google protocol 入门 demo
ubunbu系统下google protobuf的安装
说明: 使用protobuf时需要安装两部分:
第一部分为*.proto文件的编译器,它负责把定义的*.proto文件生成对应的c++类的.h和.cpp文件;
第二部分是protobuf的c++动态库(由protobuf的源码编译生成),该部分在生成链接生成可执行文件时需要使用到。
1. 安装编译google protobuf源文件时需要的依赖文件
sudo apt-get install autoconf automake libtool curl make g++ unzip
2. 下载google protobuf 的c++对应的源码,并解压至当前目录中
wget https://github.com/protocolbuffers/protobuf/releases/download/v3.11.2/protobuf-cpp-3.11.2.tar.gz
tar -xf protobuf-cpp-3.11.2.tar.gz
3. 进入解压后的目录,并安装
./configure
make
make check
sudo make install
sudo make ldconfig
google protobuf的使用
1. 新建一个表示电话薄的addressbook.proto文件
touch addressbook.proto
echo 'syntax = "proto2";
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 phones = 4;
}
message Addressbook {
repeated Person people = 1;
}
' > addressbook.proto
2. 使用porotc编译器生成address.proto对应的*.cpp和*.h文件,运行以下命令生成了addressbook.pb.cc和addressbook.pb.h文件。
protoc addressbook.proto
3. 创建两个读与写电话薄的*.cpp文件,使用google protobuf完成写与读的功能。
- 写文件:
touch write_message.cpp
echo '#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 for finish): ";
string number;
getline(cin, number);
if (number.empty())
break;
tutorial::Person::PhoneNumber* phone_number = person->add_phones();
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 if (type == "work")
phone_number->set_type(tutorial::Person::WORK);
else
cout << "Unkown 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_people());
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;
}
' > write_message.cpp
- 读文件:
touch read_message.cpp
echo '#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.people_size(); ++i) {
const tutorial::Person& person = address_book.people(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.phones_size(); ++j) {
const tutorial::Person::PhoneNumber& phone_number = person.phones(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;
}
' > read_message.cpp
4. 分别编译write_message.cpp文件和read_message.cpp文件(其中pkg-config命令可以输出关于protobuf动态库相关的编译时的参数)
g++ write_message.cpp addressbook.pb.cc -o write.out $(pkg-config --cflags --libs protobuf)
g++ read_message.cpp addressbook.pb.cc -o read.out $(pkg-config --cflags --libs protobuf)
5. 分别运行write.out和read.out文件进行写与读操作
./write.out result.protobuf
./read.out result.protobuf