R/socketClientConnection.R

In adamryczkowski/svSocket: SciViews - Socket Server

socketClientConnection <- function (client, serverport = 8888, socket,
blocking = FALSE, open = "a", encoding = getOption("encoding"))
{
	## Only accepts "a" or "w" modes currently
	if (!open %in% c("a", "w"))
		stop("Only modes \"a\" or \"w\" are currently supported")
	
	## Connect to a client of the svSocket server, serving on 'serverport'
	## First check that the server is running and is serving 'socket'
	if (is.null(serverport) || !is.numeric(serverport[1]) || serverport[1] < 1) 
        stop("'serverport' must be a positive integer!")
    portnum <- round(serverport[1])
	if (!portnum %in% getSocketServers())
		stop("There is no currently running socket server on port ",
			portnum, "\n    Start one by using startSocketServer() first")
	## If socket is not provided, try to get it from client's infos
	if (missing(socket))
		socket <- parSocket(client, serverport)$clientsocket
	## Check that 'socket' is a currently opened Tcl socket and is a client
	res <- try(.Tcl(paste("fconfigure", socket, "-peername")), silent = TRUE)
	if (inherits(res, "try-error"))
		stop("This client or this socket is not currently connected")
	res <- as.character(res)
	redir <- paste("->", res[1], ":", res[length(res)], sep = "")
	## That's OK, we could proceed in opening a socketConnection and redirect it
	## to the client's socket...
#	currSocks <- getSocketClientsNames(portnum)
	sck <- socketConnection(host = "127.0.0.1", port = portnum, server = FALSE,
		blocking = blocking, open = open, encoding = encoding)
	## We need to leave enough time in the background to Tcl to establish the
	## connection
#	i <- 0
#	mySock <- character(0)
#	while (length(mySock) < 1 && i < 10) {
#		i <- i + 1
		.Tcl("update idletasks")
#		Sys.sleep(0.05)
#		currSocks2 <- getSocketClientsNames(portnum)
#		mySock <- currSocks2[!currSocks2 %in% currSocks]
#	}
#	if (length(mySock) < 1) {
#		try(close(sck), silent = TRUE)
#		stop("Unable to connect to the client socket")
#	}
#	mySock <- mySock[1]  # Just a precaution
	## Now, activate the redirection in Tcl
#	.Tcl(paste("fileevent", mySock, "readable [list sockRedirect", mySock,
#		socket, "]"))
	## ... and eliminate this client for the list
#	.Tcl(paste("unset Rserver_", portnum, "(", mySock, ")", sep = ""))
	
	## Instruct the socket server to redirect to socket
	cat(">>>>>>", socket, "\n", sep = "", file = sck)
	.Tcl("update idletasks")
	
	## Finalize the "sockclientconn" object
#	attr(sck, "conn_tclsocket") <- mySock
	attr(sck, "conn_redirsocket") <- socket
	attr(sck, "conn_redirection") <- redir
	class(sck) <- c("sockclientconn", class(sck))
	return(sck)
}

## Summary method for sockclientconn object
summary.sockclientconn <- function (object, ...)
{
	obj2 <- object
	class(obj2) <- "connection"
	res <- summary(obj2)
	## Change description and class
	res$description <- attr(object, "conn_redirection")
	res$class <- "sockclientconn"
	return(res)
}