[VuFind-Tech] AJAX issues? Plus, Microsoft IE cache-ing issues?

[Chris D. <ce...@ui...>]

Hi all,

I am experiencing a major performance problem with the AJAX calls in
the Search Results screen:

Since there are quite a few (20 each) calls to getStatus() and
getSaveStatus(), I noticed that it took too long before a call to
getNarrowOptions() was made.  And since the narrowing functionality,
in my case, is the most time-consuming process, the effects of this
are disastrous.  I do realize that each call is asynchronous, however,
it appears that the relatively quick getStatus() and getSaveStatus()
responses are getting handled midstream, delaying the final call to
getNarrowOptions().  Viewing my apache logs (attached to this email)
will make this clear, I think.

I was able to solve my issue by queuing the getStatus() and
getSaveStatus() function calls and executing them at the end of the
page load (I didn't queue the getNarrowOptions() call).  I'm not sure
if this is the best way to handle it, but I didn't want to depend on
the layout of my web page to determine the order of execution.  At the
end of my apache log is the "queued" version of AJAX calls.  Notice
the difference in placement of getNarrowOptions().  BTW, I tested this
with Firefox 2.0.0.6 on Ubuntu Linux and also with Microsoft IE
version 6.0 on Windows 2000; they both had very similar behaviors.
Let me know if anyone is interested in my "fix."  In my particular
case, the usability of this page has increased significantly.

I also noticed a caching problem in Microsoft IE (version 6):

While testing with IE, I noticed the getStatus() calls were being
cached in the browser (with default IE cache settings set to
"Automatic").  Shouldn't these web pages be delivered with a no-cache
pragma (cache-control header)?  Because if they aren't, won't the
circulation information, i.e., availability, be potentially out of
date?  I verified this in my implementation of VUFind: I performed a
search, chose an item, then checked-out the item (rendering it
"unavailable"); I performed the same search again and the status
remained "available" (however, if I clicked on the Holdings in the
Record display, it correctly showed the proper circulation
information, i.e., "checked out").  I haven't yet attempted to address
this issue.  It may be as simple as modifying the launch() method in
web/services/Search/AJAX.php by adding an appropriate header and/or
pragma?

I am very interested in knowing if others are also sharing these
behaviors (or not).  Also, if anyone has suggestions on any of these
issues, I would greatly appreciate it!

Thanks!
Chris