项目中使用protobuf 3.0

Posted 2020-09-14 小砖整理

protocol buffer从3.0 原生的compiler支持c++,Java,Python,Go,Ruby,JavaNano,javascript,Objective-C,C#,php这篇文章作为上一篇文章的补充，简单记录下一些变化。

protobuf的开源地址为：https://github.com/google/protobuf

protocol compiler下载地址为：https://github.com/google/protobuf/releases

官方定义message类型的例子：

syntax="proto3"

message SearchRequest{

　　string query=1;

　　int32 page_number=2;

　　int32 result_per_page=3;

}

..proto文件的第一行指定使用proto3的语法。

 

特定语言的声明使用option关键定和选项名

option java_package="com.example.tutorial";//定义生成的java包

option java_outer_classname="AddressBookProtos";//定义java类名

option csharp_namespace="Google.Protobuf.Examples.AddressBook";//定义c#的命名空间

 

变化

1.字段前取消了required和optional两个关键字，目前可用的只有repeated关键字。

2.不可以现设置默认值了。

　　a.string默认为空串

　　b.枚举默认为第一个枚举定义的第一个值。并且必须是0

　　c.bytes默认为空bytes

　　d.bool默认为false

　　e.数字类型默认为0

 

3.类型对应表

.proto Type	Notes	C++ Type	Java Type	Python Type[2]	Go Type	Ruby Type	C# Type	PHP Type
double		double	double	float	float64	Float	double	float
float		float	float	float	float32	Float	float	float
int32	Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint32 instead.	int32	int	int	int32	Fixnum or Bignum (as required)	int	integer
int64	Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint64 instead.	int64	long	int/long[3]	int64	Bignum	long	integer/string[5]
uint32	Uses variable-length encoding.	uint32	int[1]	int/long[3]	uint32	Fixnum or Bignum (as required)	uint	integer
uint64	Uses variable-length encoding.	uint64	long[1]	int/long[3]	uint64	Bignum	ulong	integer/string[5]
sint32	Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int32s.	int32	int	int	int32	Fixnum or Bignum (as required)	int	integer
sint64	Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int64s.	int64	long	int/long[3]	int64	Bignum	long	integer/string[5]
fixed32	Always four bytes. More efficient than uint32 if values are often greater than 228.	uint32	int[1]	int	uint32	Fixnum or Bignum (as required)	uint	integer
fixed64	Always eight bytes. More efficient than uint64 if values are often greater than 256.	uint64	long[1]	int/long[3]	uint64	Bignum	ulong	integer/string[5]
sfixed32	Always four bytes.	int32	int	int	int32	Fixnum or Bignum (as required)	int	integer
sfixed64	Always eight bytes.	int64	long	int/long[3]	int64	Bignum	long	integer/string[5]
bool		bool	boolean	bool	bool	TrueClass/FalseClass	bool	boolean
string	A string must always contain UTF-8 encoded or 7-bit ASCII text.	string	String	str/unicode[4]	string	String (UTF-8)	string	string
bytes	May contain any arbitrary sequence of bytes.	string	ByteString	str	[]byte	String (ASCII-8BIT)	ByteString	string

 

proto代码编译

语法：

protoc --proto_path=IMPORT_PATH --cpp_out=DST_DIR --java_out=DST_DIR --python_out=DST_DIR --go_out=DST_DIR --ruby_out=DST_DIR --javanano_out=DST_DIR --objc_out=DST_DIR --csharp_out=DST_DIR path/to/file.proto

--proto_path 当proto文件中使用import时指定的导入文件的位置

--cpp_out c++输出目录

--java_out java输出目录

--python_out

--go_out

--ruby_out ruby输出目录

--objc_out oc输出目录

--csharp_out c#输出目录

path/to/file.proto为要编译的proto文件

使用

proto内容：

syntax="proto3";

option java_package="com.ztimage";
option java_outer_classname="WebUI";
option csharp_namespace="ZTImage.WebUI";
message SearchRequest{
string query=1;
int32 page_number=2;
int32 result_per_page=3;
}

 

执行命令：protoc --csharp_out d:/programs/protoc/bin WebUI.proto

生成代码：

// Generated by the protocol buffer compiler.  DO NOT EDIT!
// source: WebUI.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 ZTImage.WebUI {

  /// <summary>Holder for reflection information generated from WebUI.proto</summary>
  public static partial class WebUIReflection {

    #region Descriptor
    /// <summary>File descriptor for WebUI.proto</summary>
    public static pbr::FileDescriptor Descriptor {
      get { return descriptor; }
    }
    private static pbr::FileDescriptor descriptor;

    static WebUIReflection() {
      byte[] descriptorData = global::System.Convert.FromBase64String(
          string.Concat(
            "CgtXZWJVSS5wcm90byJMCg1TZWFyY2hSZXF1ZXN0Eg0KBXF1ZXJ5GAEgASgJ",
            "EhMKC3BhZ2VfbnVtYmVyGAIgASgFEhcKD3Jlc3VsdF9wZXJfcGFnZRgDIAEo",
            "BUIkCgtjb20uenRpbWFnZUIFV2ViVUmqAg1aVEltYWdlLldlYlVJYgZwcm90",
            "bzM="));
      descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
          new pbr::FileDescriptor[] { },
          new pbr::GeneratedClrTypeInfo(null, new pbr::GeneratedClrTypeInfo[] {
            new pbr::GeneratedClrTypeInfo(typeof(global::ZTImage.WebUI.SearchRequest), global::ZTImage.WebUI.SearchRequest.Parser, new[]{ "Query", "PageNumber", "ResultPerPage" }, null, null, null)
          }));
    }
    #endregion

  }
  #region Messages
  public sealed partial class SearchRequest : pb::IMessage<SearchRequest> {
    private static readonly pb::MessageParser<SearchRequest> _parser = new pb::MessageParser<SearchRequest>(() => new SearchRequest());
    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public static pb::MessageParser<SearchRequest> Parser { get { return _parser; } }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public static pbr::MessageDescriptor Descriptor {
      get { return global::ZTImage.WebUI.WebUIReflection.Descriptor.MessageTypes[0]; }
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    pbr::MessageDescriptor pb::IMessage.Descriptor {
      get { return Descriptor; }
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public SearchRequest() {
      OnConstruction();
    }

    partial void OnConstruction();

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public SearchRequest(SearchRequest other) : this() {
      query_ = other.query_;
      pageNumber_ = other.pageNumber_;
      resultPerPage_ = other.resultPerPage_;
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public SearchRequest Clone() {
      return new SearchRequest(this);
    }

    /// <summary>Field number for the "query" field.</summary>
    public const int QueryFieldNumber = 1;
    private string query_ = "";
    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public string Query {
      get { return query_; }
      set {
        query_ = pb::ProtoPreconditions.CheckNotNull(value, "value");
      }
    }

    /// <summary>Field number for the "page_number" field.</summary>
    public const int PageNumberFieldNumber = 2;
    private int pageNumber_;
    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public int PageNumber {
      get { return pageNumber_; }
      set {
        pageNumber_ = value;
      }
    }

    /// <summary>Field number for the "result_per_page" field.</summary>
    public const int ResultPerPageFieldNumber = 3;
    private int resultPerPage_;
    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public int ResultPerPage {
      get { return resultPerPage_; }
      set {
        resultPerPage_ = value;
      }
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public override bool Equals(object other) {
      return Equals(other as SearchRequest);
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public bool Equals(SearchRequest other) {
      if (ReferenceEquals(other, null)) {
        return false;
      }
      if (ReferenceEquals(other, this)) {
        return true;
      }
      if (Query != other.Query) return false;
      if (PageNumber != other.PageNumber) return false;
      if (ResultPerPage != other.ResultPerPage) return false;
      return true;
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public override int GetHashCode() {
      int hash = 1;
      if (Query.Length != 0) hash ^= Query.GetHashCode();
      if (PageNumber != 0) hash ^= PageNumber.GetHashCode();
      if (ResultPerPage != 0) hash ^= ResultPerPage.GetHashCode();
      return hash;
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public override string ToString() {
      return pb::JsonFormatter.ToDiagnosticString(this);
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public void WriteTo(pb::CodedOutputStream output) {
      if (Query.Length != 0) {
        output.WriteRawTag(10);
        output.WriteString(Query);
      }
      if (PageNumber != 0) {
        output.WriteRawTag(16);
        output.WriteInt32(PageNumber);
      }
      if (ResultPerPage != 0) {
        output.WriteRawTag(24);
        output.WriteInt32(ResultPerPage);
      }
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public int CalculateSize() {
      int size = 0;
      if (Query.Length != 0) {
        size += 1 + pb::CodedOutputStream.ComputeStringSize(Query);
      }
      if (PageNumber != 0) {
        size += 1 + pb::CodedOutputStream.ComputeInt32Size(PageNumber);
      }
      if (ResultPerPage != 0) {
        size += 1 + pb::CodedOutputStream.ComputeInt32Size(ResultPerPage);
      }
      return size;
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public void MergeFrom(SearchRequest other) {
      if (other == null) {
        return;
      }
      if (other.Query.Length != 0) {
        Query = other.Query;
      }
      if (other.PageNumber != 0) {
        PageNumber = other.PageNumber;
      }
      if (other.ResultPerPage != 0) {
        ResultPerPage = other.ResultPerPage;
      }
    }

    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
    public void MergeFrom(pb::CodedInputStream input) {
      uint tag;
      while ((tag = input.ReadTag()) != 0) {
        switch(tag) {
          default:
            input.SkipLastField();
            break;
          case 10: {
            Query = input.ReadString();
            break;
          }
          case 16: {
            PageNumber = input.ReadInt32();
            break;
          }
          case 24: {
            ResultPerPage = input.ReadInt32();
            break;
          }
        }
      }
    }

  }

  #endregion

}

#endregion Designer generated code

View Code

在项目中引用Google.Protobuf程序集，生成的代码放到项目中

测试代码：

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Google.Protobuf;

namespace ZTImage.WebUI
{
    class Program
    {
        static void Main(string[] args)
        {
            SearchRequest request = new SearchRequest() {
                Query="age>0 and age <18",
                PageNumber=1,
                ResultPerPage=50
            };

            using (var output = File.Create("mr.dat"))
            {
                request.WriteTo(output);
            }



            SearchRequest sr = null;
            using (var input = File.OpenRead("mr.dat"))
            {
                sr = SearchRequest.Parser.ParseFrom(input);
            }

            Console.WriteLine("Query:{0},PageNumber:{1},ResultPerPage:{2}",sr.Query,sr.PageNumber,sr.ResultPerPage);
            Console.ReadKey();
                

            
            
        }
    }
}

View Code

结果：

Query:age>0 and age <18,PageNumber:1,ResultPerPage:50

pref:

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