URL download and Cache problems
alex at tweedly.net
Wed Dec 15 18:33:40 EST 2004
At 12:59 15/12/2004 -0800, Richard Gaskin wrote:
>This conversation raises a question -
>There are currently two ways to download files, the "load" command and
3 if you count libURLDownloadToFile (though it's for ftp only)
>It used to be the case that "load" was a better option for longer
>downloads and/or if you need to update a progress bar, since it was the
>only one of the two that was non-blocking and you could querty the
>urlStatus for those downloads.
>But now that we have the libUrlStatusCallback option, which provides
>periodic messages for "get URL", is there any benefit to using "load"?
Yes, lots of them (I think).
libURLSetStatusCallback provides you with periodic callbacks during
(amongst other things) a
get URL ....
command. However, it would be a bit convoluted to carry on and do other
processing from within such a callback; updating a progress bar/field would
be fine, but going on to do more than that feels a bit complicated.
Using load allows you to carry on with other general purpose processing of
any kind, while still providing both periodic callbacks AND "when complete"
Also (if I read the docs correctly - haven't tried it), you cannot initiate
a second blocking operation while the first one is still in progress (docs
say this results in an error "Error Previous request not completed"). If
you want to retrieve a number of URLs in parallel, the load command is
still the only way.
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