Reading RAW data from an R socket - r

Question

To exchange data very fast between Python and R I programmed a rather dirty solution, which works. On linux and OSX. May it not be that I now have to get this working in windows.
The below code runs a python script that builds a raw vector which can be serialised by RApiSerialise to an R object.
COMMAND = "python"
PATH_TO_SCRIPT='/GetCassandraData.py'
QueryCassandra <- function(query){
allArgs = c(PATH_TO_SCRIPT, query)
output.connection <- rawConnection(raw(length = 0), "r+")
exec_wait(COMMAND, args = allArgs, std_out = output.connection)
output <- rawConnectionValue(output.connection)
close(output.connection)
final <- unserializeFromRaw(output)
return(final)
}
This works as intended on OSX & linux however, windows has the tendancy to put a 0x0d (Carriage return) byte before a 0x0a (line feed) byte which makes RApiSerialise unable to deserialise it.
I am now attempting to solve the problem by communicating through sockets but I do not seem to be able to find a way to read data from a make.socket() object to a raw vector.
I have tried:
data <- read.socket(datasocket)
Which resulted in:
Error in read.socket(datasocket) :
embedded nul in string: 'X\n\0\0\0\002\0\003\004\002\0\002\003\0'
The function read.socket() tries to read a string and doesn't accept null bytes.
Is there a way to read socket data to a raw vector in R?

Answer 1

R server-side:
library(sys)
COMMAND = "python"
PATH_TO_SCRIPT='/lengthCheck.py'
allArgs = c(PATH_TO_SCRIPT)
sys::exec_background(COMMAND, args = allArgs, std_out = TRUE, std_err = TRUE)
datasocket <- socketConnection(port = 1205, server = TRUE, open = "w+b", blocking = TRUE)
on.exit(close(datasocket))
datasize <- readBin(datasocket, what = "double")
data <- readBin(datasocket, what = "raw", n = datasize)
Python client-side:
import struct
import socket
import time
your_raw_array_to_send = bytearray([0x58, 0x0a, 0x00, 0x00, 0x00, 0x02, 0x00, 0x03, 0x04, 0x02, 0x00, 0x02, 0x03, 0x00])
arrayLength = len(your_raw_array_to_send)
datasize = struct.pack('d', arrayLength)
# Wait 100ms for R to set up a listening socket
time.sleep(.100)
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client_socket.connect(('localhost', 1205))
client_socket.send(datasize)
client_socket.send(your_raw_array_to_send)
client_socket.close()