Google.ProtocolBuffers.dll 之.Net应用（一）

原创文章，转载必需注明出处：http://www.cnblogs.com/wu-jian/

http://www.cnblogs.com/wu-jian/archive/2011/02/22/1961104.html

核心提示：Google Protocol Buffers是google出品的一个协议生成工具，特点就是跨平台，Google Protocol Buffers 快速入门（带生成C#源码的方法），效率高，速度快，只有 AddressBookProtos.cs有用，将这个文件连同Google.ProtocolBuffers.dll一起.

前言

最近接到一个跨平台的测试项目，服务端Linux，是Java开发的一系列Socket接口，客户端Windows，所以准备用.Net。本想这种跨主流平台的Socket通信应该不成问题，但随着代码进程，随着一次次反复调试，我发现我错了。花了一周时间至今两者仍呈现北方网通和南方电信的姿态。

不过总有意外惊喜，过程中认识了Protocol Buffer，比XML、比JSON更为强悍，语言无关、平台无关、更小的存储、更少的歧义、更高的性能，其实Google一直在贡献，不论是Copy Left的还是Copy Right的，回头看看我们的百度，抄IM抄商城抄游戏抄视频抄房地产，还有搜索永远排第一却打不开的百度文库，印象中JQuery盛行N久之后百度开源了一个JS库，记忆里这也是百度为中国互联网技术做的唯一贡献，大公司的责任呐，好了，再说就偏离主题了。

Protocal Buffer官方站点：http://code.google.com/p/protobuf/ ，遗憾的是不支持.Net，但社区的力量不容忽视，MySQL最近还推出社区版呢，从这个链接可以看到Protobuf的社区阵营：http://code.google.com/p/protobuf/wiki/ThirdPartyAddOns

OK，本文主要描述自己在.Net中基于应用层面使用Protobuf的一些体会，作为学习笔记与大家分享，个人能力有限，不足之处还请及时指正。

需求

Java为服务端，.Net为客户端，Socket通信，使用Protobuf进行数据封装和传输，如下图：

DEMO中构造了3个简单的.proto文件供各客户端使用：

message MyRequest {
//版本号
required int32 version =1;
//姓名
required string name =2;
//个人网站
optional string website =3[default="http://www.paotiao.com/"];
//附加数据
optional bytes data =4;
}

message MyResponse {
//版本号
required int32 version =1;
//响应结果
required int32 result =2;
}

message MyData {
//个人简介
optional string resume =1[default="I'm goodman"];
}

其中MyRequest为客户端的请求，MyResponse为服务端的响应，MyData作为一个属性附加在MyRequest的data字段中，提醒注意这个byte类型的data字段，为此花费了最多时间并最终导至放弃Protobuf-net来做跨平台的应用。

Protobuf-net

官方站点：http://code.google.com/p/protobuf-net/

Protobuf-net是第三方中最强大应用最广泛的一个，支持.Net、C#、WCF、VB，并且DEMO丰富，网上可查到的资料也最多。

生成.CS类文件

安装后通过 protogen.exe 就可将.proto文件生成.cs文件(Demo中我将命令封装在/tools/getCS.bat中)：

echo on
protogen -i:ProtoMyRequest.proto -o:ProtoMyRequest.cs
protogen -i:ProtoMyResponse.proto -o:ProtoMyResponse.cs
protogen -i:ProtoMyData.proto -o:ProtoMyData.cs

接着将生成的3个.cs文件包含在项目中，同时在项目中引用protobuf-net.dll

代码示例(服务端与客户端)

using System;
using System.IO;
using System.Text;
using System.Threading;
using System.Net;
using System.Net.Sockets;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;
using ProtoBuf;
//自定义
using ProtoMyData;
using ProtoMyRequest;
using ProtoMyResponse;
 
namespace protobuf_net
{
    class Program
    {
        private static ManualResetEvent allDone = new ManualResetEvent(false);
 
        static void Main(string[] args)
        {
            beginDemo();
        }
 
        private static void beginDemo()
        {
            //启动服务端
            TcpListener server = new TcpListener(IPAddress.Parse("127.0.0.1"), 9527);
            server.Start();
            server.BeginAcceptTcpClient(clientConnected, server);
            Console.WriteLine("SERVER : 等待数据 ---");
 
            //启动客户端
            ThreadPool.QueueUserWorkItem(runClient);
            allDone.WaitOne();
 
            Console.WriteLine("SERVER : 退出 ---");
            server.Stop();
        }
 
        //服务端处理
        private static void clientConnected(IAsyncResult result)
        {
            try
            {
                TcpListener server = (TcpListener)result.AsyncState;
                using (TcpClient client = server.EndAcceptTcpClient(result))
                using (NetworkStream stream = client.GetStream())
                {
                    //获取
                    Console.WriteLine("SERVER : 客户端已连接，读取数据 ---");
                    //proto-buf 使用 Base128 Varints 编码
                    MyRequest myRequest = Serializer.DeserializeWithLengthPrefix<MyRequest>(stream, PrefixStyle.Base128);
 
                    //使用C# BinaryFormatter
                    IFormatter formatter = new BinaryFormatter();
                    MyData myData = (MyData)formatter.Deserialize(new MemoryStream(myRequest.data));
                    //MyData.MyData mydata = Serializer.DeserializeWithLengthPrefix<MyData.MyData>(new MemoryStream(request.data), PrefixStyle.Base128);
 
                    Console.WriteLine("SERVER : 获取成功, myRequest.version={0}, myRequest.name={1}, myRequest.website={2}, myData.resume={3}", myRequest.version, myRequest.name, myRequest.website, myData.resume);
 
                    //响应(MyResponse)
                    MyResponse myResponse = new MyResponse();
                    myResponse.version = myRequest.version;
                    myResponse.result = 99;
                    Serializer.SerializeWithLengthPrefix(stream, myResponse, PrefixStyle.Base128);
                    Console.WriteLine("SERVER : 响应成功 ---");
 
                    //DEBUG
                    //int final = stream.ReadByte();
                    //if (final == 123)
                    //{
                    //    Console.WriteLine("SERVER: Got client-happy marker");
                    //}
                    //else
                    //{
                    //    Console.WriteLine("SERVER: OOPS! Something went wrong");
                    //}
                    Console.WriteLine("SERVER: 关闭连接 ---");
                    stream.Close();
                    client.Close();
                }
            }
            finally
            {
                allDone.Set();
            }
        }
 
        //客户端请求
        private static void runClient(object state)
        {
            try
            {
                //构造MyData
                MyData myData = new MyData();
                myData.resume = "我的个人简介";
 
                //构造MyRequest
                MyRequest myRequest = new MyRequest();
                myRequest.version = 1;
                myRequest.name = "吴剑";
                myRequest.website = "www.paotiao.com";
 
                //使用C# BinaryFormatter
                using (MemoryStream ms = new MemoryStream())
                {
                    IFormatter formatter = new BinaryFormatter();
                    formatter.Serialize(ms, myData);
                    //Serializer.Serialize(ms, mydata);
                    myRequest.data = ms.GetBuffer();
                    ms.Close();
                }
                Console.WriteLine("CLIENT : 对象构造完毕 ...");
 
                using (TcpClient client = new TcpClient())
                {
                    client.Connect(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9527));
                    Console.WriteLine("CLIENT : socket 连接成功 ...");
 
                    using (NetworkStream stream = client.GetStream())
                    {
                        //发送
                        Console.WriteLine("CLIENT : 发送数据 ...");
                        ProtoBuf.Serializer.SerializeWithLengthPrefix(stream, myRequest, PrefixStyle.Base128);
 
                        //接收
                        Console.WriteLine("CLIENT : 等待响应 ...");
                        MyResponse myResponse = ProtoBuf.Serializer.DeserializeWithLengthPrefix<MyResponse>(stream, PrefixStyle.Base128);
 
                        Console.WriteLine("CLIENT : 成功获取结果, version={0}, result={1}", myResponse.version, myResponse.result);
 
                        //DEBUG client-happy marker
                        //stream.WriteByte(123);
 
                        //关闭
                        stream.Close();
                    }
                    client.Close();
                    Console.WriteLine("CLIENT : 关闭 ...");
                }
            }
            catch (Exception error)
            {
                Console.WriteLine("CLIENT ERROR : {0}", error.ToString());
            }
        }
 
    }//end class
}

从代码中可以发现protobuf-net已考虑的非常周到，不论是客户端发送对象还是服务端接收对象，均只需一行代码就可实现：

//客户端发送对象
ProtoBuf.Serializer.SerializeWithLengthPrefix(stream, myRequest, PrefixStyle.Base128);
//服务端接收对象
MyRequest myRequest = Serializer.DeserializeWithLengthPrefix<MyRequest>(stream, PrefixStyle.Base128);

所以如果Server与Client均使用.Net，Protobuf-net会是理想选择。

但我的项目需要跨平台，同时项目中又恰恰使用了byte类型字段，经过反复调试比较，发现一个关键问题：假使proto脚本和对象属性值完全一样，但只要包含byte类型的字段，那么通过Java序列化的二进制与C#序列化的二进制结果一定不同。而Protobuf中Google原生支持Java，那么几乎可以确定Protobuf-net对Protobuf的支持存在瑕疵。

后来在使用Protobuf-csharp-sport后验证了这一点，Protobuf-net使用C#的byte[]来实现bytes，而Java以及Protobuf-csharp-port均使用ByteString，前者是无符号的，后者是有符号的，语言的基本差异导致两者无法兼容，所以最终我只能放弃Protobuf-net。

Protobuf-csharp-port

官方站点：http://code.google.com/p/protobuf-csharp-port/

Protobuf-csharp-port的文档资料、DEMO、应用范围都不如Protobuf-net，但Protobuf-csharp-port更遵循Google的Protobuf，甚至应用和代码都几乎一样，所以跨平台，Protobuf-csharp-port是不二之选。

生成.CS类文件

先直接使用Google的 protoc.exe 生成二进制文件。

然后通过 protogen.exe 将二进制文件生成C#类文件(Demo中我将命令封装在/tools/getCS.bat中)：

echo on
protoc --descriptor_set_out=ProtoMyRequest.protobin --include_imports ProtoMyRequest.proto
protoc --descriptor_set_out=ProtoMyResponse.protobin --include_imports ProtoMyResponse.proto
protoc --descriptor_set_out=ProtoMyData.protobin --include_imports ProtoMyData.proto

protogen ProtoMyRequest.protobin
protogen ProtoMyResponse.protobin
protogen ProtoMyData.protobin

接着将生成的3个.cs文件包含在项目中，同时在项目中引用Google.ProtocolBuffers.dll

代码示例（服务端与客户端）

using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using Google.ProtocolBuffers;
 
namespace protobuf_csharp_sport
{
    class Program
    {
        private static ManualResetEvent allDone = new ManualResetEvent(false);
 
        static void Main(string[] args)
        {
            beginDemo();
        }
 
        private static void beginDemo()
        {
            //启动服务端
            TcpListener server = new TcpListener(IPAddress.Parse("127.0.0.1"), 9528);
            server.Start();
            server.BeginAcceptTcpClient(clientConnected, server);
            Console.WriteLine("SERVER : 等待数据 ---");
 
            //启动客户端
            ThreadPool.QueueUserWorkItem(runClient);
            allDone.WaitOne();
 
            Console.WriteLine("SERVER : 退出 ---");
            server.Stop();
        }
 
        //服务端处理
        private static void clientConnected(IAsyncResult result)
        {
            try
            {
                TcpListener server = (TcpListener)result.AsyncState;
                using (TcpClient client = server.EndAcceptTcpClient(result))
                {
                    using (NetworkStream stream = client.GetStream())
                    {
                        //获取
                        Console.WriteLine("SERVER : 客户端已连接，数据读取中 --- ");
                        byte[] myRequestBuffer = new byte[49];
                        int myRequestLength = 0;
                        do
                        {
                            myRequestLength = stream.Read(myRequestBuffer, 0, myRequestBuffer.Length);
                        }
                        while (stream.DataAvailable);
                        MyRequest myRequest = MyRequest.ParseFrom(myRequestBuffer);
                        MyData myData = MyData.ParseFrom(myRequest.Data);
                        Console.WriteLine("SERVER : 获取成功, myRequest.Version={0}, myRequest.Name={1}, myRequest.Website={2}, myData.Resume={3}", myRequest.Version, myRequest.Name, myRequest.Website, myData.Resume);
 
                        //响应(MyResponse)
                        MyResponse.Builder myResponseBuilder = MyResponse.CreateBuilder();
                        myResponseBuilder.Version = myRequest.Version;
                        myResponseBuilder.Result = 99;
                        MyResponse myResponse = myResponseBuilder.Build();
                        myResponse.WriteTo(stream);
                        Console.WriteLine("SERVER : 响应成功 ---");
 
                        Console.WriteLine("SERVER: 关闭连接 ---");
                        stream.Close();                        
                    }
                    client.Close();
                }
            }
            finally
            {
                allDone.Set();
            }
        }
 
        //客户端请求
        private static void runClient(object state)
        {
            try
            {
                //构造MyData
                MyData.Builder myDataBuilder = MyData.CreateBuilder();
                myDataBuilder.Resume = "我的个人简介";
                MyData myData = myDataBuilder.Build();
                 
                //构造MyRequest
                MyRequest.Builder myRequestBuilder = MyRequest.CreateBuilder();
                myRequestBuilder.Version = 1;
                myRequestBuilder.Name = "吴剑";
                myRequestBuilder.Website = "www.paotiao.com";
                //注：直接支持ByteString类型
                myRequestBuilder.Data = myData.ToByteString();
                MyRequest myRequest = myRequestBuilder.Build();
                                 
                Console.WriteLine("CLIENT : 对象构造完毕 ...");
 
                using (TcpClient client = new TcpClient())
                {
                    client.Connect(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9528));
                    Console.WriteLine("CLIENT : socket 连接成功 ...");
 
                    using (NetworkStream stream = client.GetStream())
                    {
                        //发送
                        Console.WriteLine("CLIENT : 发送数据 ...");
                        myRequest.WriteTo(stream);
 
                        //接收
                        Console.WriteLine("CLIENT : 等待响应 ...");
                        byte[] myResponseBuffer = new byte[4];
                        int myResponseLength = 0;
                        do
                        {
                            myResponseLength = stream.Read(myResponseBuffer, 0, myResponseBuffer.Length);
                        }
                        while (stream.DataAvailable);                        
                        MyResponse myResponse = MyResponse.ParseFrom(myResponseBuffer);
                        Console.WriteLine("CLIENT : 成功获取结果, myResponse.Version={0}, myResponse.Result={1}", myResponse.Version, myResponse.Result);
 
                        //关闭
                        stream.Close();
                    }
                    client.Close();
                    Console.WriteLine("CLIENT : 关闭 ...");
                }
            }
            catch (Exception error)
            {
                Console.WriteLine("CLIENT ERROR : {0}", error.ToString());
            }
        }
 
    }//end class
}

Protobuf#

官方站点：http://code.google.com/p/protosharp/

暂未测试Protobuf#

结束语

基本花了一周时间了解和学习了Google Protobuf在.NET下的应用，也找到了Protobuf跨平台的方案，但好事多魔，C# Socket发送的protobuf数据包在Java Netty 中怎么也获取不到，我想也许是平台差异，但对Java知之甚少，如有知情人士还请指点迷津。

DEMO

DEMO下载：http://files.cnblogs.com/wu-jian/ProtobufDemo.rar

DEMO运行环境：.Net Framework 4.0， VS2010

<全文完>

作者：吴剑
出处：http://www.cnblogs.com/wu-jian/
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