50 lines
1.6 KiB
JavaScript
50 lines
1.6 KiB
JavaScript
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import {query} from 'dns-query';
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function get_prefered_server() {
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try {
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const servers = JSON.parse(localStorage.getItem('dns-servers'));
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if (servers && servers.length > 0) {
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return servers;
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}
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} catch (e) {
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console.error(e);
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}
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const request = new XMLHttpRequest();
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request.open('GET', '/local/dns', false);
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request.send(null);
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if (request.status === 200) {
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const servers = JSON.parse(request.responseText);
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if (servers && servers.length > 0) {
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return servers;
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}
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}
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return ['1.1.1.1', '8.8.8.8'];
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}
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class FallBackResolver {
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constructor() {
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this._servers = get_prefered_server();
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this._cache = JSON.parse(localStorage.getItem('dns-cache')) || {};
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}
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async query(domain, type) {
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const key = domain + ':' + type;
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if (key in this._cache && this._cache[key].time > Date.now() - 1000 * 60 * 60) {
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const age_seconds = Math.ceil(Date.now() / 1000 - this._cache[key].time / 1000);
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return [this._cache[key].data];
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}
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const result = await query(
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{question: {type: type, name: domain}},
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{
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endpoints: this._servers,
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}
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)
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if (result.answers.length === 0) throw new Error('No answer');
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const first = result.answers[0];
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this._cache[key] = {time: Date.now(), ...first}; // TODO hadle multiple answers
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localStorage.setItem('dns-cache', JSON.stringify(this._cache));
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return [first.data];
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}
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}
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export default FallBackResolver;
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