[R] Closing FTP sessions with RCurl

[William Dunlap]

>With the call to gc(), the garbage collector will be called some time in
the
>future and the finalizers will be run then.

Typo: that initial 'With' should be 'Without'.


Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Wed, Jun 15, 2016 at 12:57 PM, William Dunlap <wdunlap at tibco.com> wrote:

> >>    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]]
>> >>
>> >> ______________________________________________
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>> >> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> >> and provide commented, minimal, self-contained, reproducible code.
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
>
>
>

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