R curl::has_internet() FALSE even though there are internet connection - r

Question

My problem arose when downloading data from EuroSTAT using the R package eurostat:
# Population data by NUTS3
pop_data <- subset(eurostat::get_eurostat("demo_r_pjangrp3", time_format = "num"),
(age == "TOTAL") & (sex == "T") &
(nchar(trimws(geo)) == 5))[, c("time","geo","values")]
#Fejl i eurostat::get_eurostat("demo_r_pjangrp3", time_format = "num") :
# You have no internet connection, please reconnect!
Seaching, I have found out that it is the statement (in the eurostat-package code):
if (curl::has_internet() {stop("You have no inernet connection, please connnect") that cause the problem.
However, I have interconnection and can e.g. ping www.eurostat.eu
I have tried curl::has_internet() on different computers, all with internet connection. On some it work (respond TRUE) on others it don't.
I have talked with our IT department, and we tried if it could be a firewall problem. Removing the firewall, did not solve the problem.
Unfortunately, I am ignorant on network-settings. Hence, when trying to read the documentation for the curl-package I am lost.
Downloading data from EuroSTAT using the command above have worked for the last at least 2 years, and for me the problem arose at the start of 2020 (January 7).
Hope someone can help with this, as downloading population data from EuroSTAT is a mandatory part in more of my/our regular work.

Answer 1

In the special case of curl::has_internet, you don't need to modify the function to return a specific value. It has its own enclosing environment, from which it reads a state variable indicating whether a proxy connection exists. You can modify that state variable instead.
assign("has_internet_via_proxy", TRUE, environment(curl::has_internet))
curl::has_internet() # will always be TRUE
# [1] TRUE

Answer 2

It's difficult to tell without knowing your settings but there are a couple of things to try. This issue has been noted and possibly addressed in a development version which you can install with
install.packages("https://github.com/jeroen/curl/archive/master.tar.gz", repos = NULL)
You could also try updating libcurl, which is the C library for which the R package acts as an R interface. The problem you describe seems to be more common with older versions of libcurl.
If all else fails, you could overwrite the curl::has_internet function like this:
remove_has_internet <- function()
{
unlockBinding(sym = "has_internet", asNamespace("curl"))
assign("has_internet", function() return(TRUE), envir = asNamespace("curl"))
lockBinding(sym = "has_internet", asNamespace("curl"))
}
Now if you run remove_has_internet(), any call to curl::has_internet() will return TRUE for the remainder of your R session. However, this will only work if other curl functionality is working properly with your network settings. If it isn't then you will get other strange errors and should abandon this approach.
If, for any reason, you want to restore the functionality of the original curl::has_internet without restarting an R session, you can do this:
restore_has_internet <- function()
{
unlockBinding(sym = "has_internet", asNamespace("curl"))
assign("has_internet",
function() {!is.null(nslookup("r-project.org", error = FALSE))},
envir = asNamespace("curl"))
lockBinding(sym = "has_internet", asNamespace("curl"))
}

Answer 3

I just got into this problem, so here's an additional solution, blending both previous answers. It's reversible and checks if we actually have internet to avoid bigger problems later.
# old value
op = get("has_internet_via_proxy", environment(curl::has_internet))
# check for internet
np = !is.null(curl::nslookup("r-project.org", error = FALSE))
assign("has_internet_via_proxy", np, environment(curl::has_internet))
Within a function, this line can be added to automatically revert the process:
on.exit(assign("has_internet_via_proxy", op, environment(curl::has_internet)))