Drag and drop: fix drop zones on block drag

packages/block-editor/src/components/inserter-draggable-blocks/index.js

@@ -2,12 +2,9 @@
  * WordPress dependencies
  */
 import { Draggable } from '@wordpress/components';
-import {
-	createBlock,
-	serialize,
-	store as blocksStore,
-} from '@wordpress/blocks';
+import { createBlock, store as blocksStore } from '@wordpress/blocks';
 import { useDispatch, useSelect } from '@wordpress/data';
+import { useMemo } from '@wordpress/element';
 
 /**
  * Internal dependencies
@@ -24,20 +21,6 @@ const InserterDraggableBlocks = ( {
 	children,
 	pattern,
 } ) => {
-	const transferData = {
-		type: 'inserter',
-		blocks,
-	};
-
-	const blocksContainMedia =
-		blocks.filter(
-			( block ) =>
-				( block.name === 'core/image' ||
-					block.name === 'core/audio' ||
-					block.name === 'core/video' ) &&
-				( block.attributes.url || block.attributes.src )
-		).length > 0;
-
 	const blockTypeIcon = useSelect(
 		( select ) => {
 			const { getBlockType } = select( blocksStore );
@@ -52,6 +35,13 @@ const InserterDraggableBlocks = ( {
 		useDispatch( blockEditorStore )
 	);
 
+	const patternBlock = useMemo( () => {
+		return pattern?.type === INSERTER_PATTERN_TYPES.user &&
+			pattern?.syncStatus !== 'unsynced'
+			? [ createBlock( 'core/block', { ref: pattern.id } ) ]
+			: undefined;
+	}, [ pattern ] );
+
 	if ( ! isEnabled ) {
 		return children( {
 			draggable: false,
@@ -60,21 +50,21 @@ const InserterDraggableBlocks = ( {
 		} );
 	}
 
+	const draggableBlocks = patternBlock ?? blocks;
 	return (
 		<Draggable
 			__experimentalTransferDataType="wp-blocks"
-			transferData={ transferData }
+			transferData={ { type: 'inserter', blocks: draggableBlocks } }
 			onDragStart={ ( event ) => {
 				startDragging();
-				const parsedBlocks =
-					pattern?.type === INSERTER_PATTERN_TYPES.user &&
-					pattern?.syncStatus !== 'unsynced'
-						? [ createBlock( 'core/block', { ref: pattern.id } ) ]
-						: blocks;
-				event.dataTransfer.setData(
-					blocksContainMedia ? 'default' : 'text/html',
-					serialize( parsedBlocks )
-				);
+				for ( const block of draggableBlocks ) {
+					const type = `wp-block:${ block.name }`;
+					// This will fill in the dataTransfer.types array so that
+					// the drop zone can check if the draggable is eligible.
+					// Unfortuantely, on drag start, we don't have access to the
+					// actual data, only the data keys/types.
+					event.dataTransfer.items.add( '', type );
+				}
 			} }
 			onDragEnd={ () => {
 				stopDragging();

packages/block-editor/src/components/media-placeholder/index.js

@@ -19,7 +19,6 @@ import { __ } from '@wordpress/i18n';
 import { useState, useEffect } from '@wordpress/element';
 import { useSelect } from '@wordpress/data';
 import { keyboardReturn } from '@wordpress/icons';
-import { pasteHandler } from '@wordpress/blocks';
 import deprecated from '@wordpress/deprecated';
 
 /**
@@ -29,6 +28,7 @@ import MediaUpload from '../media-upload';
 import MediaUploadCheck from '../media-upload/check';
 import URLPopover from '../url-popover';
 import { store as blockEditorStore } from '../../store';
+import { parseDropEvent } from '../use-on-block-drop';
 
 const noop = () => {};
 
@@ -229,30 +229,15 @@ export function MediaPlaceholder( {
 		} );
 	};
 
-	async function handleBlocksDrop( blocks ) {
-		if ( ! blocks || ! Array.isArray( blocks ) ) {
-			return;
-		}
+	async function handleBlocksDrop( event ) {
+		const { blocks } = parseDropEvent( event );
 
-		function recursivelyFindMediaFromBlocks( _blocks ) {
-			return _blocks.flatMap( ( block ) =>
-				( block.name === 'core/image' ||
-					block.name === 'core/audio' ||
-					block.name === 'core/video' ) &&
-				( block.attributes.url || block.attributes.src )
-					? [ block ]
-					: recursivelyFindMediaFromBlocks( block.innerBlocks )
-			);
-		}
-
-		const mediaBlocks = recursivelyFindMediaFromBlocks( blocks );
-
-		if ( ! mediaBlocks.length ) {
+		if ( ! blocks || ! blocks.length ) {
 			return;
 		}
 
 		const uploadedMediaList = await Promise.all(
-			mediaBlocks.map( ( block ) => {
+			blocks.map( ( block ) => {
 				const blockType = block.name.split( '/' )[ 1 ];
 				if ( block.attributes.id ) {
 					block.attributes.type = blockType;
@@ -292,13 +277,6 @@ export function MediaPlaceholder( {
 		}
 	}
 
-	async function onDrop( event ) {
-		const blocks = pasteHandler( {
-			HTML: event.dataTransfer?.getData( 'default' ),
-		} );
-		return await handleBlocksDrop( blocks );
-	}
-
 	const onUpload = ( event ) => {
 		onFilesUpload( event.target.files );
 	};
@@ -385,7 +363,26 @@ export function MediaPlaceholder( {
 			return null;
 		}
 
-		return <DropZone onFilesDrop={ onFilesUpload } onDrop={ onDrop } />;
+		return (
+			<DropZone
+				onFilesDrop={ onFilesUpload }
+				onDrop={ handleBlocksDrop }
+				isEligible={ ( dataTransfer ) => {
+					const prefix = 'wp-block:core/';
+					const types = [];
+					for ( const type of dataTransfer.types ) {
+						if ( type.startsWith( prefix ) ) {
+							types.push( type.slice( prefix.length ) );
+						}
+					}
+					return (
+						types.every( ( type ) =>
+							allowedTypes.includes( type )
+						) && ( multiple ? true : types.length === 1 )
+					);
+				} }
+			/>
+		);
 	};
 
 	const renderCancelLink = () => {

packages/components/CHANGELOG.md

@@ -30,6 +30,7 @@
 -   `ColorPicker`: Update sizes of color format select and copy button ([#67093](https://github.com/WordPress/gutenberg/pull/67093)).
 -   `ComboboxControl`: Update reset button size ([#67215](https://github.com/WordPress/gutenberg/pull/67215)).
 -   `Autocomplete`: Increase option height ([#67214](https://github.com/WordPress/gutenberg/pull/67214)).
+-   `DropZone`: Add `isEligible` prop to allow customizing whether the drop zone should activate ([#67317](https://github.com/WordPress/gutenberg/pull/67317)).
 -   `CircularOptionPicker`: Update `Button` sizes to be ready for 40px default size ([#67285](https://github.com/WordPress/gutenberg/pull/67285)).
 
 ### Experimental

packages/components/src/drop-zone/index.tsx

@@ -15,7 +15,7 @@ import { __experimentalUseDropZone as useDropZone } from '@wordpress/compose';
 /**
  * Internal dependencies
  */
-import type { DropType, DropZoneProps } from './types';
+import type { DropZoneProps } from './types';
 import type { WordPressComponentProps } from '../context';
 
 /**
@@ -47,19 +47,22 @@ export function DropZoneComponent( {
 	onFilesDrop,
 	onHTMLDrop,
 	onDrop,
+	isEligible = () => true,
 	...restProps
 }: WordPressComponentProps< DropZoneProps, 'div', false > ) {
 	const [ isDraggingOverDocument, setIsDraggingOverDocument ] =
 		useState< boolean >();
 	const [ isDraggingOverElement, setIsDraggingOverElement ] =
 		useState< boolean >();
-	const [ type, setType ] = useState< DropType >();
+	const [ isActive, setIsActive ] = useState< boolean >();
 	const ref = useDropZone( {
 		onDrop( event ) {
-			const files = event.dataTransfer
-				? getFilesFromDataTransfer( event.dataTransfer )
-				: [];
-			const html = event.dataTransfer?.getData( 'text/html' );
+			if ( ! event.dataTransfer ) {
+				return;
+			}
+
+			const files = getFilesFromDataTransfer( event.dataTransfer );
+			const html = event.dataTransfer.getData( 'text/html' );
 
 			/**
 			 * From Windows Chrome 96, the `event.dataTransfer` returns both file object and HTML.
@@ -76,32 +79,31 @@ export function DropZoneComponent( {
 		onDragStart( event ) {
 			setIsDraggingOverDocument( true );
 
-			let _type: DropType = 'default';
+			if ( ! event.dataTransfer ) {
+				return;
+			}
 
 			/**
 			 * From Windows Chrome 96, the `event.dataTransfer` returns both file object and HTML.
 			 * The order of the checks is important to recognize the HTML drop.
 			 */
-			if ( event.dataTransfer?.types.includes( 'text/html' ) ) {
-				_type = 'html';
+			if ( event.dataTransfer.types.includes( 'text/html' ) ) {
+				setIsActive( !! onHTMLDrop );
 			} else if (
 				// Check for the types because sometimes the files themselves
 				// are only available on drop.
-				event.dataTransfer?.types.includes( 'Files' ) ||
-				( event.dataTransfer
-					? getFilesFromDataTransfer( event.dataTransfer )
-					: []
-				).length > 0
+				event.dataTransfer.types.includes( 'Files' ) ||
+				getFilesFromDataTransfer( event.dataTransfer ).length > 0
 			) {
-				_type = 'file';
+				setIsActive( !! onFilesDrop );
+			} else {
+				setIsActive( !! onDrop && isEligible( event.dataTransfer ) );
 			}
-
-			setType( _type );
 		},
 		onDragEnd() {
 			setIsDraggingOverElement( false );
 			setIsDraggingOverDocument( false );
-			setType( undefined );
+			setIsActive( undefined );
 		},
 		onDragEnter() {
 			setIsDraggingOverElement( true );
@@ -112,14 +114,9 @@ export function DropZoneComponent( {
 	} );
 
 	const classes = clsx( 'components-drop-zone', className, {
-		'is-active':
-			( isDraggingOverDocument || isDraggingOverElement ) &&
-			( ( type === 'file' && onFilesDrop ) ||
-				( type === 'html' && onHTMLDrop ) ||
-				( type === 'default' && onDrop ) ),
+		'is-active': isActive,
 		'is-dragging-over-document': isDraggingOverDocument,
 		'is-dragging-over-element': isDraggingOverElement,
-		[ `is-dragging-${ type }` ]: !! type,
 	} );
 
 	return (

packages/components/src/drop-zone/types.ts

@@ -26,4 +26,9 @@ export type DropZoneProps = {
 	 * It receives the HTML being dropped as an argument.
 	 */
 	onHTMLDrop?: ( html: string ) => void;
+	/**
+	 * A function to determine if the drop zone is eligible to handle the drop
+	 * data transfer items.
+	 */
+	isEligible?: ( dataTransfer: DataTransfer ) => boolean;
 };

test/e2e/specs/editor/blocks/image.spec.js

@@ -528,14 +528,13 @@ test.describe( 'Image', () => {
 			name: 'Block: Image',
 		} );
 
-		const html = `
-			<figure>
-				<img src="https://live.staticflickr.com/3894/14962688165_04759a8b03_b.jpg" alt="Cat">
-				<figcaption>"Cat" by tomhouslay is licensed under <a href="https://creativecommons.org/licenses/by-nc/2.0/?ref=openverse">CC BY-NC 2.0</a>.</figcaption>
-			</figure>
-		`;
-
-		await page.evaluate( ( _html ) => {
+		await page.evaluate( () => {
+			const { createBlock } = window.wp.blocks;
+			const block = createBlock( 'core/image', {
+				url: 'https://live.staticflickr.com/3894/14962688165_04759a8b03_b.jpg',
+				alt: 'Cat',
+				caption: `"Cat" by tomhouslay is licensed under <a href="https://creativecommons.org/licenses/by-nc/2.0/?ref=openverse">CC BY-NC 2.0</a>.`,
+			} );
 			const dummy = document.createElement( 'div' );
 			dummy.style.width = '10px';
 			dummy.style.height = '10px';
@@ -545,13 +544,17 @@ test.describe( 'Image', () => {
 			dummy.style.left = 0;
 			dummy.draggable = 'true';
 			dummy.addEventListener( 'dragstart', ( event ) => {
-				event.dataTransfer.setData( 'default', _html );
+				event.dataTransfer.setData(
+					'wp-blocks',
+					JSON.stringify( { blocks: [ block ] } )
+				);
+				event.dataTransfer.setData( 'wp-block:core/image', '' );
 				setTimeout( () => {
 					dummy.remove();
 				}, 0 );
 			} );
 			document.body.appendChild( dummy );
-		}, html );
+		} );
 
 		await page.mouse.move( 0, 0 );
 		await page.mouse.down();