[R] Using Internet proxies
ripley at stats.ox.ac.uk
Wed Jan 22 20:08:02 CET 2003
There have been quite a few questions recently about this, so I have
tried to gather experience. I set up a proxy using Apache2 (a very common
server) behind our firewall and tried various authentication approaches.
One comment: all the methods return error messages when they fail. Please
don't report `it doesn't work' without the full details.
1) For a proxy that authenticates at most by hostname/IP address, and for
Windows users, just set up IE6 to work, and use the --internet2
command-line flag. This worked for me (despite various claims here).
2) For a proxy that authenticates at most by hostname/IP address, the
internal download.file method works, provided you set the environment
variable http_proxy or HTTP_PROXY correctly, e.g. in ~/.Renviron.
This is almost of the same form as used by wget, but is less tolerant,
and note that setting `no_proxy' disables the proxy for all sites (unlike
3) If you have a proxy that demands that you enter a username/password
combination, you can use the internal download method in R-devel: see
4) Installing wget and using the options(download.file.method="wget")
provides a highly tunable approach. For Windows users, wget is still
available on http://www.stats.ox.ac.uk/pub/Rtools.
Note that none of these methods support proxies that want more advanced
methods of authentication, e.g. Digest under HTTP/1.1. If there are
any such proxies, please can a user provide us with a proven method.
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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