I'm trying to implement a connection between two processes using a
simple socket mechanism. The messages are rather long object stored as
JSON.
R is crashing with a segmentation fault when I try to read my test
message (which is 5305 bytes long). I first send the length in bytes
and then I send the actual message.
Here is my R code:
library(jsonlite)
library(futile.logger)
listenerloop <- function (port) {
flog.trace("Opening Socket on port %d",port)
sock <- make.socket("localhost",port,server=TRUE)
on.exit({
close.socket(sock)
flog.trace("Closing Socket on port %d",port)
})
repeat {
## Input a hunk of stuff up to a blank line.
output <- character()
repeat {
inlen <- read.socket(sock,loop=TRUE)
flog.trace("Got message of length %s",inlen)
if (inlen=="quit") break
inmess <- fromJSON(read.socket(sock,as.integer(inlen)),false)
outmess <- doProcess(inmess)
output <- toJSON(outmess)
flog.trace("Sending message of length %s",nchar(output))
write.socket(sock,paste(nchar(output),"\n"))
write.socket(sock,output)
}
}
}
doProcess() is the payload, but it is not getting that far. Instead I get:
> listenerloop(12525)
TRACE [2020-05-11 15:21:00] Opening Socket on port 12525
TRACE [2020-05-11 15:21:03] Got message of length 5305
{"StudentRecord":null,"Message":{"_id":624,"app":"ecd://terc.edu/Zoombinis/","uid":2,"context":"PIZZA_PASS1","sender":"DataArcade","mess":"Last
Transaction","timestamp":"1570279373.109","processed":false,"data":{"PP29_N_Rejects_Current_Z":0,"PP106_Avg
*** caught segfault ***
address 0x7ffdf533d0a8, cause 'memory not mapped'
Traceback:
1: read.socket(sock, as.integer(inlen))
2: fromJSON(read.socket(sock, as.integer(inlen)), false)
3: listenerloop(12525)
I have two questions:
1) Can somebody file a bug report on this? I strongly suspect that
there is an uncaught error in read.socket(). I'm happy to help, but I
don't have access to bugzilla.
2) Anybody know how to read/write long messages to a socket in R?
Thanks in advance.
--Russell Almond
--
Russell G. Almond
https://ralmond.net
alm...@acm.org
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