Duncan:
    I set Firefox as the default browser; didn't need to delete and
reinstall.  Problem solved - now help is working properly; opening the
documents in Firefox.  By the by, despite IE's failings, the tab preview
feature, when hovering the mouse over the icon on Windows 7 taskbar, is
pretty good.

Thanks so much,
Jonathan

On Thu, Feb 4, 2010 at 6:29 AM, S Ellison <S.Ellison@lgc.co.uk> wrote:

> Might this be a firewall-like issue and nothing to do with html or R?
>
> If I understand the 2.10 help system, it operates by starting R as an
> http server - effectively a web server, operating on the local machine
> (127.0.0.1) with an unusual IP port (which doesn;t seem to be consistent
> from one run to the next, perhaps because it's taking a randomly or
> first available port in the high range).
> That established R as the default server for http requests made to the
> machine with the particular port specified, yes?
>
>
> The 'obvious' OS-related thing that could break this is a firewall
> restriction on access to http on ports other than 80 and 8080, the
> typical default ports. That could arise either because of incoming or
> outgoing IP port resrtrictions; the firewall could either stop an
> application asking for an odd port, or could stop R serving it.
>
> It's unusual for a firewall to prevent access to th elocal host
> (127.0.0.1) but it might be worth checking.
>
> It could be fixed (or at least checked) by looking at the firewall
> settings to see whether there were any port-specific restrictions (eg
> 'only allow http on ports 80 and 8080'  or equivalent).
>
> Another possibility is to check the browser and OS http proxy options;
> if they are set to point to a proxy _every time including local access
> requests_ you'll presumably have similar problems.
>
> Incidentally, i haven;t yet broached the idea of R acting as an http
> server every time it calls help with our IT security folk; I'm rather
> afraid of the possible consequence.  Call me paranoid if you like ...
> but the depth of explanation they might require could be daunting.
>
> Steve Ellison
>
> >>> Duncan Murdoch <murdoch@stats.uwo.ca> 04/02/2010 00:45:21 >>>
> On 03/02/2010 7:17 PM, Jonathan wrote:
> > Duncan:
> >    I suspect that you're right about the file association having been
> the
> > issue.  .html files were not associated with either browser.
> However, I
> > fixed that by associating .html files with Firefox, but R still gave
> me the
> > same error!  If that was the problem, R didn't realize the
> association had
> > been changed.
> >
> > I tried uninstalling R and reinstalling R, thinking maybe it takes a
> > snapshot of associations once (at install), and keeps its own
> internal table
> > (even though that didn't sound all that intuitive).  No luck; R
> still
> > persisted in being unable to open help files.
>
> R knows nothing about the associations.  They are handled by the
> Windows
> shell functions.
>
> And it's not .html files; Windows recognizes that the URL is a URL, and
>
> sends it to whichever browser has registered itself to handle them.
>
> So you might fix things by deleting and re-installing Firefox, telling
>
> it to install itself as the default browser.  (Or tell IE to reinstall
>
> itself as the default, if you really want to do that.)
>
> You can also set up a shortcut to a URL ("New shortcut" from the
> context
> menu on the desktop) and give it the URL that R tried.  This isn't a
> solution at all, since the URL only works for the current R session
> unless you set it to a fixed one with options(help.ports=12345), but it
>
> might give some more insight into what's wrong.
>
> Duncan Murdoch
>
> >
> > Then I rebooted my machine.  I'm still getting the same error.
> > Any other ideas?
> >
> > Thanks,
> > Jon
> >
> > On Wed, Feb 3, 2010 at 5:57 PM, Duncan Murdoch <murdoch@stats.uwo.ca>
> wrote:
> >
> >> On 03/02/2010 5:14 PM, Jonathan wrote:
> >>
> >>> Rich:
> >>>    Both IE and Firefox are unable to find the link you supplied.
> However,
> >>> that's only because I've restarted my R session since I pasted the
> error
> >>> output (and it appears that each time I restart R, the URL is
> slightly
> >>> different).  This time, I get:
> >>>
> >>> ?sum
> >>> starting httpd help server ... done
> >>> Error in shell.exec(url) :
> >>>  access to 'http://127.0.0.1:31836/library/base/html/sum.html'
> denied
> >>>  ---
> >>> If I paste the new URL into either browser, I can read the entry
> without
> >>> issue.  This is what I've been doing to read help entries, but
> it's
> >>> tedious
> >>> to copy and paste the URL into a browser every time I want to read
> the
> >>> entry
> >>> for a particular function..
> >>>
> >>> Happy to hear any other ideas!
> >>>
> >>>
> >> What happens if you paste that into the "Run" box on the start menu?
>  It
> >> looks to me as though the association between URLs and your browser
> is
> >> broken.
> >>
> >> Another likely problem is antivirus software.  If you can
> temporarily turn
> >> it off, see if that helps.
> >>
> >> Duncan Murdoch
> >>
> >
>
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