On 3/7/23 19:49, Thomas Lamprecht wrote:
Am 06/03/2023 um 15:03 schrieb Friedrich Weber:
Some UI components use `Ext.data.Store.setProxy` to change their
associated API endpoint URL in reaction to user input. One example is
`BackupView`, which calls `setProxy` when the user switches from
listing backups on storage A to listing backups on storage B. However,
if A is slow, the UI may receive the response for A *after* the
response for B. It will then display the contents of A as if they were
the contents of B, resulting in a UI inconsistency.
The reason is that `Ext.data.Store` still processes the slow response
for A, even though it is obsolete. This patch overrides the
responsible callback of `Ext.data.Store` to only process responses
belonging to the currently active proxy object. This should rule out
similar race conditions in all components that use the `setProxy` API.
In the above example, the patch results in the response for A being
ignored.
Ignored responses are logged to the browser console.
Note that this patch only concerns components that use `setProxy` for
changing API endpoints. Other components (e.g. those using
`proxy.setURL` for the same purpose) may be open to similar race
conditions.
Signed-off-by: Friedrich Weber <f.we...@proxmox.com>
---
The original report only concerns the backup view [1], where the race
condition is easy to trigger. While ruling out this particular race is
simple, I thought it would be worthwhile to rule out race condition of
this category for all components. Hence this patch. However, most of the
other races are much harder to trigger, so it may be questionable
whether a general fix is needed. So if wanted, I can alternatively
submit a patch that only fixes the backup view.
IMO a general fix/future proofing can be OK, so besides a small nit inline:
LGTM, but did not checked/tested this too closely - @Dominik, what do you
think on this?
This change is non-intrusive enough that it's OK, since it
fixes the reported issue and potentially some more.
When we're only fixing the one reported place, i guess
sooner or later someone else reports another instance of this,
and by then we probably forgot that we fixed it already once ;)
Really fixing all points where something like that can happen is
not easy since most of them are using Proxmox.Utils.API2Request
instead of a store, or as Friedrich already wrote, setting
the URL of the proxy manually, so this seems to be good
middle ground for now.
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