMessageStage.BeforeDeserialize:
                    this.actionName = message.Action;
                    Copy(oldStream, newStream);
                    newStream.Position = 0;
                    break;
                case SoapMessageStage.AfterDeserialize: break;
                default:
                    throw new Exception("invalid stage");
            }
        }

        public override Stream ChainStream(Stream stream)
        {
            oldStream = stream;
            newStream = new MemoryStream();
            return newStream;
        }

        void Copy(Stream from, Stream to)
        {
            TextReader reader = new StreamReader(from);
            TextWriter writer = new StreamWriter(to);

            string strContent = reader.ReadToEnd();
            writer.Write(strContent);
            writer.Flush();
        }
    }

注意newStream.Position = 0;这个可是很重要，却很容易忽略。

客户端的app.config配置使用上面的类

  <system.web> 
    <webServices>
      <soapExtensionTypes>
        <add type="Ysd.Web.Security.ClientEngine, Ysd.Web.Security"
             priority="1" group="High" />
      </soapExtensionTypes>
    </webServices> 
  </system.web> 

客户端调用一下webservcie，你似乎没感觉到我们的类的存在。放断点在