We (Dirk and I) released the initial version of our package RProtoBuf to CRAN this week. This packages brings google's protocol buffers to R

I invite you to check out the main page for protobuf to find the language definition for protocol buffers as well as tutorial for officially (i.e. by google) supported languages (python, c++ and java) as well as the third party support page that lists language bindings offered by others (including our RProtoBuf package.

Protocol buffers are a language agnostic data interchange format, based on a using a simple and well defined language. Here comes the classic example that google uses for C++, java and python tutorials.

First, the proto file defines the format of the message.

Then you need to teach this particular message to R, which is simply done by the readProtoFiles function.

> readProtoFiles( "addressbook.proto" )

Now we can start creating messages :

> person 

And then access, modify fields of the message using a syntax extremely close to R lists

> person$email  person$name 

In R, protobuf messages are stored as simple S4 objects of class "Message" that contain an external pointer to the underlying C++ object. The Message class also defines methods that can be accessed using the dollar operator

> # write a debug version of message
> # this is not how it is serialized
> writeLines( person$toString() )
name: "Romain Francois"
id: 1234
email: "francoisromain@free.fr"

> # serialize the message to a file
> person$serialize( "somefile" )


The package already has tons of features, detailed in the vignette

> vignette( "RProtoBuf" )


.. and there is more to come