I have a problem with the URL schemes under iOS 18. Data is being sent from one app to another app. The amount of data varies. It can sometimes be more than 5 MB.
With iOS 18, errors often occur when sending large amounts of data. The error message is: "Failed to open URL asynchronously". If I send the data once again in this case, it works.
To reproduce the error quickly, I wrote two small apps. AppA sends data to AppB. AppB calls AppA and AppA sends data to AppB again. The whole thing runs in an endless loop.
Code snippet:
// AppA
// The file to which fileUrl points contains a 4 MB string.
// The string consists of only one letter “AAAAAA....”
let dataStr = try String(contentsOf: fileUrl, encoding: .utf8)
if let url = URL(string: "appb://receive?data=\(dataStr)") {
UIApplication.shared.open(url, options: [:]) { (result) in
if !result {
os_log("can't open url", type: .error)
}
}
}
// AppB
DispatchQueue.main.asyncAfter(deadline: .now() + 2.0) {
if let returnUrl = URL(string: "appa://return") {
UIApplication.shared.open(returnUrl)
}
}
If the test is started, the error occurs approximately 15-20 times per hour.
The first error occurs very quickly if the device is restarted prior to this.
As soon as the error occurs, we end up in
os_log(“can't open url”, type: .error)
I know the possibility of exchanging the data via AppGroups, but cannot use it in our case.
Tested with following devices:
// The error occurs:
iPhone 11 with iOS 18.4.1
iPhone SE with iOS 18.5
// The error does not occur
iPhone 8 with iOS 16.7.10
iPhone 16 simulator on a M1 MacBook (macOS 15.4.1)
Unfortunately, there is no other error message in the "Console" app. Except "Failed to open URL asynchronously".
There were no problems at this point between iOS 12 and iOS 17.
My question is now, are there new limitations to the URL schemes under iOS 18 or is it a bug?
