That was misleading advice. R is a C program and accesses the environment via the C calls getenv and (on Windows) putenv. This is not Windows scripting (Grothendieck's earlier reference): the C runtime maintains only one environment block.
I've re-checked, and suspect the problem is in the following comment in ?download.file These environment variables must be set before the download code is first used: they cannot be altered later by calling 'Sys.setenv'. If I have http_proxy set in the environment, the proxy is not used in any of the following cases: - Calling R from a shortcut with http_proxy="" on the target (see the rw-FAQ). - Calling R from a shortcut with no_proxy="*" on the target. - Using Sys.unsetenv("http_proxy") right at the start of the R session. - Using Sys.setenv(no_proxy="*") right at the start of the R session. If you set options(internet.info=0) you will see exactly what is tried. Another possibility is that R is being used with --internet2, in which case none of this applies, and the simple answer is not to use --internet2 at home. On Tue, 29 May 2007, Gabor Grothendieck wrote: > You can have 4 different http_proxy environment variables and if you > set one type but try to unset a different type then that will have no > effect on the one you originally set. For example, if you originally > set it as a system or user environment variable and then try to > unset the process environment variable of the same name then > that will have no effect on the system or user environment variable. > > On 5/29/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: >> Hi Gabor, >> >> Thanks for the reply and link. >> >> I took a look at the link -- one thing I don't understand is why if I delete >> the 'http_proxy' variable via the cmd shell (or equivalent OS dialog box), >> why I can get R to ignore the proxy, but using Sys.setenv("http_proxy"="") >> won't do that for me (at least for the scope of the session). If there were >> other variables affecting it, I would think my deleting 'http_proxy' in the >> OS would also have no effect -- yet it does. >> >> Any ideas? >> >> Thanks again, >> Matt >> >> >> -----Original Message----- >> From: Gabor Grothendieck [mailto:[EMAIL PROTECTED] >> Sent: Tue 5/29/2007 9:49 PM >> To: Pettis, Matthew (Thomson) >> Cc: r-help@stat.math.ethz.ch >> Subject: Re: [R] http proxies: setting and unsetting >> >> Note that Windows XP has 4 types of environment variables and I suspect >> that the problem stems from not taking that into account: >> >> http://www.microsoft.com/technet/scriptcenter/guide/sas_wsh_kmmj.mspx?mfr=true >> >> On 5/29/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: >>> Hi, >>> >>> I am trying to use R at work and at home on the same computer. At work, I >>> have a proxy, and at home, I do not. I have, for work, a User environment >>> variable "http_proxy" which I set in the OS (Windows XP Pro). When I am at >>> work, and I try to retrieve data from the web with 'read.csv', things work >>> just fine. I assume it knows how to use the proxy. >>> >>> The trouble is when I am at home and have no proxy, R still tries to use my >>> work proxy. I have tried the following: >>> >>> Sys.setenv("http_proxy"="") >>> Sys.setenv("no_proxy"=TRUE) >>> Sys.setenv("no_proxy"=1) >>> >>> none of which seems to work. Whenever I try to use read.csv, it tells me >>> that it cannot find my work proxy, which I am trying to tell R to ignore. >>> >>> I can solve this problem by removing the http_proxy environment variable >>> binding in the OS when at home, but that is a pain, because then I have to >>> reset it when I go back into work. >>> >>> Is there a way to tell R within a session to ignore the proxy? If so, what >>> am I doing wrong? >>> >>> thanks, >>> matt >>> >>> ______________________________________________ >>> R-help@stat.math.ethz.ch mailing list >>> https://stat.ethz.ch/mailman/listinfo/r-help >>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >>> and provide commented, minimal, self-contained, reproducible code. >>> >> >> > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > -- Brian D. Ripley, [EMAIL PROTECTED] 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 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.