Protocol Buffers(简称Protobuf)是一种语言中立、平台中立、可扩展的序列化数据结构的方式。它由Google开发,是一种类似于XML和JSON的数据交换格式,但具有更高的效率和灵活性。在本文中,我们将详细探讨Protocol Buffers 3的语法和使用方法。
Protocol Buffers是一种用于定义结构化数据的语言。它允许你定义数据结构,然后自动生成用于读写这些结构化数据的代码。与XML和JSON相比,Protobuf更加紧凑和高效,特别适合用于需要高性能和小数据量的场景,如网络通信和数据存储。
在使用Protocol Buffers之前,需要安装Protocol Buffers编译器protoc,以及相应语言的Protobuf库。以下是安装步骤:
bash
# 安装Protocol Buffers编译器
brew install protobuf
powershell
winget install protobuf --verbose
Found protobuf [Google.Protobuf] Version 27.1
This application is licensed to you by its owner.
Microsoft is not responsible for, nor does it grant any licenses to, third-party packages.
Downloading https://github.com/protocolbuffers/protobuf/releases/download/v27.1/protoc-27.1-win64.zip
██████████████████████████████ 3.08 MB / 3.08 MB
Successfully verified installer hash
Extracting archive...
Successfully extracted archive
Starting package install...
Command line alias added: "protoc"
Successfully installed
protoc --version
libprotoc 27.1
bash
# 安装Protobuf Python库
pip install protobuf
一个Protocol Buffers文件以.proto为扩展名。以下是一个简单的.proto文件示例:
protobuf
syntax = "proto3";
message Person {
string name = 1;
int32 id = 2;
string email = 3;
}
syntax = "proto3";
:指定语法版本为proto3。message
:用于定义一个消息类型。string
、int32
。1
、2
、3
。Protocol Buffers支持多种基本类型:
int32
、int64
、uint32
、uint64
、sint32
、sint64
、fixed32
、fixed64
、sfixed32
、sfixed64
。float
、double
。bool
。string
。bytes
。枚举用于定义一组命名常量。
protobuf
enum PhoneType {
MOBILE = 0;
HOME = 1;
WORK = 2;
}
首先,我们定义一个复杂的.proto文件,包含嵌套消息和枚举:
protobuf
syntax = "proto3";
message Person {
string name = 1;
int32 id = 2;
string email = 3;
repeated PhoneNumber phones = 4;
message PhoneNumber {
string number = 1;
PhoneType type = 2;
}
enum PhoneType {
MOBILE = 0;
HOME = 1;
WORK = 2;
}
}
使用protoc编译器生成对应语言的代码:
bash
protoc --python_out=. person.proto
生成的代码示例:
python
# -*- coding: utf-8 -*-
# Generated by the protocol buffer compiler. DO NOT EDIT!
# NO CHECKED-IN PROTOBUF GENCODE
# source: person.proto
# Protobuf Python Version: 5.27.1
"""Generated protocol buffer code."""
from google.protobuf import descriptor as _descriptor
from google.protobuf import descriptor_pool as _descriptor_pool
from google.protobuf import runtime_version as _runtime_version
from google.protobuf import symbol_database as _symbol_database
from google.protobuf.internal import builder as _builder
_runtime_version.ValidateProtobufRuntimeVersion(
_runtime_version.Domain.PUBLIC,
5,
27,
1,
'',
'person.proto'
)
# @@protoc_insertion_point(imports)
_sym_db = _symbol_database.Default()
DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(b'\n\x0cperson.proto\"\xc3\x01\n\x06Person\x12\x0c\n\x04name\x18\x01 \x01(\t\x12\n\n\x02id\x18\x02 \x01(\x05\x12\r\n\x05\x65mail\x18\x03 \x01(\t\x12#\n\x06phones\x18\x04 \x03(\x0b\x32\x13.Person.PhoneNumber\x1a>\n\x0bPhoneNumber\x12\x0e\n\x06number\x18\x01 \x01(\t\x12\x1f\n\x04type\x18\x02 \x01(\x0e\x32\x11.Person.PhoneType\"+\n\tPhoneType\x12\n\n\x06MOBILE\x10\x00\x12\x08\n\x04HOME\x10\x01\x12\x08\n\x04WORK\x10\x02\x62\x06proto3')
_globals = globals()
_builder.BuildMessageAndEnumDescriptors(DESCRIPTOR, _globals)
_builder.BuildTopDescriptorsAndMessages(DESCRIPTOR, 'person_pb2', _globals)
if not _descriptor._USE_C_DESCRIPTORS:
DESCRIPTOR._loaded_options = None
_globals['_PERSON']._serialized_start=17
_globals['_PERSON']._serialized_end=212
_globals['_PERSON_PHONENUMBER']._serialized_start=105
_globals['_PERSON_PHONENUMBER']._serialized_end=167
_globals['_PERSON_PHONETYPE']._serialized_start=169
_globals['_PERSON_PHONETYPE']._serialized_end=212
# @@protoc_insertion_point(module_scope)
生成的Python代码可以用于序列化和反序列化数据。
python
import person_pb2
# 创建一个Person对象
person = person_pb2.Person()
person.id = 1234
person.name = "John Doe"
person.email = "johndoe@example.com"
# 添加电话号码
phone = person.phones.add()
phone.number = "123-456-7890"
phone.type = person_pb2.Person.MOBILE
# 序列化为二进制数据
data = person.SerializeToString()
# 反序列化
person2 = person_pb2.Person()
person2.ParseFromString(data)
print(person2)
Protocol Buffers 3是一种强大且高效的数据序列化工具,适用于多种应用场景。在这里我们介绍了Protocol Buffers 3的基本语法和使用方法,希望能帮助大家更好地理解和使用Protobuf。在实际项目中,合理使用Protobuf可以显著提高数据传输和存储的效率。