Closing FTP sessions with RCurl

With the call to gc(), the garbage collector will be called some time in

future and the finalizers will be run then.

   rm(curl) # release the curl! (does this end the session???)

Try adding a call to gc() immediately after this removal.  That will force
an
immediate run of any finalizer associated with the object just removed.
With the call to gc(), the garbage collector will be called some time in
the
future and the finalizers will be run then.

(I don't know if curl has a finalizer that closes the session.)


Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Wed, Jun 15, 2016 at 12:34 PM, J Payne <jcpayne at uw.edu> wrote:

Thanks Tom!  I tried that and it didn?t work, but perhaps there are other
problems.  The system administrator wrote ?I think closing sessions
immediately upon completion of the transfer,
or continuing to use the same session for additional requests would both
have a similar and positive effect.?  However, I?ve now tried your solution
to close the session, and also tried using one curl handle throughout, but
the throttling persists.

John

On 6/14/16, 1:00 PM, "Tom Wright" <tom at maladmin.com> wrote:

No expert here, and this isn't tested. It seems you can set the
forbid.reuse option which will cause curl to shutdown the connection
after transfer is complete.

if(url.exists("http://www.omegahat.net/RCurl/index.html")) {
  curl <- getCurlHandle()
  curlSetOpt(.opts=list(forbid.reuse=1),curl=curl)
  getURL("http://www.omegahat.net/RCurl/index.html", curl = curl)
}

On Tue, Jun 14, 2016 at 2:41 PM, J Payne <jcpayne at uw.edu> wrote:

Does anyone know how to close an FTP session with RCurl?  I am trying

to automate the process of downloading snow data from a government website,
and their server is throttling the connection after a few files are
downloaded.  I contacted their system administrator, who wrote: ?My
suspicion at this point is that the getURL commands are opened and perform
the function asked, then linger in wait for 15 minutes until or ftp server
closes the idle sessions. Is there a way to tell R to close the sessions??

I?ve perused the RCurl manual but I don?t see a way to close

sessions.  I tried copying the following example from the RCurl manual, but
it didn?t solve the problem.  I?m a novice at this and I don?t understand
the relationship between handles and sessions, so I am probably missing
something.

#EXAMPLE from getCurl(), p. 39

if(url.exists("http://www.omegahat.net/RCurl/index.html")) {

   curl = getCurlHandle()

   getURL("http://www.omegahat.net/RCurl/index.html", curl = curl)

   #getCurlInfo(curl) # I skipped this step

   rm(curl) # release the curl! (does this end the session???)

}



Thanks!



John


        [[alternative HTML version deleted]]