Maxime Petazzoni wrote:
Hi,
As I already said, the AJAX browser in mod_mbox relies on a hidden
XmlHttpRequest and on Javascript processing of the replied XML
document to generate the message list.
After setting up a browser stub, I'm not going to concentrate on
compatibility and speed problems before continuing. In fact, there are
two main problems implied by the current mechanism :
- On large mailboxes, the /ajax/msglist query reply can get *very*
large. As an example, this mailing list's 2001-08 archives contains
1708 messages, and the corresponding XML is 452492 bytes big. This
is too much. As a comparison, the old mod_mbox resulting page for
the same month is "only" 311 KB big.
As a solution to this, Ian advised the use of LiveGrid
(http://openrico.org/livegrid.page). It fetches only the piece of
data that need to be displayed (ten, twenty, ... rows instead of the
whole 1700+). I don't really like this solution because the user
must scroll the table, and then wait for the data to appear,
etc.
Isn't this where XmlHttpRequest comes in handy? Asynchronously fetch X (a hundred?) rows forward from where
the user is currently looking in anticipation that that user will scroll forward. So you don't slurp down the
whole mailbox at once, but you try to stay ahead of what the user might be expected to do and always have some
data ready to display.
And that we don't get the whole list (no in-page search for
example).
Another solution would be to use a page system as in the Debian
mailing list archives, displaying 100 or 200 messages per page
only. This would reduce bandwidth usage, but it will also make things
harder when updating the context box. For the moment, the message
list is fetched once, and all operations are made on this stored
list. When updating the context box, we just take -3 to +3 messages
from the list. With the page system, we'll experience problems while
approaching the end of a page ...
- The second problem is brought by the first one. On large mailboxes,
the Javascript processing takes too much time. Building all elements
each time the message list is displayed (at loading time or when you
close a message box) does not make the application usable.
Of course, the paging system would solve this problem, too. In
addition to this, my Javascript code may not be the most optimized
we could find.
- Concerning compatibility problems, the whole thing does not work
nor with IE, neither with Opera, although both of these browsers
does not comply against any javascript error.
Any JS compatibility expert in the house ?
Heh, you wish :0
This is a cool project, glad it's on the httpd dev list.
Bill
