Unexpected system confirmation dialog when opening a Universal Link

Thank you for your post. Very interesting. Your observation regarding the behavior of Universal Links on iOS, where the app opens automatically in some instances but prompts a confirmation dialog in others, is intentional and aligns with iOS’s security and user experience considerations.

Apple implemented this confirmation mechanism partially due to security concerns. While this behavior is designed to enhance security and user control, Universal Links requires proper configuration of Apple-app-site-association files and associated domains. It is recommended to verify configurations using Apple’s validation tools to identify and resolve any technical inconsistencies. For more information, please refer to the following document: TN3155: Debugging universal links | Apple Developer Documentation

In my opinion, best practices for Universal Links and redirect handling should be adopted to optimize user experiences as much as possible. Oh remember the iOS will also remembers how the user want to handle each link.

Albert Pascual
  Worldwide Developer Relations.

We did follow the debugging guide.

The issue here is to understand why it works correctly the first time, meaning that the Apple-app-site-association files and associated domains are configured correctly, and not the second time while remaining on the same tab.

We need help understanding what the security difference is between the first invocation and second knowing that it is the exact same website executed and javascript code executed on both attempts.

Any update on this @DTS Engineer ? We are currently stuck in making progress on this issue. We'd appreciate guidance on what to do to avoid such behavior. As explained, we believe our Universal link are configured correctly since App switch works correctly initially.

Thank you for your response and for taking the time to read the Technical Note. I believe you have now realized that Universal Links function consistently well, but there could be several reasons for their behavior deviating from expectations:

When encountering issues related to Apple-app-site-association files and associated domains, particularly when they function correctly on the first attempt but fail on subsequent attempts within the same tab, several potential security and configuration factors could be at play:

• JavaScript Logic Errors:
  • Although you mentioned that the code execution is identical, race conditions or state mismanagement within your JavaScript could lead to differing outcomes on successive runs. Please verify for such possibilities.
• Error Handling and Logs:
  • Enhance error handling surrounding the associated domain validation logic and ensure comprehensive logging to capture any discrepancies during the second invocation.

By systematically examining these areas, you should be able to identify discrepancies causing the differing behavior on subsequent invocations within the same tab.

I would recommend to follow the guidelines to just create a link following the Universal Links specification.

https://developer.apple.com/documentation/xcode/supporting-universal-links-in-your-app

You can always look at the sysdiagnose sw_util file to see how was handled as shown on the Tech Note.

You can always provide me the app for me to go over the Tech Note troubleshooting to find the issue of your javascript.

Will it work without javascript?

Albert Pascual
  Worldwide Developer Relations.