C#中使用Google.Protobuf工具的操作小结

　protobuf是一个语言无关、平台无关的序列化协议，由谷歌开源提供。再加上其高性能、存储占用更小等特点，在云原生的应用中越来越广泛。

在C#中主要有两种方法来使用protobuf协议，nuget包分别为Google.Protobuf和protobuf-net，其中Google.Protobuf由谷歌官方提供。本文简要记录和展示Google.Protobuf的使用方法和特点。

项目资料及文档

• 项目官网：https://developers.google.cn/protocol-buffers?hl=zh-cn
• github主页：https://github.com/protocolbuffers/protobuf/
• 官方文档：https://developers.google.cn/protocol-buffers/docs/overview?hl=zh-cn
• 该nuget包支持.NETFramework 4.5、.NETStandard1.1、.net5等

准备工作

　　需要用到的nuget有如下两个：Google.Protobuf、Google.Protobuf.Tools，其中Google.Protobuf是主类库，运行时要用到。Google.Protobuf.Tools提供了命令行工具，用于根据.proto文件转为目标语言的类型，仅开发时使用，运行时不需要。

　　本次Demo使用的.proto文件内容如下：

syntax = "proto3";
option cc_enable_arenas = true;

package Tccc.Demo.Protobuf;

message ErrorLog {
    string LogID = 1;
    string Context = 2;
    string Stack = 3;
}

　　首先需要根据.proto文件生成目标类型，操作如下：

./google.protobuf.tools\3.19.1\tools\windows_x64\protoc.exe --csharp_out=./generatedCode ./proto/ErrorLog.proto

　　其中--csharp_out选项是生成C#语言的目标类型，运行protoc.exe -h 查看帮助信息，可以看到还支持一下几种选项： 

--proto_path=PATH

--cpp_out=OUT_DIR Generate C++ header and source.

--csharp_out=OUT_DIR Generate C# source file.

--java_out=OUT_DIR Generate Java source file.

--js_out=OUT_DIR Generate JavaScript source.

--kotlin_out=OUT_DIR Generate Kotlin file.

--objc_out=OUT_DIR Generate Objective-C header and source.

--php_out=OUT_DIR Generate PHP source file.

--python_out=OUT_DIR Generate Python source file.

--ruby_out=OUT_DIR Generate Ruby source file.

　　运行上述命令，会根据指定的ErrorLog.proto文件生成ErrorLog.cs文件，文件中就是C#类型ErrorLog。生成的代码中会给此类型增加方法void WriteTo(CodedOutputStream output)和只读属性Parser，接下来进行序列化和反序列化的关键。

生成的ErrorLog类的完整代码：

// 
//     Generated by the protocol buffer compiler.  DO NOT EDIT!
//     source: ProtoFiles/ErrorLog.proto
// 
#pragma warning disable 1591, 0612, 3021
#region Designer generated code

using pb = global::Google.Protobuf;
using pbc = global::Google.Protobuf.Collections;
using pbr = global::Google.Protobuf.Reflection;
using scg = global::System.Collections.Generic;
namespace Tccc.Demo.Protobuf {

  /// 
Holder for reflection information generated from ProtoFiles/ErrorLog.proto
  public static partial class ErrorLogReflection {

    #region Descriptor
    /// 
File descriptor for ProtoFiles/ErrorLog.proto
    public static pbr::FileDescriptor Descriptor {
      get { return descriptor; }
    }
    private static pbr::FileDescriptor descriptor;

    static ErrorLogReflection() {
      byte[] descriptorData = global::System.Convert.FromBase64String(
          string.Concat(
            "ChlQcm90b0ZpbGVzL0Vycm9yTG9nLnByb3RvEhJUY2NjLkRlbW8uUHJvdG9i",
            "dWYiOQoIRXJyb3JMb2cSDQoFTG9nSUQYASABKAkSDwoHQ29udGV4dBgCIAEo",
            "CRINCgVTdGFjaxgDIAEoCUID+AEBYgZwcm90bzM="));
      descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
          new pbr::FileDescriptor[] { },
          new pbr::GeneratedClrTypeInfo(null, null, new pbr::GeneratedClrTypeInfo[] {
            new pbr::GeneratedClrTypeInfo(typeof(global::Tccc.Demo.Protobuf.ErrorLog), global::Tccc.Demo.Protobuf.ErrorLog.Parser, new[]{ "LogID", "Context", "Stack" }, null, null, null, null)
          }));
    }
    #endregion

  }
  #region Messages
  public sealed partial class ErrorLog : pb::IMessage
  #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
      , pb::IBufferMessage
  #endif
  {
    private static readonly pb::MessageParser _parser = new pb::MessageParser(() => new ErrorLog());
    private pb::UnknownFieldSet _unknownFields;
    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public static pb::MessageParser Parser { get { return _parser; } }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public static pbr::MessageDescriptor Descriptor {
      get { return global::Tccc.Demo.Protobuf.ErrorLogReflection.Descriptor.MessageTypes[0]; }
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    pbr::MessageDescriptor pb::IMessage.Descriptor {
      get { return Descriptor; }
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public ErrorLog() {
      OnConstruction();
    }

    partial void OnConstruction();

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public ErrorLog(ErrorLog other) : this() {
      logID_ = other.logID_;
      context_ = other.context_;
      stack_ = other.stack_;
      _unknownFields = pb::UnknownFieldSet.Clone(other._unknownFields);
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public ErrorLog Clone() {
      return new ErrorLog(this);
    }

    /// 
Field number for the "LogID" field.
    public const int LogIDFieldNumber = 1;
    private string logID_ = "";
    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public string LogID {
      get { return logID_; }
      set {
        logID_ = pb::ProtoPreconditions.CheckNotNull(value, "value");
      }
    }

    /// 
Field number for the "Context" field.
    public const int ContextFieldNumber = 2;
    private string context_ = "";
    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public string Context {
      get { return context_; }
      set {
        context_ = pb::ProtoPreconditions.CheckNotNull(value, "value");
      }
    }

    /// 
Field number for the "Stack" field.
    public const int StackFieldNumber = 3;
    private string stack_ = "";
    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public string Stack {
      get { return stack_; }
      set {
        stack_ = pb::ProtoPreconditions.CheckNotNull(value, "value");
      }
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public override bool Equals(object other) {
      return Equals(other as ErrorLog);
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public bool Equals(ErrorLog other) {
      if (ReferenceEquals(other, null)) {
        return false;
      }
      if (ReferenceEquals(other, this)) {
        return true;
      }
      if (LogID != other.LogID) return false;
      if (Context != other.Context) return false;
      if (Stack != other.Stack) return false;
      return Equals(_unknownFields, other._unknownFields);
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public override int GetHashCode() {
      int hash = 1;
      if (LogID.Length != 0) hash ^= LogID.GetHashCode();
      if (Context.Length != 0) hash ^= Context.GetHashCode();
      if (Stack.Length != 0) hash ^= Stack.GetHashCode();
      if (_unknownFields != null) {
        hash ^= _unknownFields.GetHashCode();
      }
      return hash;
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public override string ToString() {
      return pb::JsonFormatter.ToDiagnosticString(this);
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public void WriteTo(pb::CodedOutputStream output) {
    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
      output.WriteRawMessage(this);
    #else
      if (LogID.Length != 0) {
        output.WriteRawTag(10);
        output.WriteString(LogID);
      }
      if (Context.Length != 0) {
        output.WriteRawTag(18);
        output.WriteString(Context);
      }
      if (Stack.Length != 0) {
        output.WriteRawTag(26);
        output.WriteString(Stack);
      }
      if (_unknownFields != null) {
        _unknownFields.WriteTo(output);
      }
    #endif
    }

    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    void pb::IBufferMessage.InternalWriteTo(ref pb::WriteContext output) {
      if (LogID.Length != 0) {
        output.WriteRawTag(10);
        output.WriteString(LogID);
      }
      if (Context.Length != 0) {
        output.WriteRawTag(18);
        output.WriteString(Context);
      }
      if (Stack.Length != 0) {
        output.WriteRawTag(26);
        output.WriteString(Stack);
      }
      if (_unknownFields != null) {
        _unknownFields.WriteTo(ref output);
      }
    }
    #endif

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public int CalculateSize() {
      int size = 0;
      if (LogID.Length != 0) {
        size += 1 + pb::CodedOutputStream.ComputeStringSize(LogID);
      }
      if (Context.Length != 0) {
        size += 1 + pb::CodedOutputStream.ComputeStringSize(Context);
      }
      if (Stack.Length != 0) {
        size += 1 + pb::CodedOutputStream.ComputeStringSize(Stack);
      }
      if (_unknownFields != null) {
        size += _unknownFields.CalculateSize();
      }
      return size;
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public void MergeFrom(ErrorLog other) {
      if (other == null) {
        return;
      }
      if (other.LogID.Length != 0) {
        LogID = other.LogID;
      }
      if (other.Context.Length != 0) {
        Context = other.Context;
      }
      if (other.Stack.Length != 0) {
        Stack = other.Stack;
      }
      _unknownFields = pb::UnknownFieldSet.MergeFrom(_unknownFields, other._unknownFields);
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    public void MergeFrom(pb::CodedInputStream input) {
    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
      input.ReadRawMessage(this);
    #else
      uint tag;
      while ((tag = input.ReadTag()) != 0) {
        switch(tag) {
          default:
            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, input);
            break;
          case 10: {
            LogID = input.ReadString();
            break;
          }
          case 18: {
            Context = input.ReadString();
            break;
          }
          case 26: {
            Stack = input.ReadString();
            break;
          }
        }
      }
    #endif
    }

    #if !GOOGLE_PROTOBUF_REFSTRUCT_COMPATIBILITY_MODE
    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    [global::System.CodeDom.Compiler.GeneratedCode("protoc", null)]
    void pb::IBufferMessage.InternalMergeFrom(ref pb::ParseContext input) {
      uint tag;
      while ((tag = input.ReadTag()) != 0) {
        switch(tag) {
          default:
            _unknownFields = pb::UnknownFieldSet.MergeFieldFrom(_unknownFields, ref input);
            break;
          case 10: {
            LogID = input.ReadString();
            break;
          }
          case 18: {
            Context = input.ReadString();
            break;
          }
          case 26: {
            Stack = input.ReadString();
            break;
          }
        }
      }
    }
    #endif

  }

  #endregion

}

#endregion Designer generated code

序列化操作

        public static byte[] Serialize(ErrorLog log)
        {
            using (MemoryStream output = new MemoryStream())
            {
                log.WriteTo(output);
                return output.ToArray();
            }
        }

反序列化操作     

   ErrorLog desErrorLog= ErrorLog.Parser.ParseFrom(data);

使用特点和理解

protoc.exe是支持生成多语言类型，这对于跨语言的混合编程比较方便。

根据上述使用步骤可以看到，必须先使用工具protoc生成目标类型，才能调用序列化和反序列化方法，这有些不符合.net平台的编码习惯。

一堆自动生成的C#类在可维护性方面欠佳，当需要调整属性字段时，还要通过工具重新生成，较为麻烦。

到此这篇关于C#中使用Google.Protobuf工具的的文章就介绍到这了,更多相关C#使用Google.Protobuf工具内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！