protobuf示例

1, 下载compiler和源代码
http://code.google.com/p/protobuf/downloads/

build protobuf:

./configure
make
make check
make install

2, 创建一个addressbook.proto

package tutorial;

message Person {
  required string name = 1;
  required int32 id = 2;
  optional string email = 3;
  
  enum PhoneType {
    MOBILE = 0;
    HOME = 1;
    WORK = 2;
  }
  
  message PhoneNumber {
    required string number = 1;
    optional PhoneType type = 2 [default = HOME];
  }
  
  repeated PhoneNumber phone = 4; 
}

message AddressBook {
  repeated Person person = 1;
}

3, 生成C++的stub

protoc --cpp_out=. ./addressbook.proto

运行上面的命令将生成addressbook.pb.h和addressbook.pb.cc

4, 写

// write.cc
#include <iostream>
#include <fstream>
#include <string>
#include "addressbook.pb.h"
using namespace std;

void PromptForAddress(tutorial::Person* person) {
	cout << "Enter person ID number: ";
	int id;
	cin >> id;
	person->set_id(id);
	cin.ignore(256, '\n');

	cout << "Enter name: ";
	getline(cin, *person->mutable_name());

	cout << "Enter email address (blank for none): ";
	string email;
	getline(cin, email);
	if (!email.empty()) {
		person->set_email(email);
	}

	while(true) {
		cout << "Enter a phone number (or leave blank to finish):";
		string number;
		getline(cin, number);
		if (number.empty()) {
			break;
		}

		tutorial::Person::PhoneNumber *phone_number = person->add_phone();
		phone_number->set_number(number);

		cout << "Is this a mobile, home, or work phone?";
		string type;
		getline(cin, type);
		if (type == "mobile") {
			phone_number->set_type(tutorial::Person::MOBILE);
		} else if (type == "home") {
			phone_number->set_type(tutorial::Person::HOME);
		} else {
			cout << "Unknown phone type. Using default." << endl;
		}
	}
}

int main(int argc, char* argv[]) {
	GOOGLE_PROTOBUF_VERIFY_VERSION;

	if(argc != 2) {
		cerr << "Usage: " << argv[0] << " ADDRESS_BOOK_FILE" << endl;
		return -1;
	}

	tutorial::AddressBook address_book;

	{
		fstream input(argv[1], ios::in | ios::binary);
		if (!input) {
			cout << argv[1] << ": File not found. Creating a new file." << endl;
		} else if (!address_book.ParseFromIstream(&input)) {
			cerr << "Failed to parse address book." << endl;
			return -1;
		}
	}

	PromptForAddress(address_book.add_person());
	{
		fstream output(argv[1], ios::out | ios::trunc | ios::binary);
		if (!address_book.SerializeToOstream(&output)) {
			cerr << "Failed to write address book." << endl;
			return -1;
		}
	}

	google::protobuf::ShutdownProtobufLibrary();

	return 0;
}

编译生成write.exe
注意：
需要将protobuf的源码以及lib加到编译的PATH中

向文件写数据:

write ADDRESS_BOOK_FILE

Enter person ID number: 123
Enter name: Hideto
Enter email address (blank for none): [e-mail]
Enter a phone number (or leave blank to finish):159xxxxxxxx
Is this a mobile, home, or work phone?mobile
Enter a phone number (or leave blank to finish):

write ADDRESS_BOOK_FILE
// ....

5, 读

// read.cc
#include <iostream>
#include <fstream>
#include <string>
#include "addressbook.pb.h"
using namespace std;

void ListPeople(const tutorial::AddressBook& address_book) {
    for (int i = 0; i < address_book.person_size(); i++) {
        const tutorial::Person& person = address_book.person(i);

        cout << "Person ID: " << person.id() << endl;
        cout << "Name: " << person.name() << endl;
        if(person.has_email()) {
            cout << "E-mail address: " << person.email() << endl;
        }

        for (int j = 0; j < person.phone_size(); j++) {
            const tutorial::Person::PhoneNumber& phone_number = person.phone(j);

            switch (phone_number.type()) {
                case tutorial::Person::MOBILE:
                    cout << "Mobile phone #: ";
                    break;
                case tutorial::Person::HOME:
                    cout << "Home phone #: ";
                    break;
                case tutorial::Person::WORK:
                    cout << "Work phone #: ";
                    break;
            }
            cout << phone_number.number() << endl;
        }
    }
}

int main(int argc, char* argv[]) {
    GOOGLE_PROTOBUF_VERIFY_VERSION;

    if (argc != 2) {
        cerr << "Usage: " << argv[0] << "ADDRESS_BOOK_FILE" << endl;
        return -1;
    }

    tutorial::AddressBook address_book;
    {
        fstream input(argv[1], ios::in | ios::binary);
        if (!address_book.ParseFromIstream(&input)) {
            cerr << "Failed to parse address book." << endl;
            return -1;
        }
    }

    ListPeople(address_book);

    google::protobuf::ShutdownProtobufLibrary();

    return 0;
}

编译生成read.exe
从文件读数据:

read ADDRESS_BOOK_FILE

// 以下为输出
Person ID: 123
Name: Hideto
E-mail address: [e-mail]
Mobile phone #: 159xxxxxxxx
Person ID: 456
Name: chuang
E-mail address: [e-mail]
Home phone #: [phone]
Person ID: 1231231
Name: asdfadsf
E-mail address: [e-mail]
Mobile phone #: [phone]
Home phone #: [phone]

6, Ruby的protobuf库
http://code.google.com/p/ruby-protobuf/
安装:

gem install ruby_protobuf

生成ruby的stub:

rprotoc addressbook.proto

从文件读数据:

# read.rb
require 'addressbook.pb.rb'

def list_people(address_book)
  address_book.person.each do | p |
    p "Person ID: #{p.id}"
    p "Name: #{p.name}"
    p "E-mail: #{p.email}" unless p.email.empty?
    p.phone.each do |phone|
      case phone.type
      when Tutorial::Person::PhoneType::MOBILE
        print "Mobile phone #: "
      when Tutorial::Person::PhoneType::HOME
        print "Home phone #: "
      when Tutorial::Person::PhoneType::WORK
        print "Work phone #: "
      end
      p phone.number
    end
  end
end

address_book = Tutorial::AddressBook.new
address_book.parse_from_file ARGV[0]

list_people address_book

运行:

ruby read.rb 'D:\cpp-projects\pb\bin\Release\ADDRESS_BOOK_FILE'

// 输出
"Person ID: 123"
"Name: Hideto"
"E-mail: [e-mail]"
Mobile phone #: "159xxxxxxxx"
"Person ID: 456"
"Name: chuang"
"E-mail: [e-mail]"
Home phone #: "22222222"
"Person ID: 1231231"
"Name: asdfadsf"
"E-mail: [e-mail]"
Mobile phone #: "12321321321"
Home phone #: "123432432"