Command Palette: Fix macOs label for sites unable to determine UA via PHP

[peterwilsoncc]

Adds a JavaScript check of the User-Agent for displaying the text in the admin bar.

On sites served over a CDN is it relatively common for the CDN to strip the User-Agent HTTP header, on macOS systems this causes the incorrect label to be displayed.

See WordPress/gutenberg#77636
Closes Core-65121

Testing Instructions

1. Buy a macOS computer/use BrowserStack on macOS.
2. In your wp-config.php file, add the code $_SERVER['HTTP_USER_AGENT'] = ''; to emulate a site behind a CDN stripping the header
3. Visit /wp-admin
4. Ensure the label is correct on this branch.
5. Ensure the label is incorrect on trunk
6. Remove the code added to the wp-config file to avoid confusion later.

Trac ticket: https://core.trac.wordpress.org/ticket/65121

Use of AI Tools

N/A

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Props peterwilsoncc, westonruter, mukesh27.

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[github-actions]

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[mukeshpanchal27]

1. Buy a macOS computer

😃

[peterwilsoncc]

@westonruter I've rewritten this based on the discussion on the ticket. I've also switched to navigator.platform for increased reliability over the UA sniffing.

[westonruter]

This is working well and I'm approving.

I did want to point out one thing which may improve maintenance going forward. Namely, a regular expression is being used on the User-Agent in PHP. This is not being used client-side. We could take that pattern from PHP and export it to JS for re-use, which would reduce the maintenance burden:

diff --git a/src/wp-includes/admin-bar.php b/src/wp-includes/admin-bar.php
index 1e96ac794d..c5e449a23c 100644
--- a/src/wp-includes/admin-bar.php
+++ b/src/wp-includes/admin-bar.php
@@ -953,7 +953,8 @@ function wp_admin_bar_command_palette_menu( WP_Admin_Bar $wp_admin_bar ): void {
 		'appleOS' => _x( '⌘K', 'keyboard shortcut to open the command palette' ),
 		'default' => _x( 'Ctrl+K', 'keyboard shortcut to open the command palette' ),
 	);
-	$is_apple_os     = (bool) preg_match( '/Macintosh|Mac OS X|Mac_PowerPC/i', $_SERVER['HTTP_USER_AGENT'] ?? '' );
+	$apple_pattern   = 'Macintosh|Mac OS X|Mac_PowerPC';
+	$is_apple_os     = (bool) preg_match( "/{$apple_pattern}/i", $_SERVER['HTTP_USER_AGENT'] ?? '' );
 	$shortcut_label  = $is_apple_os ? $shortcut_labels['appleOS'] : $shortcut_labels['default'];
 	$title           = sprintf(
 		'<span class="ab-icon" aria-hidden="true"></span><span class="ab-label"><kbd>%s</kbd><span class="screen-reader-text"> %s</span></span>',
@@ -969,15 +970,16 @@ function wp_admin_bar_command_palette_menu( WP_Admin_Bar $wp_admin_bar ): void {
 	 * wp-i18n to be loaded as a dependency.
 	 */
 	$function = <<<'JS'
-		( appleOSLabel ) => {
-			if ( navigator.platform.startsWith("Mac") || navigator.platform === "iPhone" || navigator.platform === "iPad" ) {
+		( applePattern, appleOSLabel ) => {
+			if ( ( new RegExp( applePattern ) ).test( navigator.userAgent ) ) {
 				document.querySelector( '#wp-admin-bar-command-palette .ab-label kbd' ).textContent = appleOSLabel;
 			}
 		}
 	JS;
 	$script   = sprintf(
-		'( %s )( %s );',
+		'( %s )( %s, %s );',
 		$function,
+		wp_json_encode( $apple_pattern, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES ),
 		wp_json_encode( $shortcut_labels['appleOS'], JSON_HEX_TAG | JSON_UNESCAPED_SLASHES )
 	);
 	$script  .= "\n//# sourceURL=" . rawurlencode( __FUNCTION__ );