Falls back to using remote font urls if uploading is not allowed

lib/compat/wordpress-6.5/fonts/class-wp-rest-font-faces-controller.php

@@ -326,6 +326,14 @@ public function create_item( $request ) {
 			$settings    = $request->get_param( 'font_face_settings' );
 			$file_params = $request->get_file_params();
 
+			if ( ! empty( $file_params ) && ! $this->can_upload_fonts() ) {
+				return new WP_Error(
+					'rest_cannot_upload_fonts',
+					__( 'You are not allowed to upload font files.', 'gutenberg' ),
+					array( 'status' => 403 )
+				);
+			}
+
 			// Check that the necessary font face properties are unique.
 			$query = new WP_Query(
 				array(
@@ -903,6 +911,18 @@ public function handle_font_file_upload_error( $file, $message ) {
 			return new WP_Error( $code, $message, array( 'status' => $status ) );
 		}
 
+		/**
+		 * Checks if fonts can be uploaded to the site.
+		 *
+		 * @since 6.5.0
+		 *
+		 * @return bool Whether font assets can be upload.
+		 */
+		protected function can_upload_fonts() {
+			$fonts_dir = wp_get_font_dir()['path'];
+			return wp_is_file_mod_allowed( 'can_upload_fonts' ) && wp_is_writable( $fonts_dir );
+		}
+
 		/**
 		* Returns relative path to an uploaded font file.
 		*

packages/edit-site/src/components/global-styles/font-library-modal/font-collection.js

@@ -23,6 +23,8 @@ import {
 import { debounce } from '@wordpress/compose';
 import { sprintf, __, _x } from '@wordpress/i18n';
 import { search, closeSmall } from '@wordpress/icons';
+import { store as editorStore } from '@wordpress/editor';
+import { useSelect } from '@wordpress/data';
 
 /**
  * Internal dependencies
@@ -161,13 +163,13 @@ function FontCollection( { slug } ) {
 		setFontsToInstall( [] );
 	};
 
-	const handleInstall = async () => {
+	const handleInstall = async ( shouldUpload = true ) => {
 		setNotice( null );
 
 		const fontFamily = fontsToInstall[ 0 ];
 
 		try {
-			if ( fontFamily?.fontFace ) {
+			if ( fontFamily?.fontFace && shouldUpload ) {
 				await Promise.all(
 					fontFamily.fontFace.map( async ( fontFace ) => {
 						if ( fontFace.src ) {
@@ -398,12 +400,17 @@ function PaginationFooter( { page, totalPages, setPage } ) {
 
 function InstallFooter( { handleInstall, isDisabled } ) {
 	const { isInstalling } = useContext( FontLibraryContext );
+	const fontUploadEnabled = useSelect(
+		( select ) =>
+			select( editorStore ).getEditorSettings().fontUploadEnabled,
+		[]
+	);
 
 	return (
 		<Flex justify="flex-end">
 			<Button
 				variant="primary"
-				onClick={ handleInstall }
+				onClick={ () => handleInstall( fontUploadEnabled ) }
 				isBusy={ isInstalling }
 				disabled={ isDisabled || isInstalling }
 				__experimentalIsFocusable