R/tdCheckConn.R

In tranlm/tdR: Teradata interaction and query package

# TODO: Checks for Teradata connection
#
# Author: Linh Tran
# Date: Mar 10, 2016
# Email: Linh_m_tran@apple.com
###############################################################################



tdCheckConn = function(...) {

	args = list(...)[[1]]
	argNames = names(args)

	if ("conn" %in% argNames) {
		conn = args$conn
		if(is.null(attr(conn, "tmpConnection"))) attr(conn, "tmpConnection") = FALSE

	} else if ("username" %in% argNames & "password" %in% argNames) {
		message("Establishing connection with provided details.")
		if ('classPath' %in% argNames) {
			classPath=args$classPath
		} else classPath=NULL
		if ('addr' %in% argNames) {
			addr = args$addr
			if ("db" %in% argNames) {
				conn = with(args, tdConn(username=username, password=password, addr=addr, db=db, classPath=classPath))
			} else conn = with(args, tdConn(username=username, password=password, addr=addr, classPath=classPath))
		} else {
			if ("db" %in% argNames) {
				conn = with(args, tdConn(username=username, password=password, db=db, classPath=classPath))
			} else conn = with(args, tdConn(username=username, password=password, classPath=classPath))
		}
		attr(conn, "tmpConnection") = TRUE

	} else {
		conn = try(get("conn", envir=.GlobalEnv), TRUE)
		if(is.null(attr(conn, "tmpConnection"))) attr(conn, "tmpConnection") = FALSE
		if(inherits(conn, "try-error")) {
			message("No connection provided. Attempting to connect.")
			conn = tdConn()
			attr(conn, "tmpConnection") = TRUE
		}
		if(inherits(conn, "try-error")) {
			stop("No connection or connection profile detected.")
		}
	}

	return(conn)

}