/* * Copyright (C) 2020-2021 Yomichan Authors * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <https://www.gnu.org/licenses/>. */ /* global * MediaUtil */ /** * Class which can read text and images from the clipboard. */ class ClipboardReader { /** * Creates a new instances of a clipboard reader. * @param document The Document object to be used, or null for no support. * @param pasteTargetSelector The selector for the paste target element. * @param imagePasteTargetSelector The selector for the image paste target element. */ constructor({document=null, pasteTargetSelector=null, imagePasteTargetSelector=null}) { this._document = document; this._browser = null; this._pasteTarget = null; this._pasteTargetSelector = pasteTargetSelector; this._imagePasteTarget = null; this._imagePasteTargetSelector = imagePasteTargetSelector; } /** * Gets the browser being used. */ get browser() { return this._browser; } /** * Assigns the browser being used. */ set browser(value) { this._browser = value; } /** * Gets the text in the clipboard. * @returns A string containing the clipboard text. * @throws Error if not supported. */ async getText() { /* Notes: document.execCommand('paste') doesn't work on Firefox. See: https://bugzilla.mozilla.org/show_bug.cgi?id=1603985 Therefore, navigator.clipboard.readText() is used on Firefox. navigator.clipboard.readText() can't be used in Chrome for two reasons: * Requires page to be focused, else it rejects with an exception. * When the page is focused, Chrome will request clipboard permission, despite already being an extension with clipboard permissions. It effectively asks for the non-extension permission for clipboard access. */ if (this._isFirefox()) { try { return await navigator.clipboard.readText(); } catch (e) { // Error is undefined, due to permissions throw new Error('Cannot read clipboard text; check extension permissions'); } } const document = this._document; if (document === null) { throw new Error('Clipboard reading not supported in this context'); } let target = this._pasteTarget; if (target === null) { target = document.querySelector(this._pasteTargetSelector); if (target === null) { throw new Error('Clipboard paste target does not exist'); } this._pasteTarget = target; } target.value = ''; target.focus(); document.execCommand('paste'); const result = target.value; target.value = ''; return (typeof result === 'string' ? result : ''); } /** * Gets the first image in the clipboard. * @returns A string containing a data URL of the image file, or null if no image was found. * @throws Error if not supported. */ async getImage() { // See browser-specific notes in getText if ( this._isFirefox() && typeof navigator.clipboard !== 'undefined' && typeof navigator.clipboard.read === 'function' ) { // This function is behind the Firefox flag: dom.events.asyncClipboard.dataTransfer let files; try { ({files} = await navigator.clipboard.read()); } catch (e) { return null; } for (const file of files) { if (MediaUtil.getFileExtensionFromImageMediaType(file.type) !== null) { return await this._readFileAsDataURL(file); } } return null; } const document = this._document; if (document === null) { throw new Error('Clipboard reading not supported in this context'); } let target = this._imagePasteTarget; if (target === null) { target = document.querySelector(this._imagePasteTargetSelector); if (target === null) { throw new Error('Clipboard paste target does not exist'); } this._imagePasteTarget = target; } target.focus(); document.execCommand('paste'); const image = target.querySelector('img[src^="data:"]'); const result = (image !== null ? image.getAttribute('src') : null); for (const image2 of target.querySelectorAll('img')) { image2.removeAttribute('src'); } target.textContent = ''; return result; } // Private _isFirefox() { return (this._browser === 'firefox' || this._browser === 'firefox-mobile'); } _readFileAsDataURL(file) { return new Promise((resolve, reject) => { const reader = new FileReader(); reader.onload = () => resolve(reader.result); reader.onerror = () => reject(reader.error); reader.readAsDataURL(file); }); } }