opencog-dev team mailing list archive

["David Hart" <hart@xxxxxxxxxxxx>]

Hi,

Google's work in this area (or something like it) could be used in the
communication layer of a distributed atomSpace, as a faster alternative to
passing and parsing bulky XML.

-dave


Protocol Buffers, our serialized structured data, released as Open
Source<http://google-code-updates.blogspot.com/2008/07/protocol-buffers-our-serialized.html>

from Google Code
Blog<https://www.google.com/reader/view/feed/http%3A%2F%2Ffeeds.feedburner.com%2Fblogspot%2FDcni>by
Dion
Almaer
By Dion Almaer, Google Developer Programs

One of the core pieces of infrastructure at Google is something called Protocol
Buffers <http://code.google.com/apis/protocolbuffers>. We are really pleased
to be open sourcing the
system<http://google-opensource.blogspot.com/2008/07/protocol-buffers-googles-data.html>,
but what are these buffers?

Protocol buffers are a flexible, efficient, automated mechanism for
serializing structured data – think XML, but smaller, faster, and simpler.
You define how you want your data to be structured once, then you can use
special generated source code to easily write and read your structured data
to and from a variety of data streams and using a variety of languages. You
can even update your data structure without breaking deployed programs that
are compiled against the "old" format

It is probably best to take a peak at some code behind this. The first thing
you need to do is define a message type, which can look like the following
.proto file:

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;
}

There is detailed documentation on this
language<http://code.google.com/apis/protocolbuffers/docs/proto.html>for
you to learn more.

Once you have defined a message type, you run a protocol buffer compiler on
the file to create data access classes for your platform of choice (Java,
C++, Python in this release).

Then you can easily work with the data, for example in C++:

Person person;
person.set_name("John Doe");
person.set_id(1234);
person.set_email("jdoe@xxxxxxxxxxx");
fstream output("myfile", ios::out | ios::binary);
person.SerializeToOstream(&output);

We sat down with Kenton Varda, a software engineer who worked on the open
source effort, to get his take on Protocol Buffers, how we ended up with
them, how they compare to other solutions, and more:

-dave