computers and technology & interesting & linux, unix, and open source & news & programming 09 Jul 2008 09:19 am

Protocol Buffers: Google’s Data Interchange Format

Google’s open source’s “Protocol Buffers”. Here’s some examples:

You write a .proto file like this: 

message Person {
  required int32 id = 1;
  required string name = 2;
  optional string email = 3;
}

Then you compile it with protoc, the protocol buffer compiler, to produce code in C++, Java, or Python.

Then, if you are using C++, you use that code like this: 

Person person;
person.set_id(123);
person.set_name("Bob");
person.set_email("bob@example.com");

fstream out("person.pb", ios::out | ios::binary | ios::trunc);
person.SerializeToOstream(&out);
out.close();

Or like this: 

Person person;
fstream in("person.pb", ios::in | ios::binary);
if (!person.ParseFromIstream(&in)) {
  cerr << "Failed to parse person.pb." << endl;
  exit(1);
}

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

Read more about them: Google Open Source Blog: Protocol Buffers: Google’s Data Interchange Format

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