Set locale to system default UTF-8

Question

When running R inside rApache, the locale is inherited from the Apache webserver, and therefore Sys.getlocale() is always equal to "C". I would like my web application to use UTF8, so I use:

Sys.setlocale("LC_ALL", 'en_US.UTF-8')

However this doesn't work on machines that do not have this locale available:

1: Setting LC_CTYPE failed, using "C" 
2: Setting LC_COLLATE failed, using "C" 
3: Setting LC_TIME failed, using "C" 
4: Setting LC_MESSAGES failed, using "C" 
5: Setting LC_MONETARY failed, using “C”

Is there any way to use Sys.setlocale to set the locale to the system default UTF-8? I.e. something that would also work on Windows or a German Linux?

Answer 1

Answering my own question: On Ubuntu the default LANG is defined in /etc/default/locale:

jeroen@dev:~⟫ cat /etc/default/locale
# Created by cloud-init v. 0.7.7 on Wed, 29 Jun 2016 11:02:51 +0000
LANG="en_US.UTF-8"

So in R we could do something like:

readRenviron("/etc/default/locale")
LANG <- Sys.getenv("LANG")
if(nchar(LANG))
   Sys.setlocale("LC_ALL", LANG)

Apache also has a line in /etc/apache2/envvars that can be uncommented to enable this.