Ben Lu Ben Lu - 6 months ago 16
iOS Question

Get partial errors from NSError

When using CloudKit, sometimes the error returned is

PartialFailure
, which may caused by duplicate subscriptions, etc. See example below.

<CKError 0x7f8318711520: "Partial Failure" (2/1011);
"Failed to modify some subscriptions"; uuid = A434B010-7650-4BBA-8A7A-33CD0690FD15;
container ID = "iCloud.xxx.xxx"; partial errors: {
EFC65F4A-A595-44A3-A022-323D9CE9B535 = <CKError 0x7f831a007be0: "Server Rejected Request" (15/2032); server message = "subscription is duplicate of '_930081460_AA87A676-DE57-4530-8BB8-7465BF4F4303'">
C4913907-28F3-42DB-8455-9966D9084834 = <CKError 0x7f83185cfc20: "Server Rejected Request" (15/2032); server message = "subscription is duplicate of '_930081460_F92FA91D-3E92-4E46-AE59-E912F8871026'"> }>


I wish to retrieve these partial errors from the main error object but I don't know how.
NSError
doesn't have a
partialError
property, and it neither has a key in
userInfo
to retrieve that.

Answer

You aren't getting back a straight NSError, you are getting back a CKError. Looking at the documentation for CKError, there is in fact a CKPartialErrorsByItemIDKey key. That looks like the key that would return a dictionary of CKErrors keyed by item ID if you ask me! The userInfo object should contain that key.

Also documented here

CloudKit Framework Constants Reference