iOS 12.0 Beta 1 WKWebview cross origin requests fail - Preflight response is not successful

Originator:joel.kennedy
Number:rdar://40807782 Date Originated:05/06/2018
Status:Open Resolved:
Product:iOS Product Version:12.0 Beta 1
Classification: Reproducible:Always
 
In iOS 12.0 Beta 1, Ajax cross origin requests are failing from WKWebview with the error "Preflight response is not successful. XMLHttpRequest cannot load [url omitted] due to access control checks". This happens even when the remote server is setting "Access-Control-Allow-Origin: *" as a response header.

Steps to Reproduce: Make an Ajax cross origin request from a page running inside WKWebview being served off localhost on a device running iOS 12. Ensure the server being connected to is returning a "Access-Control-Allow-Origin: *" header.

Expected Results: The request should succeed.

Actual Results: The request fails with an error in console: "Preflight response is not successful. XMLHttpRequest cannot load [url omitted] due to access control checks".

Comments

Regression?

I'm having this problem with iOS 12 now - see https://stackoverflow.com/questions/52434011/how-to-fix-ios-12-safari-cors-preflight-error?noredirect=1#comment91847506_52434011

I've reported it here https://bugreport.apple.com/web/?problemID=44621834

and it is duped here https://bugreport.apple.com/web/?problemID=42546319

but I cannot see that ticket

By user1gguser1gg at Sept. 24, 2018, 1:45 p.m. (reply...)

It look like Xcode 10 beta 2 respectively iOS 12 beta 2 solves the issue...it deserves a try

By flusterfluster at June 19, 2018, 9:05 p.m. (reply...)

Yes, in iOS 12 Beta 2 this is fixed.

By fassko at June 20, 2018, 5:59 a.m. (reply...)

I have the same issue with WKWebView and iOS 12 Beta 1.

By fassko at June 19, 2018, 10:04 a.m. (reply...)

Hi there! Seeing this as well in a bunch of other apps. We're currently tracking this in Ionic here https://github.com/ionic-team/cordova-plugin-ionic-webview/issues/112

Seems to be specific to WKWebview

By mikehartington at June 11, 2018, 4:13 p.m. (reply...)

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