实现一个压缩Remoting传输数据的Sink:CompressionSink

在前两讲《初探.Net Remoting服务端 Loading Remtoing配置内容的过程 》《初探.Net Remoting客户端 Loading Remtoing配置内容的过程 》中,我已经分析了Remoting 的Sink机制，接下来，就提供一个具体的范例：CompressionSink（原始SourceCode源于Advanced .Net Remoting 1StED）。 CompressionSink通过在客户端和服务端各自插入一个数据压缩-解压缩的Sink。目的是希望减少大数据量传递对网络带宽的占用，提高传输效率。下载SourceCode ,BTW,这个压缩Sink相对比较稳定，大家可以在各自的项目中放心使用。:-)



详细设计：
提供一个Assembly：　CompressionSink.dll
它包括：
    客户端：
        CompressionSink.CompressionClientSinkProvider类和CompressionSink.CompressionClientSink类
    服务端：
        CompressionSink.CompressionServerSinkProvider类和CompressionSink.CompressionServerSink类
    压缩类：CompressionHelper
    压缩内核：NZipLib库。

客户端的配置文件 ：

<?xml version="1.0" encoding="utf-8" ?>

<configuration>

    <system.runtime.remoting>

        <application>

            <channels>

                <channel ref="http">

                    <clientProviders>

                        <formatter ref="soap" />

                        <provider type="CompressionSink.CompressionClientSinkProvider, CompressionSink" />

                    </clientProviders>

                </channel>

            </channels>

             <client>

                 <wellknown type="Service.SomeSAO, Service"  url="http://localhost:5555/SomeSAO.soap" />

             </client>

        </application>

    </system.runtime.remoting>

</configuration>

服务端的配置文件 ：  

<?xml version="1.0" encoding="utf-8" ?>

<configuration>

    <system.runtime.remoting>

        <application>

            <channels>

                <channel ref="http" port="5555">

                    <serverProviders>

                        <provider type="CompressionSink.CompressionServerSinkProvider, CompressionSink" />

                        <formatter ref="soap"/>

                    </serverProviders>

                </channel>

            </channels>

            <service>

                <wellknown mode="Singleton"  type="Service.SomeSAO, Service"   objectUri="SomeSAO.soap" />

            </service>

        </application>

    </system.runtime.remoting>

</configuration>

 

public   class  CompressionClientSinkProvider: IClientChannelSinkProvider
     {
        private IClientChannelSinkProvider _nextProvider;

        public CompressionClientSinkProvider(IDictionary properties, ICollection providerData) 
        {
            // not yet needed
        }

        public IClientChannelSinkProvider Next
        {
            get {
                return _nextProvider;
            }
            set {
                _nextProvider = value;
            }
        }

        public IClientChannelSink CreateSink(IChannelSender channel, string url, object remoteChannelData) 
        {
            // create other sinks in the chain
            IClientChannelSink next = _nextProvider.CreateSink(channel,
                url,
                remoteChannelData);    
    
            // put our sink on top of the chain and return it                
            return new CompressionClientSink(next);
        }
    }

 1 public   class  CompressionClientSink: BaseChannelSinkWithProperties, 
 2                                         IClientChannelSink
 3      {
 4        private IClientChannelSink _nextSink;
 5
 6        public CompressionClientSink(IClientChannelSink next) 
 7        {
 8            _nextSink = next;
 9        }
10
11        public IClientChannelSink NextChannelSink 
12        {
13            get {
14                return _nextSink;
15            }
16        }
17
18
19        public void AsyncProcessRequest(IClientChannelSinkStack sinkStack, 
20                                        IMessage msg, 
21                                        ITransportHeaders headers, 
22                                        Stream stream) 
23        {
24
25
26            // generate a compressed stream using NZipLib
27            stream = CompressionHelper.getCompressedStreamCopy(stream);
28
29            // push onto stack and forward the request
30            sinkStack.Push(this,null);
31            _nextSink.AsyncProcessRequest(sinkStack,msg,headers,stream);
32        }
33
34
35        public void AsyncProcessResponse(IClientResponseChannelSinkStack sinkStack, 
36                                            object state, 
37                                            ITransportHeaders headers, 
38                                            Stream stream) 
39        {
40
41            // deflate the response
42            stream = 
43                CompressionHelper.getUncompressedStreamCopy(stream);
44
45            // forward the request
46            sinkStack.AsyncProcessResponse(headers,stream);
47        }
48
49
50        public Stream GetRequestStream(IMessage msg, 
51                                       ITransportHeaders headers) 
52        {
53            return _nextSink.GetRequestStream(msg, headers);
54        }
55
56
57        public void ProcessMessage(IMessage msg, 
58                                   ITransportHeaders requestHeaders, 
59                                   Stream requestStream, 
60                                   out ITransportHeaders responseHeaders, 
61                                   out Stream responseStream) 
62        {
63            // generate a compressed stream using NZipLib
64
65            Stream localrequestStream  = 
66                CompressionHelper.getCompressedStreamCopy(requestStream);
67
68            Stream localresponseStream;
69            // forward the call to the next sink
70            _nextSink.ProcessMessage(msg,
71                                     requestHeaders,
72                                     localrequestStream, 
73                                     out responseHeaders, 
74                                     out localresponseStream);
75
76            // deflate the response
77            responseStream = 
78                CompressionHelper.getUncompressedStreamCopy(localresponseStream);
79
80        }
81    }

 1 public   class  CompressionServerSinkProvider: IServerChannelSinkProvider
 2      {
 3        private IServerChannelSinkProvider _nextProvider;
 4
 5        public CompressionServerSinkProvider(IDictionary properties, ICollection providerData) 
 6        {
 7            // not yet needed
 8        }
 9
10        public IServerChannelSinkProvider Next
11        {
12            get {
13                return _nextProvider; 
14            }
15            set {
16                _nextProvider = value;
17            }
18        }
19
20        public IServerChannelSink CreateSink(IChannelReceiver channel)
21        {
22            // create other sinks in the chain
23            IServerChannelSink next = _nextProvider.CreateSink(channel);                
24    
25            // put our sink on top of the chain and return it                
26            return new CompressionServerSink(next);
27        }
28
29        public void GetChannelData(IChannelDataStore channelData)
30        {
31            // not yet needed
32        }
33
34    }

using  System;
using  System.Runtime.Remoting.Channels;
using  System.Runtime.Remoting.Messaging;
using  System.IO;

namespace  CompressionSink
{

    public class CompressionServerSink: BaseChannelSinkWithProperties,
        IServerChannelSink
    {

        private IServerChannelSink _nextSink;

        public CompressionServerSink(IServerChannelSink next) 
        {
            _nextSink = next;
        }

        public IServerChannelSink NextChannelSink 
        {
            get 
            {
                return _nextSink;
            }
        }

        public void AsyncProcessResponse(IServerResponseChannelSinkStack sinkStack, 
            object state, 
            IMessage msg, 
            ITransportHeaders headers, 
            Stream stream) 
        {
            // compressing the response
            stream=CompressionHelper.getCompressedStreamCopy(stream);

            // forwarding to the stack for further processing
            sinkStack.AsyncProcessResponse(msg,headers,stream);
        }

        public Stream GetResponseStream(IServerResponseChannelSinkStack sinkStack, 
            object state, 
            IMessage msg, 
            ITransportHeaders headers)
        {
            return null;
        }

        public ServerProcessing ProcessMessage(IServerChannelSinkStack sinkStack, 
            IMessage requestMsg, 
            ITransportHeaders requestHeaders,
            Stream requestStream, 
            out IMessage responseMsg, 
            out ITransportHeaders responseHeaders, 
            out Stream responseStream) 
        {
            // uncompressing the request
            Stream  localrequestStream = 
                CompressionHelper.getUncompressedStreamCopy(requestStream);

            // pushing onto stack and forwarding the call
            sinkStack.Push(this,null);

            Stream localresponseStream;
            ServerProcessing srvProc = _nextSink.ProcessMessage(sinkStack,
                requestMsg,
                requestHeaders,
                localrequestStream,
                out responseMsg,
                out responseHeaders,
                out localresponseStream);

            // compressing the response
            responseStream=
                CompressionHelper.getCompressedStreamCopy(localresponseStream);

            // returning status information
            return srvProc;
        }
    }
}

 1 public   class  CompressionHelper 
 2      {
 3
 4        /**//// <summary>
 5        /// refactor  by zendy
 6        /// </summary>
 7        /// <param name="inStream"></param>
 8        /// <returns></returns>
 9        public static Stream getCompressedStreamCopy(Stream inStream) 
10        {
11            MemoryStream outStream = new MemoryStream();
12            Deflater mDeflater = new Deflater(Deflater.BEST_COMPRESSION);
13            DeflaterOutputStream compressStream = new DeflaterOutputStream(outStream,mDeflater);
14
15            byte[] buf = new Byte[4096];
16            int cnt = inStream.Read(buf,0,4096);
17            while (cnt>0) {
18                compressStream.Write(buf,0,cnt);
19                cnt = inStream.Read(buf,0,4096);
20            }
21            compressStream.Finish();
22            //modify by zendy //这个设置非常重要,否则会导致后续Sink在处理该stream时失败,在原来的源码中就是因为没有这个处理导致程序运行失败
23            outStream.Seek(0,SeekOrigin.Begin);
24            return outStream;
25        }
26
27        /**//// <summary>
28        /// refactor  by zendy
29        /// </summary>
30        /// <param name="inStream"></param>
31        /// <returns></returns>
32        public static Stream getUncompressedStreamCopy(Stream inStream) 
33        {
34            InflaterInputStream unCompressStream = new InflaterInputStream(inStream); 
35            MemoryStream outStream = new MemoryStream();
36            int mSize;
37            Byte[] mWriteData = new Byte[4096];
38            while(true)
39            {
40                mSize = unCompressStream.Read(mWriteData, 0, mWriteData.Length);
41                if (mSize > 0)
42                {
43                    outStream.Write(mWriteData, 0, mSize);
44                }
45                else
46                {
47                    break;
48                }
49            }
50            unCompressStream.Close();
51            //modify by zendy//这个设置非常重要,否则会导致后续Sink在处理该stream时失败,,在原来的源码中就是因为没有这个处理导致程序运行失败
52            outStream.Seek(0,SeekOrigin.Begin);
53            return outStream;
54        }
55    }

BTW，这个Sink还可以扩展，比如判断需要压缩Stream的大小，如果很大，就压缩，否则不压缩（可以在responseHeaders和requestHeaders添加是否 已经压缩的标记)