Merge pull request #248 from ckeditor/t/246

Feature: Support for uploading images with base64 source. Closes #246. Closes ckeditor/ckeditor5-paste-from-office#24.

Author: Reinmar

src/imageupload/imageuploadediting.js

@@ -10,9 +10,11 @@
 import Plugin from '@ckeditor/ckeditor5-core/src/plugin';
 import FileRepository from '@ckeditor/ckeditor5-upload/src/filerepository';
 import Notification from '@ckeditor/ckeditor5-ui/src/notification/notification';
+import UpcastWriter from '@ckeditor/ckeditor5-engine/src/view/upcastwriter';
+import { upcastAttributeToAttribute } from '@ckeditor/ckeditor5-engine/src/conversion/upcast-converters';
 
 import ImageUploadCommand from '../../src/imageupload/imageuploadcommand';
-import { isImageType } from '../../src/imageupload/utils';
+import { isImageType, isLocalImage, fetchLocalImage } from '../../src/imageupload/utils';
 
 /**
  * The editing part of the image upload feature. It registers the `'imageUpload'` command.
@@ -34,6 +36,7 @@ export default class ImageUploadEditing extends Plugin {
 		const editor = this.editor;
 		const doc = editor.model.document;
 		const schema = editor.model.schema;
+		const conversion = editor.conversion;
 		const fileRepository = editor.plugins.get( FileRepository );
 
 		// Setup schema to allow uploadId and uploadStatus for images.
@@ -44,6 +47,16 @@ export default class ImageUploadEditing extends Plugin {
 		// Register imageUpload command.
 		editor.commands.add( 'imageUpload', new ImageUploadCommand( editor ) );
 
+		// Register upcast converter for uploadId.
+		conversion.for( 'upcast' )
+			.add( upcastAttributeToAttribute( {
+				view: {
+					name: 'img',
+					key: 'uploadId'
+				},
+				model: 'uploadId'
+			} ) );
+
 		// Handle pasted images.
 		// For every image file, a new file loader is created and a placeholder image is
 		// inserted into the content. Then, those images are uploaded once they appear in the model
@@ -81,6 +94,48 @@ export default class ImageUploadEditing extends Plugin {
 			} );
 		} );
 
+		// Handle HTML pasted with images with base64 or blob sources.
+		// For every image file, a new file loader is created and a placeholder image is
+		// inserted into the content. Then, those images are uploaded once they appear in the model
+		// (see Document#change listener below).
+		this.listenTo( editor.plugins.get( 'Clipboard' ), 'inputTransformation', ( evt, data ) => {
+			const fetchableImages = Array.from( editor.editing.view.createRangeIn( data.content ) )
+				.filter( value => isLocalImage( value.item ) && !value.item.getAttribute( 'uploadProcessed' ) )
+				.map( value => fetchLocalImage( value.item ) );
+
+			if ( !fetchableImages.length ) {
+				return;
+			}
+
+			evt.stop();
+
+			Promise.all( fetchableImages ).then( items => {
+				const writer = new UpcastWriter();
+
+				for ( const item of items ) {
+					if ( !item.file ) {
+						// Failed to fetch image or create a file instance, remove image element.
+						writer.remove( item.image );
+					} else {
+						// Set attribute marking the image as processed.
+						writer.setAttribute( 'uploadProcessed', true, item.image );
+
+						const loader = fileRepository.createLoader( item.file );
+
+						if ( loader ) {
+							writer.setAttribute( 'src', '', item.image );
+							writer.setAttribute( 'uploadId', loader.id, item.image );
+						}
+					}
+				}
+
+				editor.plugins.get( 'Clipboard' ).fire( 'inputTransformation', {
+					content: data.content,
+					dataTransfer: data.dataTransfer
+				} );
+			} );
+		} );
+
 		// Prevents from the browser redirecting to the dropped image.
 		editor.editing.view.document.on( 'dragover', ( evt, data ) => {
 			data.preventDefault();
@@ -163,33 +218,7 @@ export default class ImageUploadEditing extends Plugin {
 			.then( data => {
 				model.enqueueChange( 'transparent', writer => {
 					writer.setAttributes( { uploadStatus: 'complete', src: data.default }, imageElement );
-
-					// Srcset attribute for responsive images support.
-					let maxWidth = 0;
-					const srcsetAttribute = Object.keys( data )
-						// Filter out keys that are not integers.
-						.filter( key => {
-							const width = parseInt( key, 10 );
-
-							if ( !isNaN( width ) ) {
-								maxWidth = Math.max( maxWidth, width );
-
-								return true;
-							}
-						} )
-
-						// Convert each key to srcset entry.
-						.map( key => `${ data[ key ] } ${ key }w` )
-
-						// Join all entries.
-						.join( ', ' );
-
-					if ( srcsetAttribute != '' ) {
-						writer.setAttribute( 'srcset', {
-							data: srcsetAttribute,
-							width: maxWidth
-						}, imageElement );
-					}
+					this._parseAndSetSrcsetAttributeOnImage( data, imageElement, writer );
 				} );
 
 				clean();
@@ -226,6 +255,44 @@ export default class ImageUploadEditing extends Plugin {
 			fileRepository.destroyLoader( loader );
 		}
 	}
+
+	/**
+	 * Creates `srcset` attribute based on a given file upload response and sets it as an attribute to a specific image element.
+	 *
+	 * @protected
+	 * @param {Object} data Data object from which `srcset` will be created.
+	 * @param {module:engine/model/element~Element} image The image element on which `srcset` attribute will be set.
+	 * @param {module:engine/model/writer~Writer} writer
+	 */
+	_parseAndSetSrcsetAttributeOnImage( data, image, writer ) {
+		// Srcset attribute for responsive images support.
+		let maxWidth = 0;
+
+		const srcsetAttribute = Object.keys( data )
+			// Filter out keys that are not integers.
+			.filter( key => {
+				const width = parseInt( key, 10 );
+
+				if ( !isNaN( width ) ) {
+					maxWidth = Math.max( maxWidth, width );
+
+					return true;
+				}
+			} )
+
+			// Convert each key to srcset entry.
+			.map( key => `${ data[ key ] } ${ key }w` )
+
+			// Join all entries.
+			.join( ', ' );
+
+		if ( srcsetAttribute != '' ) {
+			writer.setAttribute( 'srcset', {
+				data: srcsetAttribute,
+				width: maxWidth
+			}, image );
+		}
+	}
 }
 
 // Returns `true` if non-empty `text/html` is included in the data transfer.

src/imageupload/utils.js

@@ -7,6 +7,8 @@
  * @module image/imageupload/utils
  */
 
+/* global fetch, File */
+
 /**
  * Checks if a given file is an image.
  *
@@ -18,3 +20,80 @@ export function isImageType( file ) {
 
 	return types.test( file.type );
 }
+
+/**
+ * Creates a promise which fetches the image local source (base64 or blob) and returns as a `File` object.
+ *
+ * @param {module:engine/view/element~Element} image Image which source to fetch.
+ * @returns {Promise} A promise which resolves when image source is fetched and converted to `File` instance.
+ * It resolves with object holding initial image element (as `image`) and its file source (as `file`). If
+ * the `file` attribute is null, it means fetching failed.
+ */
+export function fetchLocalImage( image ) {
+	return new Promise( resolve => {
+		// Fetch works asynchronously and so does not block browser UI when processing data.
+		fetch( image.getAttribute( 'src' ) )
+			.then( resource => resource.blob() )
+			.then( blob => {
+				const mimeType = getImageMimeType( blob, image.getAttribute( 'src' ) );
+				const ext = mimeType.replace( 'image/', '' );
+				const filename = `image.${ ext }`;
+				const file = createFileFromBlob( blob, filename, mimeType );
+
+				resolve( { image, file } );
+			} )
+			.catch( () => {
+				// We always resolve a promise so `Promise.all` will not reject if one of many fetch fails.
+				resolve( { image, file: null } );
+			} );
+	} );
+}
+
+/**
+ * Checks whether given node is an image element with local source (base64 or blob).
+ *
+ * @param {module:engine/view/node~Node} node Node to check.
+ * @returns {Boolean}
+ */
+export function isLocalImage( node ) {
+	if ( !node.is( 'element', 'img' ) || !node.getAttribute( 'src' ) ) {
+		return false;
+	}
+
+	return node.getAttribute( 'src' ).match( /^data:image\/\w+;base64,/g ) ||
+		node.getAttribute( 'src' ).match( /^blob:/g );
+}
+
+// Extracts image type based on its blob representation or its source.
+//
+// @param {String} src Image src attribute value.
+// @param {Blob} blob Image blob representation.
+// @returns {String}
+function getImageMimeType( blob, src ) {
+	if ( blob.type ) {
+		return blob.type;
+	} else if ( src.match( /data:(image\/\w+);base64/ ) ) {
+		return src.match( /data:(image\/\w+);base64/ )[ 1 ].toLowerCase();
+	} else {
+		// Fallback to 'jpeg' as common extension.
+		return 'image/jpeg';
+	}
+}
+
+// Creates `File` instance from the given `Blob` instance using specified filename.
+//
+// @param {Blob} blob The `Blob` instance from which file will be created.
+// @param {String} filename Filename used during file creation.
+// @param {String} mimeType File mime type.
+// @returns {File|null} The `File` instance created from the given blob or `null` if `File API` is not available.
+function createFileFromBlob( blob, filename, mimeType ) {
+	try {
+		return new File( [ blob ], filename, { type: mimeType } );
+	} catch ( err ) {
+		// Edge does not support `File` constructor ATM, see https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/9551546/.
+		// However, the `File` function is present (so cannot be checked with `!window.File` or `typeof File === 'function'`), but
+		// calling it with `new File( ... )` throws an error. This try-catch prevents that. Also when the function will
+		// be implemented correctly in Edge the code will start working without any changes (see #247).
+		return null;
+	}
+}

tests/imageupload.js

@@ -6,6 +6,7 @@
 /* globals document */
 
 import ClassicEditor from '@ckeditor/ckeditor5-editor-classic/src/classiceditor';
+import Clipboard from '@ckeditor/ckeditor5-clipboard/src/clipboard';
 import Image from '../src/image';
 import ImageUpload from '../src/imageupload';
 import ImageUploadEditing from '../src/imageupload/imageuploadediting';
@@ -23,7 +24,7 @@ describe( 'ImageUpload', () => {
 
 		return ClassicEditor
 			.create( editorElement, {
-				plugins: [ Image, ImageUpload, UploadAdapterPluginMock ]
+				plugins: [ Image, ImageUpload, UploadAdapterPluginMock, Clipboard ]
 			} )
 			.then( newEditor => {
 				editor = newEditor;