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 for A, even though it is obsolete.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? > > Also, there are several occurrences of the `proxy.setURL` or `proxy.url = > ...` > patterns (see [1]) which are also susceptible to race conditions, and which > are not fixed by this patch. However, for those, I have not found a nice > solution that does not involve changing a lot of call sites. If wanted, I can > give it another try, or alternatively only submit patches for components for > which triggering the race conditions seems realistic. > > [1] https://bugzilla.proxmox.com/show_bug.cgi?id=4421 > > src/Utils.js | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/src/Utils.js b/src/Utils.js > index f55b9a5..8a97487 100644 > --- a/src/Utils.js > +++ b/src/Utils.js > @@ -1451,3 +1451,18 @@ Ext.define('Proxmox.Async', { > return new Promise((resolve, _reject) => setTimeout(resolve, millis)); > }, > }); > + > +Ext.override(Ext.data.Store, { > + // If the store's proxy is changed while it is waiting for an AJAX > + // response, `onProxyLoad` will still be called for the outdated > response. > + // To avoid displaying inconsistent information, only process responses > + // belonging to the current proxy. > + onProxyLoad: function(operation) { > + let me = this; > + if (operation.getProxy() === me.getProxy()) { > + me.callParent(arguments); > + } else { > + console.log(`ignored outdated response: > ${operation.getRequest().getUrl()}`); maybe warn? also, no need to interpolate text on the console helpers, just add as it's own param, which often gives a much better dev experience (as object can then be inspected in full) - here it's just an URL (maybe dump the full thing?), so YNNV. console.warn('ignored outdated response:', operation.getRequest().getUrl()); > + } > + }, > +}); _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
