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- /**
- * @license Copyright (c) 2003-2018, CKSource - Frederico Knabben. All rights reserved.
- * For licensing, see LICENSE.md.
- */
- /**
- * @module image/imageupload/utils
- */
- /* global fetch, File */
- /**
- * Checks if a given file is an image.
- *
- * @param {File} file
- * @returns {Boolean}
- */
- export function isImageType( file ) {
- const types = /^image\/(jpeg|png|gif|bmp)$/;
- return types.test( file.type );
- }
- /**
- * Creates a promise which fetches the image local source (base64 or blob) and resolves with a `File` object.
- *
- * @param {module:engine/view/element~Element} image Image which source to fetch.
- * @returns {Promise.<File>} A promise which resolves when image source is fetched and converted to `File` instance.
- * It resolves with a `File` object. If there were any errors during file processing the promise will be rejected.
- */
- export function fetchLocalImage( image ) {
- return new Promise( ( resolve, reject ) => {
- const imageSrc = image.getAttribute( 'src' );
- // Fetch works asynchronously and so does not block browser UI when processing data.
- fetch( imageSrc )
- .then( resource => resource.blob() )
- .then( blob => {
- const mimeType = getImageMimeType( blob, imageSrc );
- const ext = mimeType.replace( 'image/', '' );
- const filename = `image.${ ext }`;
- const file = createFileFromBlob( blob, filename, mimeType );
- file ? resolve( file ) : reject();
- } )
- .catch( reject );
- } );
- }
- /**
- * 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;
- }
- }
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