download.file2 <- function (url, destfile = NULL, method, quiet = FALSE, mode = "w", cacheOK = TRUE, extra = getOption("download.file.extra"))
{
if (is.null(destfile)) destfile <- basename(url)
else destfile
method <- if (missing(method))
getOption("download.file.method", default = "auto")
else match.arg(method, c("auto", "internal", "libcurl", "wget",
"curl", "lynx"))
if (method == "auto") {
if (length(url) != 1L || typeof(url) != "character")
stop("'url' must be a length-one character vector")
method <- if (grepl("^file:", url))
"internal"
else "libcurl"
}
switch(method, internal = {
status <- .External(C_download, url, destfile, quiet,
mode, cacheOK)
if (!quiet) flush.console()
}, libcurl = {
status <- .Internal(curlDownload(url, destfile, quiet,
mode, cacheOK))
if (!quiet) flush.console()
}, wget = {
if (length(url) != 1L || typeof(url) != "character") stop("'url' must be a length-one character vector")
if (length(destfile) != 1L || typeof(destfile) != "character") stop("'destfile' must be a length-one character vector")
if (quiet) extra <- c(extra, "--quiet")
if (!cacheOK) extra <- c(extra, "--cache=off")
status <- system(paste("wget", paste(extra, collapse = " "),
shQuote(url), "-O", shQuote(path.expand(destfile))))
if (status) stop("'wget' call had nonzero exit status")
}, curl = {
if (length(url) != 1L || typeof(url) != "character") stop("'url' must be a length-one character vector")
if (length(destfile) != 1L || typeof(url) != "character") stop("'destfile' must be a length-one character vector")
if (quiet) extra <- c(extra, "-s -S")
if (!cacheOK) extra <- c(extra, "-H 'Pragma: no-cache'")
status <- system(paste("curl", paste(extra, collapse = " "),
shQuote(url), " -o", shQuote(path.expand(destfile))))
if (status) stop("'curl' call had nonzero exit status")
}, lynx = stop("method 'lynx' is defunct", domain = NA))
if (status)
warning("download had nonzero exit status")
invisible(status)
}