dns-query/lib.browser.js

Node & Browser tested, Non-JSON DNS over HTTPS fetching with minimal dependencies.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.loadJSON = loadJSON;
exports.processResolvers = processResolvers;
exports.queryDns = queryDns;
exports.request = request;

var utf8Codec = _interopRequireWildcard(require("utf8-codec"), true);

var _base64Codec = require("@leichtgewicht/base64-codec");

var _common = require("./common.js");

function _getRequireWildcardCache(nodeInterop) { if (typeof WeakMap !== "function") return null; var cacheBabelInterop = new WeakMap(); var cacheNodeInterop = new WeakMap(); return (_getRequireWildcardCache = function (nodeInterop) { return nodeInterop ? cacheNodeInterop : cacheBabelInterop; })(nodeInterop); }

function _interopRequireWildcard(obj, nodeInterop) { if (!nodeInterop && obj && obj.__esModule) { return obj; } if (obj === null || typeof obj !== "object" && typeof obj !== "function") { return { default: obj }; } var cache = _getRequireWildcardCache(nodeInterop); if (cache && cache.has(obj)) { return cache.get(obj); } var newObj = {}; var hasPropertyDescriptor = Object.defineProperty && Object.getOwnPropertyDescriptor; for (var key in obj) { if (key !== "default" && Object.prototype.hasOwnProperty.call(obj, key)) { var desc = hasPropertyDescriptor ? Object.getOwnPropertyDescriptor(obj, key) : null; if (desc && (desc.get || desc.set)) { Object.defineProperty(newObj, key, desc); } else { newObj[key] = obj[key]; } } } newObj.default = obj; if (cache) { cache.set(obj, newObj); } return newObj; }

/* global XMLHttpRequest, localStorage */
const contentType = 'application/dns-message';

function noop() {}

function queryDns() {
  throw new Error('Only "doh" endpoints are supported in the browser');
}

async function loadJSON(url, cache, timeout, abortSignal) {
  const cacheKey = cache ? cache.localStoragePrefix + cache.name : null;

  if (cacheKey) {
    try {
      const cached = JSON.parse(localStorage.getItem(cacheKey));

      if (cached && cached.time > cache.maxTime) {
        return cached;
      }
    } catch (err) {}
  }

  const {
    data
  } = await requestRaw(url, 'GET', null, timeout, abortSignal);
  const result = {
    time: Date.now(),
    data: JSON.parse(utf8Codec.decode(data))
  };

  if (cacheKey) {
    try {
      localStorage.setItem(cacheKey, JSON.stringify(result));
    } catch (err) {
      result.time = null;
    }
  }

  return result;
}

function requestRaw(url, method, data, timeout, abortSignal) {
  return new Promise((resolve, reject) => {
    const target = new _common.URL(url);

    if (method === 'GET' && data) {
      target.search = '?dns=' + _base64Codec.base64URL.decode(data);
    }

    const uri = target.toString();
    const xhr = new XMLHttpRequest();
    xhr.open(method, uri, true);
    xhr.setRequestHeader('Accept', contentType);

    if (method === 'POST') {
      xhr.setRequestHeader('Content-Type', contentType);
    }

    xhr.responseType = 'arraybuffer';
    xhr.timeout = timeout;
    xhr.ontimeout = ontimeout;
    xhr.onreadystatechange = onreadystatechange;
    xhr.onerror = onerror;
    xhr.onload = onload;

    if (method === 'POST') {
      xhr.send(data);
    } else {
      xhr.send();
    }

    if (abortSignal) {
      abortSignal.addEventListener('abort', onabort);
    }

    function ontimeout() {
      finish(new _common.TimeoutError(timeout));

      try {
        xhr.abort();
      } catch (e) {}
    }

    function onload() {
      if (xhr.status !== 200) {
        finish(new _common.HTTPStatusError(uri, xhr.status, method));
      } else {
        let buf;

        if (typeof xhr.response === 'string') {
          buf = utf8Codec.encode(xhr.response);
        } else if (xhr.response instanceof Uint8Array) {
          buf = xhr.response;
        } else if (Array.isArray(xhr.response) || xhr.response instanceof ArrayBuffer) {
          buf = new Uint8Array(xhr.response);
        } else {
          throw new Error('Unprocessable response ' + xhr.response);
        }

        finish(null, buf);
      }
    }

    function onreadystatechange() {
      if (xhr.readyState > 1 && xhr.status !== 200 && xhr.status !== 0) {
        finish(new _common.HTTPStatusError(uri, xhr.status, method));

        try {
          xhr.abort();
        } catch (e) {}
      }
    }

    let finish = function (error, data) {
      finish = noop;

      if (abortSignal) {
        abortSignal.removeEventListener('abort', onabort);
      }

      if (error) {
        resolve({
          error,
          response: xhr
        });
      } else {
        resolve({
          data,
          response: xhr
        });
      }
    };

    function onerror() {
      finish(xhr.status === 200 ? new Error('Inexplicable XHR Error') : new _common.HTTPStatusError(uri, xhr.status, method));
    }

    function onabort() {
      finish(new _common.AbortError());

      try {
        xhr.abort();
      } catch (e) {}
    }
  });
}

function request(url, method, packet, timeout, abortSignal) {
  return requestRaw(url, method, packet, timeout, abortSignal);
}

function processResolvers(resolvers) {
  return resolvers.filter(resolver => resolver.cors || resolver.endpoint.cors);
}