RProtoBuf (version 0.1-0)

Message-class: Class "Message"

Description

R representation of protocol buffer messages. This is a thin wrapper around the Message c++ class that holds the actual message as an external pointer.

Objects from the Class

Objects are typically created by the new function invoked on a Descriptor object.

References

The Message class from the C++ proto library. http://code.google.com/apis/protocolbuffers/docs/reference/cpp/google.protobuf.message.html

See Also

P creates objects of class Descriptor that can be used to create messages.

Examples

# example proto file supplied with this package
proto.file <- system.file( "proto", "addressbook.proto", package = "RProtoBuf" ) 

# reading a proto file and creating the descriptor
Person <- P( "tutorial.Person", file = proto.file )
PhoneNumber <- P( "tutorial.Person.PhoneNumber" )

# creating a prototype message from the descriptor
p <- new( Person )
p$email # not set, returns default value
p$id    # not set, returns default value
as.character( p ) # empty
has( p, "email" ) # is the "email" field set
has( p, "phone" ) # is the "email" field set
length( p )       # number of fields actually set

# update several fields at once
romain <- update( new( Person ), 
	email = "[e-mail]", 
	id = 1, 
	name = "Romain Francois", 
	phone = new( PhoneNumber , number = "+33(0)...", type = "MOBILE" )
	)

# supply parameters to the constructor
dirk <- new( Person, 
	email = "[e-mail]", 
	id = 2, 
	name = "Dirk Eddelbuettel" ) 
# update the phone repeated field with a list of PhoneNumber messages
dirk$phone <- list( 
	new( PhoneNumber , number = "+01...", type = "MOBILE" ), 
	new( PhoneNumber , number = "+01...", type = "HOME" ) )
	
# with/within style
saptarshi <- within( new(Person), {
	id <- 3
	name <- "Saptarshi Guha"
	email <- "[e-mail]" 
} )

# make an addressbook
book <- new( tutorial.AddressBook, person = list( romain, dirk, saptarshi ) )

# serialize the message to a file
tf <- tempfile( )
serialize( book, tf )

# the payload of the message
serialize( book, NULL )

# read the file into a new message
m <- tutorial.AddressBook$read( tf )
writeLines( as.character( m ) )
sapply( m$person, function(p) p$name )