使用C#调用Java带MIME附件WebService方法的初步设想

    朋友说开发电信的MMS，其实需要图片作为附件放在调用WebService接口上，使用Http的Content-Type: Multipart/Related;来发送，真让人感觉不伦不类的。不知道为什么不设计成一个字段是BASE64编码得了呗。

    难道只能用朋友说的拼字段的方法了不？ 我用Reflect分析了一下，貌似这样也可以实现。

    我们知道，我们添加一个WebService引用时，会自动生成从  SoapHttpClientProtocol 的子类。我的想法是，我们写一个 继承自"SoapHttpClientProtocol” 的子类SoapHttpClientProtocolEX, 重写方法：GetWebRequest() 返回我们写的代码 HttpWebRequestEx类，然后在原始 HttpWebRequest 类的GetRequestStream()时，返回我们的流转移器：NetwordStreamEx ，并在方法关闭流 Close() 前，加入自定义的附件信息。

    不知道说清楚没有， 这里列了部分代码框架：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web.Services.Protocols;
using System.Net;
using System.Net.Sockets;
using System.IO;

namespace Foundway.Util.WebService
{
    public class SoapHttpClientProtocolEx : SoapHttpClientProtocol
    {
        private List<string> attachments = new List<string>();


        /// <summary>
        /// 添加一个附件
        /// </summary>
        /// <param name="attachment">附件全路径</param>
        public void AddAttachment(string attachment)
        {
            attachments.Add(attachment);
        }

        protected override  WebRequest GetWebRequest(Uri uri)
        {
            WebRequest request =   base.GetWebRequest(uri);
            if (attachments.Count > 0)
            {
                HttpWebRequest httpRequest = request as HttpWebRequest;
                if (httpRequest != null)
                {
                    httpRequest.SendChunked = true; //使用多段发送

                    HttpWebRequestEx httpRequestEx = new HttpWebRequestEx(httpRequest, attachments.ToArray());
                    return httpRequestEx;
                }
            }
            return request;


        }
    }

    public class HttpWebRequestEx : WebRequest
    {
        private string[] attachments;
        private HttpWebRequest httpRequest = null;

        public HttpWebRequestEx(HttpWebRequest httpRequest, string[] attachments)
        {
            this.httpRequest = httpRequest;
            this.attachments = attachments;

        }


        public override System.IO.Stream GetRequestStream()
        {
            Stream stream = httpRequest.GetRequestStream();
            //返回自定义的流代理，来完成附件的信息
            return new NetworkStreamEx(stream, this.attachments);
        }

        #region 重写其它全部公共方法

        public override void Abort()
        {
            httpRequest.Abort();
        }

        public override IAsyncResult BeginGetRequestStream(AsyncCallback callback, object state)
        {
            return httpRequest.BeginGetRequestStream(callback, state);
        }

        public override IAsyncResult BeginGetResponse(AsyncCallback callback, object state)
        {
            return httpRequest.BeginGetResponse(callback, state);
        }

        public override System.Net.Cache.RequestCachePolicy CachePolicy
        {
            get
            {
                return httpRequest.CachePolicy;
            }
            set
            {
                httpRequest.CachePolicy = value;
            }
        }

        public override string ConnectionGroupName
        {
            get
            {
                return httpRequest.ConnectionGroupName;
            }
            set
            {
                httpRequest.ConnectionGroupName = value;
            }
        }

        public override long ContentLength
        {
            get
            {
                return httpRequest.ContentLength;
            }
            set
            {
                httpRequest.ContentLength = value;
            }
        }

        public override string ContentType
        {
            get
            {
                return httpRequest.ContentType;
            }
            set
            {
                httpRequest.ContentType = value;
            }
        }

        public override System.Runtime.Remoting.ObjRef CreateObjRef(Type requestedType)
        {
            return httpRequest.CreateObjRef(requestedType);
        }

        public override ICredentials Credentials
        {
            get
            {
                return httpRequest.Credentials;
            }
            set
            {
                httpRequest.Credentials = value;
            }
        }

        public override Stream EndGetRequestStream(IAsyncResult asyncResult)
        {
            return httpRequest.EndGetRequestStream(asyncResult);
        }

        public override WebResponse EndGetResponse(IAsyncResult asyncResult)
        {
            return httpRequest.EndGetResponse(asyncResult);
        }

        public override WebResponse GetResponse()
        {
            return httpRequest.GetResponse();
        }

        public override WebHeaderCollection Headers
        {
            get
            {
                return httpRequest.Headers;
            }
            set
            {
                httpRequest.Headers = value;
            }
        }


        public override string Method
        {
            get
            {
                return httpRequest.Method;
            }
            set
            {
                httpRequest.Method = value;
            }
        }

        public override bool PreAuthenticate
        {
            get
            {
                return httpRequest.PreAuthenticate;
            }
            set
            {
                httpRequest.PreAuthenticate = value;
            }
        }

        public override IWebProxy Proxy
        {
            get
            {
                return httpRequest.Proxy;
            }
            set
            {
                httpRequest.Proxy = value;
            }
        }

        public override object InitializeLifetimeService()
        {
            return httpRequest.InitializeLifetimeService();
        }

        public override Uri RequestUri
        {
            get
            {
                return httpRequest.RequestUri;
            }
        }

        public override int Timeout
        {
            get
            {
                return httpRequest.Timeout;
            }
            set
            {
                httpRequest.Timeout = value;
            }
        }

        public override string ToString()
        {
            return httpRequest.ToString();
        }

        public override bool UseDefaultCredentials
        {
            get
            {
                return httpRequest.UseDefaultCredentials;
            }
            set
            {
                httpRequest.UseDefaultCredentials = value;
            }
        }
        public override bool Equals(object obj)
        {
            return httpRequest.Equals(obj);
        }

        public override int GetHashCode()
        {
            return httpRequest.GetHashCode();
        }

        #endregion


    }

    public class NetworkStreamEx :Stream
    {
        private string[] attachments;
        private Stream baseStream;
        
        public NetworkStreamEx(Stream baseStream, string[] attachments)
        {
            this.baseStream = baseStream;
        }


        /// <summary>
        /// 在关闭时，加入附件信息
        /// </summary>
        public override void Close()
        {
            ///TODO:这里添加附件信息，
            ///这里就不加代码了
            ///

            base.Close();
        }

        #region 把其它公共方法转发到原流

        public override bool CanRead
        {
            get { return baseStream.CanRead; }
        }

        public override bool CanSeek
        {
            get { return baseStream.CanSeek; }
        }

        public override bool CanWrite
        {
            get { return baseStream.CanWrite; }
        }

        public override void Flush()
        {
            baseStream.Flush();
        }

        public override long Length
        {
            get { return baseStream.Length; }
        }

        public override long Position
        {
            get
            {
                return baseStream.Position;
            }
            set
            {
                baseStream.Position  = value;
            }
        }

        public override int Read(byte[] buffer, int offset, int count)
        {
            return baseStream.Read(buffer, offset, count);
        }

        public override long Seek(long offset, SeekOrigin origin)
        {
            return baseStream.Seek(offset, origin);
        }

        public override void SetLength(long value)
        {
            baseStream.SetLength(value);
        }

        public override void Write(byte[] buffer, int offset, int count)
        {
            baseStream.Write(buffer, offset, count);
        }

        #endregion
    }
    
}

引自：51aspx