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

Bioconductor's Biobase package has a function for testing internet connection.

Biobase::testBioCConnection()

Below is a heavily modified version of this function for testing ability to read lines from a URL.

can_internet <- function(url = "http://www.google.com") {

    # test the http capabilities of the current R build
    if (!capabilities(what = "http/ftp")) return(FALSE)

    # test connection by trying to read first line of url
    test <- try(suppressWarnings(readLines(url, n = 1)), silent = TRUE)

    # return FALSE if test inherits 'try-error' class
    !inherits(test, "try-error")
}

can_internet()