/**
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* 文件转换
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* @author Tevin
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*/
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import moment from 'moment';
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export class FileTransform {
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constructor() {
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this._data = {
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chunkSize: 20 * 1024,
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};
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}
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getChunkSize() {
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return this._data.chunkSize;
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}
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setChunkSize() {
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return this._data.chunkSize;
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}
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/**
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* 转换 ObjectURL 为 base64 数据体（用于java通讯）
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* @param objUrl
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* @param callback
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*/
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transObjUrlToBaseData(objUrl, callback) {
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this.convertObjectUrlToBlob(objUrl, blob => {
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this.convertBlobToBase64(blob, base64 => {
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const mime = base64.split(',')[0].match(/:(.*?);/)[1];
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const fileName = this._makeFileName(mime);
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const baseArr = this.splitBase64ToArray(base64);
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callback && callback({
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fileName,
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baseArr,
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total: baseArr.length,
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});
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});
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});
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}
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/**
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* 转换 base64 数据体为 ObjectURL（用于java通讯）
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* @param baseData
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* @param callback
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*/
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transBaseDataToObjUrl(baseData, callback) {
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const base64 = baseData.baseArr.join('');
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this.convertBase64ToFile(base64, baseData.fileName, file => {
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this.convertFileToObjectUrl(file, objUrl => {
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callback && callback(objUrl);
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});
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});
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}
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convertBlobToBase64(blob, callback) {
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const reader = new FileReader();
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reader.onload = evt => {
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callback && callback(evt.target.result);
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};
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reader.readAsDataURL(blob);
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}
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convertObjectUrlToBlob(objUrl, callback) {
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const xhr = new XMLHttpRequest();
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xhr.open('GET', objUrl, true);
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xhr.responseType = 'blob';
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xhr.onload = function () {
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if (this.status === 200) {
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callback && callback(this.response);
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} else {
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/* eslint-disable prefer-promise-reject-errors */
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callback && callback(null, { status: this.status });
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}
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};
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xhr.send();
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}
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convertBase64ToFile(base64, fileName, callback) {
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const arr = base64.split(',');
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const mime = arr[0].match(/:(.*?);/)[1];
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const bstr = atob(arr[1]);
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let n = bstr.length;
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const u8arr = new Uint8Array(n);
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while (n--) {
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u8arr[n] = bstr.charCodeAt(n);
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}
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fileName = fileName || this._makeFileName(mime);
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const file = new File([u8arr], fileName, { type: mime });
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callback && callback(file);
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}
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convertFileToObjectUrl(file, callback) {
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let URLMaker = URL;
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if (window) {
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URLMaker = window.URL || window.webkitURL;
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}
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const url = URLMaker.createObjectURL(file);
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callback && callback(url);
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}
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// 生成文件名
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_makeFileName(mime) {
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const curMoment = moment();
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const name = 'IMG' + curMoment.format('-YYYYMMDD-HHmmss-') +
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curMoment.format('x').substr(-3) + '-' + parseInt(Math.random() * 10000);
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const mimeTypes = {
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'image/jpeg': 'jpg',
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'image/gif': 'gif',
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'image/png': 'png',
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'image/svg+xml': 'svg',
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'image/webp': 'webp',
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'image/tiff': 'tif',
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'text/plain': 'txt',
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'text/css': 'css',
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'text/html': 'html',
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'text/xml': 'xml',
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'text/javascript': 'js',
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'application/x-javascript': 'js',
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'audio/mpeg': 'mp3',
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'video/mp4': 'mp4',
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'video/webm': 'webm',
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'application/zip': 'zip',
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'application/rar': 'rar',
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'application/pdf': 'pdf',
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'application/rtf': 'rtf',
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};
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return name + '.' + mimeTypes[mime];
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}
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splitBase64ToArray(base64) {
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const count = Math.ceil(base64.length / this._data.chunkSize);
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if (count === 1) {
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return [base64];
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}
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const array = [];
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for (let i = 0; i < count; i++) {
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const chunk = base64.substr(this._data.chunkSize * i, this._data.chunkSize);
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array.push(chunk);
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}
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return array;
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}
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/**
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* 读取文件 base64
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* @param {File} file
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* @param {Function} callback
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*/
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getFileBase64(file, callback) {
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const reader = new FileReader();
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reader.onload = () => callback(reader.result);
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reader.onerror = error => callback(null, error);
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reader.readAsDataURL(file);
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}
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}
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export const $fileTrans = new FileTransform();
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