How to determine if you have an internet connection in R

Question

Sometimes I need to download data from the internet. On occasions this has failed either because the website is down or because my computer has lost its internet connection.

Answer 1

Just another one to add to the pot, inspired by @romans answer, this works only on Windows I'd assume, not sure about other platforms:

canPingSite <- function(test.site) {
    !as.logical(system(paste("ping", test.site)))
}

Which we test as follows:

> t1 <- canPingSite("www.yahoo.com")
[...]

> t2 <- canPingSite(";lkjsdflakjdlfhasdfhsad;fs;adjfsdlk")
[...]

> t1; t2
[1] TRUE
[1] FALSE