asynchronous - Synchronization when implementing push , iOS -

i have special problem of synchronization application share , ideas me solve it.

i developing application 2 things :

1) registers push notifications in appdelegate .

2) opens webview in viewcontroller , loads url. form of url loaded : http://.www.thisismyurl.com/udid , udid users unique identifier.

in didregisterforremotenotificationswithdevicetoken: registering token , after receive , inside function make http request server send push token , udid.

so in both didregisterforremotenotificationswithdevicetoken of appdelegate , in viewcontroller retrieving udid , using described.

everything till last week worked perfectly. apple decided reject application using udid. way go me create unique identifier using cfuuid , save key chain.

the problem :

as see make use of unique identifier both in appdelegate's didregisterforremotenotificationswithdevicetoken function inside viewcontroller. must created in 1 of these controllers or else different!!! (remember cfuuid string created udid + datentime).

where should create ??? didregisterforremotenotificationswithdevicetoken asynchronous if retrieve there , viewcontroller make http request long before unique identifier reaches there , use null instead. same case happen viewcontroller. if try create there , maybe didregisterforremotenotificationswithdevicetoken function called faster , try register in database null unique identifier .

so can try create cfuuid string , sure controllers on time?

edit

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an idea came on top of head. if created cfuuid inside didfinishlaunchingwithoptions function of appdelegate ?? if not mistaken part of code run first , before else. there wont synchronization problem ll pass safely everywhere need it. right?

as said, didfinishlaunchingwithoptions first method executed when application launched.

if create cfuuid @ beginning of method, before registering push notifications, have value when receive device token apple (when didregisterforremotenotificationswithdevicetoken called), , have value time open webview.