[R] URL error when trying to use help function in R [Sec: UNOFFICIAL]

[Duncan Murdoch]

On 12/09/2010 3:50 PM, Gosse, Michelle wrote:
> Thanks for the feedback. Peter, I have forwarded your response to our ICT division to see if there is anything they can do.
> 
> One potentially silly question: what would happen if I had the help files loaded locally on my PC - would the call then work? I'm wondering about the wisdom of creating a proper directory structure, empty apart from the help files, on my local PC.

R generates the help pages on demand.  You can tell it what port to use, 
but it's not very easy to generate fixed copies of the HTML output.

Duncan Murdoch

> 
> Cheers
> Michelle
> 
> 
> -----Original Message-----
> From: Peter Dalgaard [mailto:pdalgd at gmail.com] 
> Sent: Friday, 10 September 2010 6:19 p.m.
> To: David Winsemius
> Cc: Gosse, Michelle; 'R-help at r-project.org'
> Subject: Re: [R] URL error when trying to use help function in R [Sec: UNOFFICIAL]
> 
> On 09/10/2010 01:03 AM, David Winsemius wrote:
>> On Sep 9, 2010, at 6:34 PM, Gosse, Michelle wrote:
>>
>>> Greetings,
>>>
>>> I am using R version 2.11.1 on a Dell computer, via a VMware  
>>> connection to a remote server. My browser version is IE  
>>> 8.0.6001.18702 and the OS is some corporate version of Microsoft XP.
>>>
>>> I'm trying to learn more about the tapply function , so I typed ? 
>>> tapply into the command line. This opened up a browser window with  
>>> url http://127.0.0.1:28138/library/base/html/tapply.html which is  
>>> giving me an error message.
>>> I receive the same problem when trying for help on other commands,  
>>> e.g. ?table http://127.0.0.1:28138/library/base/html/table.html and ? 
>>> log http://127.0.0.1:28138/library/base/html/Log.html
>>>
>>> I did a whois on 127.0.0.1
>> That should always be your own computer. The browser is trying to  
>> reach a server on itself over port 28138 and either the port is  
>> blocked or you don't have the documentation at that location.
> 
> The _real_ problem is likely that the server is really running on the
> remote computer. Substituting the remote server name for 127.0.0.1 is
> not unlikely to make things work. (Notwithstanding firewalls and the like).
> 
> It is a generic weakness of our current dynamic HTML setup, or of
> current browser technology if you like. Same thing with file:// URLs --
> if you try to view them in a browser and you already have a browser on
> your display, but running on a different machine than the one with the
> file, you get a "file not found". So when R on machine B wants to
> display a help page, it sends a message to the browser to connect to R's
> own server on B  by specifying a port on localhost (127.0.0.1), but if
> this request gets forwarded to a browser on machine A, then it goes
> looking for a server on _its_ localhost, i.e. machine A, and it isn't
> there...
> 
> I suppose we could do somewhat better, but I don't feel too confident
> about the various platform issues. As far as I can see, we currently
> hardcode "http://127.0.0.1" inside the help print method in
> utils:::print.help_file_with_topics(), and I suspect we could make that
> a user option, or try to be more intelligent about finding the machine's
> own IP address.
> 
> A pragmatic way out is always options(help_type="text").
> 
>