用Go快速上手Protocol Buffers详解

go install google.golang.org/protobuf/cmd/protoc-gen-go@latest

syntax = "proto3";
package tutorial;

import "google/protobuf/timestamp.proto";

// 生成代码的 import 路径；Go 包名取最后一段（这里是 tutorialpb）
option go_package = "github.com/protocolbuffers/protobuf/examples/go/tutorialpb";

message Person {
  string name = 1;
  int32  id   = 2;  // 唯一 ID
  string email = 3;

  message PhoneNumber {
    string number = 1;
    PhoneType type = 2;
  }

  repeated PhoneNumber phones = 4;
  google.protobuf.Timestamp last_updated = 5;
}

enum PhoneType {
  PHONE_TYPE_UNSPECIFIED = 0;
  PHONE_TYPE_MOBILE = 1;
  PHONE_TYPE_HOME = 2;
  PHONE_TYPE_WORK = 3;
}

message AddressBook {
  repeated Person people = 1;
}

protoc \
  -I=$SRC_DIR \
  --go_out=$DST_DIR \
  $SRC_DIR/addressbook.proto

import pb "github.com/protocolbuffers/protobuf/examples/go/tutorialpb"

p := pb.Person{
  Id:    1234,
  Name:  "John Doe",
  Email: "jdoe@example.com",
  Phones: []*pb.Person_PhoneNumber{
    {Number: "555-4321", Type: pb.PhoneType_PHONE_TYPE_HOME},
  },
}

import (
  "io/ioutil"
  "google.golang.org/protobuf/proto"
)

book := &pb.AddressBook{People: []*pb.Person{&p}}

out, err := proto.Marshal(book)
if err != nil { log.Fatalln("encode error:", err) }

if err := ioutil.WriteFile("book.bin", out, 0644); err != nil {
  log.Fatalln("write error:", err)
}

in, err := ioutil.ReadFile("book.bin")
if err != nil { log.Fatalln("read error:", err) }

book2 := &pb.AddressBook{}
if err := proto.Unmarshal(in, book2); err != nil {
  log.Fatalln("parse error:", err)
}

package main

import (
  "io/ioutil"
  "log"

  pb "github.com/protocolbuffers/protobuf/examples/go/tutorialpb"
  "google.golang.org/protobuf/proto"
)

func main() {
  // 构造
  p := &pb.Person{
    Id:    1,
    Name:  "Ada",
    Email: "ada@example.com",
    Phones: []*pb.Person_PhoneNumber{
      {Number: "123456", Type: pb.PhoneType_PHONE_TYPE_MOBILE},
    },
  }
  book := &pb.AddressBook{People: []*pb.Person{p}}

  // 写
  data, err := proto.Marshal(book)
  if err != nil { log.Fatal(err) }
  if err := ioutil.WriteFile("book.bin", data, 0644); err != nil { log.Fatal(err) }

  // 读
  raw, err := ioutil.ReadFile("book.bin")
  if err != nil { log.Fatal(err) }
  var got pb.AddressBook
  if err := proto.Unmarshal(raw, &got); err != nil { log.Fatal(err) }

  log.Printf("people: %v", got.People[0].Name)
}