R help - Jul 2012 - check whether connection can be opened

Hi all,

I'm working on a function that reads online data that is only available to
certain IPs. It then writes a subset of the data into a file.
So whenever I'm logged in elsewhere or am not connected to the internet, I
get an error, and the function is terminated.
I want it to rather print a message into the file.

Is there any way to test whether a connection can be opened?
Analogous to isOpen something like canOpen...
Or would I want to look into the error handling options?

By the way, the data is the internet volume used so far, which I want to track
regularly (on every R-Start via Rprofile).
My brother (a computer schientist in progress) did not know a solution, so I set
out to try this with R - which I got to work fine (except the above mentioned).
"R beats java", I told him, to which he responded nothing ;-)
Isn't it amazing, what one can do with R?

Thanks ahead,
Berry Boessenkool

 		 	   		  
	[[alternative HTML version deleted]]

I think you'll need to roll your own using tryCatch() around open(). 

Michael

On Jul 18, 2012, at 5:09 AM, Berry Boessenkool <berryboessenkool at
hotmail.com> wrote:
> 
> 
> Hi all,
> 
> I'm working on a function that reads online data that is only available
to certain IPs. It then writes a subset of the data into a file.
> So whenever I'm logged in elsewhere or am not connected to the
internet, I get an error, and the function is terminated.
> I want it to rather print a message into the file.
> 
> Is there any way to test whether a connection can be opened?
> Analogous to isOpen something like canOpen...
> Or would I want to look into the error handling options?
> 
> By the way, the data is the internet volume used so far, which I want to
track regularly (on every R-Start via Rprofile).
> My brother (a computer schientist in progress) did not know a solution, so
I set out to try this with R - which I got to work fine (except the above
mentioned).
> "R beats java", I told him, to which he responded nothing ;-)
> Isn't it amazing, what one can do with R?
> 
> Thanks ahead,
> Berry Boessenkool
> 
>                         
>    [[alternative HTML version deleted]]
> 
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