dns: add promisified dns module

PR-URL: #21264 Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
nodejs · Jun 20, 2018 · aa864ba · aa864ba
1 parent 9cef72d
commit aa864ba
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Showing 16 changed files with 1,551 additions and 406 deletions.
diff --git a/doc/api/dns.md b/doc/api/dns.md
diff --git a/lib/dns.js b/lib/dns.js
@@ -26,10 +26,15 @@ const { isIP, isIPv4, isLegalPort } = require('internal/net');
 const { customPromisifyArgs } = require('internal/util');
 const errors = require('internal/errors');
 const {
-  ERR_DNS_SET_SERVERS_FAILED,
+  bindDefaultResolver,
+  getDefaultResolver,
+  setDefaultResolver,
+  Resolver,
+  validateHints
+} = require('internal/dns/utils');
+const {
   ERR_INVALID_ARG_TYPE,
   ERR_INVALID_CALLBACK,
-  ERR_INVALID_IP_ADDRESS,
   ERR_INVALID_OPT_VALUE,
   ERR_MISSING_ARGS,
   ERR_SOCKET_BAD_PORT
@@ -39,12 +44,13 @@ const {
   GetAddrInfoReqWrap,
   GetNameInfoReqWrap,
   QueryReqWrap,
-  ChannelWrap,
 } = cares;
 
-const IANA_DNS_PORT = 53;
 const dnsException = errors.dnsException;
 
+let promisesWarn = true;
+let promises; // Lazy loaded
+
 function onlookup(err, addresses) {
   if (err) {
     return this.callback(dnsException(err, 'getaddrinfo', this.hostname));
@@ -97,12 +103,7 @@ function lookup(hostname, options, callback) {
     all = options.all === true;
     verbatim = options.verbatim === true;
 
-    if (hints !== 0 &&
-        hints !== cares.AI_ADDRCONFIG &&
-        hints !== cares.AI_V4MAPPED &&
-        hints !== (cares.AI_ADDRCONFIG | cares.AI_V4MAPPED)) {
-      throw new ERR_INVALID_OPT_VALUE('hints', hints);
-    }
+    validateHints(hints);
   } else {
     family = options >>> 0;
   }
@@ -197,17 +198,6 @@ function onresolve(err, result, ttls) {
     this.callback(null, result);
 }
 
-// Resolver instances correspond 1:1 to c-ares channels.
-class Resolver {
-  constructor() {
-    this._handle = new ChannelWrap();
-  }
-
-  cancel() {
-    this._handle.cancel();
-  }
-}
-
 function resolver(bindingName) {
   function query(name, /* options, */ callback) {
     var options;
@@ -270,101 +260,15 @@ function resolve(hostname, rrtype, callback) {
   }
 }
 
-
-Resolver.prototype.getServers = getServers;
-function getServers() {
-  const ret = this._handle.getServers();
-  return ret.map((val) => {
-    if (!val[1] || val[1] === IANA_DNS_PORT) return val[0];
-
-    const host = isIP(val[0]) === 6 ? `[${val[0]}]` : val[0];
-    return `${host}:${val[1]}`;
-  });
-}
-
-
-Resolver.prototype.setServers = setServers;
-function setServers(servers) {
-  // cache the original servers because in the event of an error setting the
-  // servers cares won't have any servers available for resolution
-  const orig = this._handle.getServers();
-  const newSet = [];
-  const IPv6RE = /^\[([^[\]]*)\]/;
-  const addrSplitRE = /(^.+?)(?::(\d+))?$/;
-
-  servers.forEach((serv) => {
-    var ipVersion = isIP(serv);
-    if (ipVersion !== 0)
-      return newSet.push([ipVersion, serv, IANA_DNS_PORT]);
-
-    const match = serv.match(IPv6RE);
-    // we have an IPv6 in brackets
-    if (match) {
-      ipVersion = isIP(match[1]);
-      if (ipVersion !== 0) {
-        const port =
-          parseInt(serv.replace(addrSplitRE, '$2')) ||
-          IANA_DNS_PORT;
-        return newSet.push([ipVersion, match[1], port]);
-      }
-    }
-
-    // addr::port
-    const addrSplitMatch = serv.match(addrSplitRE);
-    if (addrSplitMatch) {
-      const hostIP = addrSplitMatch[1];
-      const port = addrSplitMatch[2] || IANA_DNS_PORT;
-
-      ipVersion = isIP(hostIP);
-      if (ipVersion !== 0) {
-        return newSet.push([ipVersion, hostIP, parseInt(port)]);
-      }
-    }
-
-    throw new ERR_INVALID_IP_ADDRESS(serv);
-  });
-
-  const errorNumber = this._handle.setServers(newSet);
-
-  if (errorNumber !== 0) {
-    // reset the servers to the old servers, because ares probably unset them
-    this._handle.setServers(orig.join(','));
-
-    var err = cares.strerror(errorNumber);
-    throw new ERR_DNS_SET_SERVERS_FAILED(err, servers);
-  }
-}
-
-let defaultResolver = new Resolver();
-
-const resolverKeys = [
-  'getServers',
-  'resolve',
-  'resolveAny',
-  'resolve4',
-  'resolve6',
-  'resolveCname',
-  'resolveMx',
-  'resolveNs',
-  'resolveTxt',
-  'resolveSrv',
-  'resolvePtr',
-  'resolveNaptr',
-  'resolveSoa',
-  'reverse'
-];
-
-function setExportsFunctions() {
-  resolverKeys.forEach((key) => {
-    module.exports[key] = defaultResolver[key].bind(defaultResolver);
-  });
-}
-
 function defaultResolverSetServers(servers) {
   const resolver = new Resolver();
+
   resolver.setServers(servers);
-  defaultResolver = resolver;
-  setExportsFunctions();
+  setDefaultResolver(resolver);
+  bindDefaultResolver(module.exports, Resolver.prototype);
+
+  if (promises !== undefined)
+    bindDefaultResolver(promises, promises.Resolver.prototype);
 }
 
 module.exports = {
@@ -405,4 +309,21 @@ module.exports = {
   CANCELLED: 'ECANCELLED'
 };
 
-setExportsFunctions();
+bindDefaultResolver(module.exports, getDefaultResolver());
+
+Object.defineProperties(module.exports, {
+  promises: {
+    configurable: true,
+    enumerable: false,
+    get() {
+      if (promisesWarn) {
+        promises = require('internal/dns/promises');
+        promises.setServers = defaultResolverSetServers;
+        promisesWarn = false;
+        process.emitWarning('The dns.promises API is experimental',
+                            'ExperimentalWarning');
+      }
+      return promises;
+    }
+  }
+});