/* eslint-disable */
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class XhrLoader {
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constructor(config) {
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if (config && config.xhrSetup) {
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this.xhrSetup = config.xhrSetup;
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}
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}
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destroy() {
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this.abort();
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this.loader = null;
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}
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abort() {
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var loader = this.loader;
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if (loader && loader.readyState !== 4) {
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this.stats.aborted = true;
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loader.abort();
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}
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window.clearTimeout(this.requestTimeout);
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this.requestTimeout = null;
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window.clearTimeout(this.retryTimeout);
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this.retryTimeout = null;
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}
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loadHead(context, config, callbacks) {
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this.context = context;
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this.config = config;
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this.callbacks = callbacks;
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this.stats = {trequest: performance.now(), retry: 0};
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this.retryDelay = config.retryDelay;
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var xhr = new XMLHttpRequest;
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xhr.open('head', context.url);
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xhr.onload = function () {
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callbacks.onSuccess(xhr.getResponseHeader('content-length'));
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};
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xhr.send();
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}
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load(context, config, callbacks) {
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this.context = context;
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this.config = config;
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this.callbacks = callbacks;
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this.stats = {trequest: performance.now(), retry: 0};
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this.retryDelay = config.retryDelay;
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this.loadInternal();
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}
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loadInternal() {
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var xhr, context = this.context;
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if (typeof XDomainRequest !== 'undefined') {
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xhr = this.loader = new XDomainRequest();
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} else {
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xhr = this.loader = new XMLHttpRequest();
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}
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xhr.onloadend = this.loadend.bind(this);
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xhr.onprogress = this.loadprogress.bind(this);
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xhr.open('GET', context.url, true);
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if (context.rangeEnd) {
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xhr.setRequestHeader('Range','bytes=' + context.rangeStart + '-' + (context.rangeEnd-1));
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}
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xhr.responseType = context.responseType;
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let stats = this.stats;
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stats.tfirst = 0;
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stats.loaded = 0;
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if (this.xhrSetup) {
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this.xhrSetup(xhr, context.url);
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}
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// setup timeout before we perform request
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this.requestTimeout = window.setTimeout(this.loadtimeout.bind(this), this.config.timeout);
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xhr.send();
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}
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loadend(event) {
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var xhr = event.currentTarget,
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status = xhr.status,
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stats = this.stats,
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context = this.context,
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config = this.config;
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// don't proceed if xhr has been aborted
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if (stats.aborted) {
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return;
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}
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// in any case clear the current xhrs timeout
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window.clearTimeout(this.requestTimeout);
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// http status between 200 to 299 are all successful
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if (status >= 200 && status < 300) {
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stats.tload = Math.max(stats.tfirst,performance.now());
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let data,len;
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if (context.responseType === 'arraybuffer') {
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data = xhr.response;
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len = data.byteLength;
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} else {
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data = xhr.responseText;
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len = data.length;
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}
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stats.loaded = stats.total = len;
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let response = { url : xhr.responseURL, data : data };
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this.callbacks.onSuccess(response, stats, context);
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} else {
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// if max nb of retries reached or if http status between 400 and 499 (such error cannot be recovered, retrying is useless), return error
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if (stats.retry >= config.maxRetry || (status >= 400 && status < 499)) {
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// logger.error(`${status} while loading ${context.url}` );
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this.callbacks.onError({ code : status, text : xhr.statusText}, context);
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} else {
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// retry
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// logger.warn(`${status} while loading ${context.url}, retrying in ${this.retryDelay}...`);
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// aborts and resets internal state
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this.destroy();
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// schedule retry
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this.retryTimeout = window.setTimeout(this.loadInternal.bind(this), this.retryDelay);
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// set exponential backoff
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this.retryDelay = Math.min(2 * this.retryDelay, config.maxRetryDelay);
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stats.retry++;
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}
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}
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}
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loadtimeout() {
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// logger.warn(`timeout while loading ${this.context.url}` );
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this.callbacks.onTimeout(this.stats, this.context);
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}
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loadprogress(event) {
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var stats = this.stats;
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if (stats.tfirst === 0) {
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stats.tfirst = Math.max(performance.now(), stats.trequest);
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}
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stats.loaded = event.loaded;
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if (event.lengthComputable) {
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stats.total = event.total;
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}
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let onProgress = this.callbacks.onProgress;
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if (onProgress) {
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// last args is to provide on progress data
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onProgress(stats, this.context, null);
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}
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}
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}
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export default XhrLoader;
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