Ping: ping a Uniform resource locator (URL)

In Ecfun: Functions for Ecdat

Description

***NOTE: THIS IS A PRELIMINARY VERSION OF THIS FUNCTION; ***NOTE: IT MAY BE CHANGED OR REMOVED IN A FUTURE RELEASE.

ping a Uniform resource locator (URL) or Internet Protocol (IP) address.

NOTE: Some Internet Service Providers (ISPs) play games with "ping". That makes the results of Ping unreliable.

Usage

Ping(url, pingArgs='', warn=NA,
     show.output.on.console=FALSE)

Arguments

url	a character string of a URL or IP address to ping. If url is a vector of length greater than 1, only the first component is used.
pingArgs	arguments to pass to the ping command of typical operating systems via pingResult <- system(paste('ping', pingArgs, url), intern=TRUE, ...)
warn	value for options('warn') during the call to system. NA to not change options('warn') during this call.
show.output.on.console	argument for system.

Details

1. urlSplit0 <- strsplit(url, '://')[[1]]

2. urlS0 <- urlSplit0[min(2, length(urlSplit0))]

3. host <- strsplit(urlS0, '/')[[1]][1]

4. pingCmd <- paste('ping', pingArgs, host)

5. system(pingCmd, intern=TRUE, ...)

Value

list with the following components:

rawResults	character vector of the raw results from the ping command
rawNumbers	numeric vector of the times measured
counts	numeric vector of numbers of packets sent, received, and lost
p.lost	proportion lost = lost / sent
stats	numeric vector of min, avg (mean), max, and mdev (standard deviation) of the measured round trip times

Author(s)

Spencer Graves

See Also

system, options

Examples

##
## Some ISPs play games with ping.
## Therefore, the results are not reliable.
##
## Not run: 
##
## good
##
(google <- Ping('http://google.com/ping works on host not pages'))

\dontshow{stopifnot(}
with(google, (counts[1]>0) && (counts[3]<1))
\dontshow{)}

##
## ping oops <<-- at one time, this failed.
##      However, with some ISPs, it works, so don't test it.
##

##
(couldnotfindhost <- Ping('oops'))

\dontshow{stopifnot(}
with(couldnotfindhost,
     length(grep('could not find host', rawResults))>0)
\dontshow{)}

##
## impossible, but not so obvious
##
(requesttimedout <- Ping('requesttimedout.com'))

\dontshow{stopifnot(}
with(requesttimedout, (counts[1]>0) && (counts[2]<1) &&
         (counts[3]>0))
\dontshow{)}

## End(Not run)

Ecfun documentation built on May 2, 2019, 6:53 p.m.