Media: Expose image_strip_meta and image_max_bit_depth in the REST index.

When client-side media processing is active, image decoding, scaling, and encoding happen in the browser, so no server-side `WP_Image_Editor` is instantiated. As a result the `image_strip_meta` and `image_max_bit_depth` filters never influence generated images, and plugins relying on them have no effect on client-generated sub-sizes.

Expose the filtered values of both hooks on the REST API index inside the existing client-side media processing block in `WP_REST_Server::get_index()`, alongside the already-exported `image_size_threshold`, so the client encoder can honor them. The client-side consumption of these values ships via the Gutenberg package updates in WordPress/gutenberg#80218.

Props westonruter, soyebsalar01.
Fixes #65623.



git-svn-id: https://develop.svn.wordpress.org/trunk@62806 602fd350-edb4-49c9-b593-d223f7449a82

Author: adamsilverstein

src/wp-includes/rest-api/class-wp-rest-server.php

@@ -1384,6 +1384,20 @@ public function get_index( $request ) {
 
 			/** This filter is documented in wp-admin/includes/image.php */
 			$available['image_size_threshold'] = (int) apply_filters( 'big_image_size_threshold', 2560, array( 0, 0 ), '', 0 );
+
+			/** This filter is documented in wp-includes/class-wp-image-editor-imagick.php */
+			$available['image_strip_meta'] = (bool) apply_filters( 'image_strip_meta', true );
+
+			/*
+			 * On the server, this filter receives the decoded image's actual bit depth.
+			 * The client path never decodes the image on the server, so the filter is
+			 * applied with 16 (the maximum depth the client encoder can produce) as
+			 * both the value and the current depth. The client caps its output bit
+			 * depth at the filtered value, so a plugin lowering it (e.g. to 8) takes
+			 * effect on client-generated images too.
+			 */
+			/** This filter is documented in wp-includes/class-wp-image-editor-imagick.php */
+			$available['image_max_bit_depth'] = (int) apply_filters( 'image_max_bit_depth', 16, 16 );
 		}
 
 		$response = new WP_REST_Response( $available );

tests/phpunit/tests/rest-api/rest-server.php

@@ -1207,6 +1207,76 @@ public function test_get_index() {
 		$this->assertArrayHasKey( 'site_icon_url', $data );
 	}
 
+	/**
+	 * @ticket 64804
+	 *
+	 * @covers WP_REST_Server::get_index
+	 */
+	public function test_get_index_should_include_media_processing_settings(): void {
+		$user_id = self::factory()->user->create( array( 'role' => 'administrator' ) );
+		$this->assertIsInt( $user_id );
+		wp_set_current_user( $user_id );
+		add_filter( 'wp_client_side_media_processing_enabled', '__return_true' );
+
+		$server  = new WP_REST_Server();
+		$request = new WP_REST_Request( 'GET', '/' );
+		$index   = $server->dispatch( $request );
+		$data    = $index->get_data();
+		$this->assertIsArray( $data );
+
+		$this->assertArrayHasKey( 'image_sizes', $data );
+		$this->assertArrayHasKey( 'image_size_threshold', $data );
+		$this->assertArrayHasKey( 'image_strip_meta', $data );
+		$this->assertTrue( $data['image_strip_meta'] );
+		$this->assertArrayHasKey( 'image_max_bit_depth', $data );
+		$this->assertSame( 16, $data['image_max_bit_depth'] );
+	}
+
+	/**
+	 * @ticket 64804
+	 *
+	 * @covers WP_REST_Server::get_index
+	 */
+	public function test_get_index_should_not_include_media_processing_settings_without_caps(): void {
+		add_filter( 'wp_client_side_media_processing_enabled', '__return_true' );
+
+		$server  = new WP_REST_Server();
+		$request = new WP_REST_Request( 'GET', '/' );
+		$index   = $server->dispatch( $request );
+		$data    = $index->get_data();
+		$this->assertIsArray( $data );
+
+		$this->assertArrayNotHasKey( 'image_sizes', $data );
+		$this->assertArrayNotHasKey( 'image_size_threshold', $data );
+		$this->assertArrayNotHasKey( 'image_strip_meta', $data );
+		$this->assertArrayNotHasKey( 'image_max_bit_depth', $data );
+	}
+
+	/**
+	 * @ticket 64804
+	 *
+	 * @covers WP_REST_Server::get_index
+	 */
+	public function test_get_index_should_honor_media_processing_filters(): void {
+		$user_id = self::factory()->user->create( array( 'role' => 'administrator' ) );
+		$this->assertIsInt( $user_id );
+		wp_set_current_user( $user_id );
+		add_filter( 'wp_client_side_media_processing_enabled', '__return_true' );
+		add_filter( 'image_strip_meta', '__return_false' );
+		add_filter(
+			'image_max_bit_depth',
+			static fn ( int $max_depth ) => min( 8, $max_depth )
+		);
+
+		$server  = new WP_REST_Server();
+		$request = new WP_REST_Request( 'GET', '/' );
+		$index   = $server->dispatch( $request );
+		$data    = $index->get_data();
+
+		$this->assertFalse( $data['image_strip_meta'] );
+		$this->assertSame( 8, $data['image_max_bit_depth'] );
+	}
+
 	/**
 	 * @ticket 57902
 	 *

tests/qunit/fixtures/wp-api-generated.js

@@ -13061,6 +13061,8 @@ mockedApiResponse.Schema = {
         }
     },
     "image_size_threshold": 2560,
+    "image_strip_meta": true,
+    "image_max_bit_depth": 16,
     "site_logo": 0,
     "site_icon": 0,
     "site_icon_url": ""