X API OAuth Authorization fails on iPad WebView with unsupported browser error

[TakanoriSatou]

[Bug] X API OAuth Authorization fails on iPad WebView with unsupported browser error

Description

When attempting to use X (formerly Twitter) API OAuth authorization in Unity WebView on iPad, users encounter a browser compatibility error after pressing the login button.

Environment

• Unity WebView plugin: Latest master branch source code
• Platform: iPad only
• OS versions affected:
  • iPadOS 18.1.1 or later
  • iPadOS 17.7.2 or later
• User-Agent: Default (no specific configuration)

Steps to Reproduce

1. Open WebView in the application
2. Initiate X API OAuth flow using "oauth/authorize" endpoint
3. Press the login button on X's authorization page

Current Behavior

After pressing the login button, X displays an error page with the following messages:

• "このブラウザは現在サポートされていません。" (Japanese)
• "Please switch to a supported browser to continue using x.com. You can see a list of supported browser in our Help Center."

Expected Behavior

The OAuth authorization should complete successfully, allowing users to connect their X account.

Additional Information

• Issue can be reproduced with the latest master branch of the plugin
• The error page redirects to X's browser compatibility help page: https://help.x.com/ja/using-x/x-supported-browsers
• This issue appears to be iPad-specific; no similar issues observed on other platforms
• No custom User-Agent has been specified in WebView configuration
  

Questions

1. Is there a way to modify the WebView user agent or configuration to make it compatible with X's OAuth flow?
2. Are there any known workarounds for this issue on iPad?
3. Are there any specific User-Agent settings recommended for X OAuth authorization?

Any assistance or insights would be greatly appreciated.

[KojiNakamaru]

The issue could be solved by specifying wkContentMode to 1.

unity-webview/sample/Assets/Scripts/SampleWebView.cs

Line 126 in 3aa60f0

//wkContentMode: 0, // 0: recommended, 1: mobile, 2: desktop

Alternatively, specifying ua could be the only way.

unity-webview/sample/Assets/Scripts/SampleWebView.cs

Line 120 in 3aa60f0

//ua: "custom user agent string",

NOTE: Utilizing WebView for OAuth is generally not recommended and Google prohibits it for their platform.

[TakanoriSatou]

@KojiNakamaru
Thank you for the solutions and advice.

Setting wkContentMode to 1 resolved the issue as suggested.

I understand the security concerns regarding WebView OAuth authentication and will take this into consideration.

I'm closing this issue as the problem has been resolved.