[web] Resolve OS as iOs for iDevice Safari requesting desktop version of app. (#25957)

lib/web_ui/lib/src/engine/browser_detection.dart

@@ -131,7 +131,7 @@ enum OperatingSystem {
 }
 
 /// Lazily initialized current operating system.
-late final OperatingSystem _operatingSystem = _detectOperatingSystem();
+late final OperatingSystem _operatingSystem = detectOperatingSystem();
 
 /// Returns the [OperatingSystem] the current browsers works on.
 ///
@@ -149,11 +149,23 @@ OperatingSystem get operatingSystem {
 /// This is intended to be used for testing and debugging only.
 OperatingSystem? debugOperatingSystemOverride;
 
-OperatingSystem _detectOperatingSystem() {
-  final String platform = html.window.navigator.platform!;
-  final String userAgent = html.window.navigator.userAgent;
+@visibleForTesting
+OperatingSystem detectOperatingSystem({
+  String? overridePlatform,
+  String? overrideUserAgent,
+  int? overrideMaxTouchPoints,
+}) {
+  final String platform = overridePlatform ?? html.window.navigator.platform!;
+  final String userAgent = overrideUserAgent ?? html.window.navigator.userAgent;
 
   if (platform.startsWith('Mac')) {
+    // iDevices requesting a "desktop site" spoof their UA so it looks like a Mac.
+    // This checks if we're in a touch device, or on a real mac.
+    final int maxTouchPoints =
+        overrideMaxTouchPoints ?? html.window.navigator.maxTouchPoints ?? 0;
+    if (maxTouchPoints > 2) {
+      return OperatingSystem.iOs;
+    }
     return OperatingSystem.macOs;
   } else if (platform.toLowerCase().contains('iphone') ||
       platform.toLowerCase().contains('ipad') ||

lib/web_ui/test/browser_detect_test.dart

@@ -11,38 +11,154 @@ void main() {
 }
 
 void testMain() {
-  test('Should detect Blink', () {
-    // Chrome Version 89.0.4389.90 (Official Build) (x86_64) / MacOS
-    BrowserEngine browserEngine = detectBrowserEngineByVendorAgent(
-        'Google Inc.',
-        'mozilla/5.0 (macintosh; intel mac os x 11_2_3) applewebkit/537.36 '
-        '(khtml, like gecko) chrome/89.0.4389.90 safari/537.36');
-    expect(browserEngine, BrowserEngine.blink);
-  });
+  group('detectBrowserEngineByVendorAgent', () {
+    test('Should detect Blink', () {
+      // Chrome Version 89.0.4389.90 (Official Build) (x86_64) / MacOS
+      BrowserEngine browserEngine = detectBrowserEngineByVendorAgent(
+          'Google Inc.',
+          'mozilla/5.0 (macintosh; intel mac os x 11_2_3) applewebkit/537.36 '
+              '(khtml, like gecko) chrome/89.0.4389.90 safari/537.36');
+      expect(browserEngine, BrowserEngine.blink);
+    });
 
-  test('Should detect Firefox', () {
-    // 85.0.2 (64-bit) / MacOS
-    BrowserEngine browserEngine = detectBrowserEngineByVendorAgent(
-        '',
-        'mozilla/5.0 (macintosh; intel mac os x 10.16; rv:85.0) '
-        'gecko/20100101 firefox/85.0');
-    expect(browserEngine, BrowserEngine.firefox);
-  });
+    test('Should detect Firefox', () {
+      // 85.0.2 (64-bit) / MacOS
+      BrowserEngine browserEngine = detectBrowserEngineByVendorAgent(
+          '',
+          'mozilla/5.0 (macintosh; intel mac os x 10.16; rv:85.0) '
+              'gecko/20100101 firefox/85.0');
+      expect(browserEngine, BrowserEngine.firefox);
+    });
+
+    test('Should detect Safari', () {
+      BrowserEngine browserEngine = detectBrowserEngineByVendorAgent(
+          'Apple Computer, Inc.',
+          'mozilla/5.0 (macintosh; intel mac os x 10_15_6) applewebkit/605.1.15 '
+              '(khtml, like gecko) version/14.0.3 safari/605.1.15');
+      expect(browserEngine, BrowserEngine.webkit);
+    });
 
-  test('Should detect Safari', () {
-    BrowserEngine browserEngine = detectBrowserEngineByVendorAgent(
-      'Apple Computer, Inc.',
-      'mozilla/5.0 (macintosh; intel mac os x 10_15_6) applewebkit/605.1.15 '
-      '(khtml, like gecko) version/14.0.3 safari/605.1.15');
-    expect(browserEngine, BrowserEngine.webkit);
+    test('Should detect Samsung browser', () {
+      // Samsung 13.2.1.70 on Galaxy Tab S6.
+      BrowserEngine browserEngine = detectBrowserEngineByVendorAgent(
+          'Google Inc.',
+          'mozilla/5.0 (x11; linux x86_64) applewebkit/537.36 (khtml, like gecko)'
+              ' samsungbrowser/13.2 chrome/83.0.4103.106 safari/537.36');
+      expect(browserEngine, BrowserEngine.samsung);
+    });
   });
 
-  test('Should detect Samsung browser', () {
-    // Samsung 13.2.1.70 on Galaxy Tab S6.
-    BrowserEngine browserEngine = detectBrowserEngineByVendorAgent(
-        'Google Inc.',
-        'mozilla/5.0 (x11; linux x86_64) applewebkit/537.36 (khtml, like gecko)'
-        ' samsungbrowser/13.2 chrome/83.0.4103.106 safari/537.36');
-    expect(browserEngine, BrowserEngine.samsung);
+  group('detectOperatingSystem', () {
+    void expectOs(
+      OperatingSystem expectedOs, {
+      String platform = 'any',
+      String ua = 'any',
+      int touchPoints = 0,
+    }) {
+      expect(
+          detectOperatingSystem(
+            overridePlatform: platform,
+            overrideUserAgent: ua,
+            overrideMaxTouchPoints: touchPoints,
+          ),
+          expectedOs);
+    }
+
+    test('Determine unknown for weird values of platform/ua', () {
+      expectOs(OperatingSystem.unknown);
+    });
+
+    test('Determine MacOS if platform starts by Mac', () {
+      expectOs(
+        OperatingSystem.macOs,
+        platform: 'MacIntel',
+      );
+      expectOs(
+        OperatingSystem.macOs,
+        platform: 'MacAnythingElse',
+      );
+    });
+
+    test('Determine iOS if platform contains iPhone/iPad/iPod', () {
+      expectOs(
+        OperatingSystem.iOs,
+        platform: 'iPhone',
+      );
+      expectOs(
+        OperatingSystem.iOs,
+        platform: 'iPhone Simulator',
+      );
+      expectOs(
+        OperatingSystem.iOs,
+        platform: 'iPad',
+      );
+      expectOs(
+        OperatingSystem.iOs,
+        platform: 'iPad Simulator',
+      );
+      expectOs(
+        OperatingSystem.iOs,
+        platform: 'iPod',
+      );
+      expectOs(
+        OperatingSystem.iOs,
+        platform: 'iPod Simulator',
+      );
+    });
+
+    // See https://github.com/flutter/flutter/issues/81918
+    test('Tell apart MacOS from iOS requesting a desktop site.', () {
+      expectOs(
+        OperatingSystem.macOs,
+        platform: 'MacARM',
+      );
+
+      expectOs(
+        OperatingSystem.iOs,
+        platform: 'MacARM',
+        touchPoints: 5,
+      );
+    });
+
+    test('Determine Android if user agent contains Android', () {
+      expectOs(
+        OperatingSystem.android,
+        ua: 'Mozilla/5.0 (Linux; U; Android 2.2) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1',
+      );
+    });
+
+    test('Determine Linux if the platform begins with Linux', () {
+      expectOs(
+        OperatingSystem.linux,
+        platform: 'Linux',
+      );
+      expectOs(
+        OperatingSystem.linux,
+        platform: 'Linux armv8l',
+      );
+      expectOs(
+        OperatingSystem.linux,
+        platform: 'Linux x86_64',
+      );
+    });
+
+    test('Determine Windows if the platform begins with Win', () {
+      expectOs(
+        OperatingSystem.windows,
+        platform: 'Windows',
+      );
+      expectOs(
+        OperatingSystem.windows,
+        platform: 'Win32',
+      );
+      expectOs(
+        OperatingSystem.windows,
+        platform: 'Win16',
+      );
+      expectOs(
+        OperatingSystem.windows,
+        platform: 'WinCE',
+      );
+    });
   });
 }