feat(dns): added support for a custom lookup function; (#5339)

lib/adapters/http.js

@@ -23,6 +23,7 @@ import EventEmitter from 'events';
 import formDataToStream from "../helpers/formDataToStream.js";
 import readBlob from "../helpers/readBlob.js";
 import ZlibHeaderTransformStream from '../helpers/ZlibHeaderTransformStream.js';
+import callbackify from "../helpers/callbackify.js";
 
 const zlibOptions = {
   flush: zlib.constants.Z_SYNC_FLUSH,
@@ -146,13 +147,24 @@ const wrapAsync = (asyncExecutor) => {
 /*eslint consistent-return:0*/
 export default isHttpAdapterSupported && function httpAdapter(config) {
   return wrapAsync(async function dispatchHttpRequest(resolve, reject, onDone) {
-    let {data} = config;
+    let {data, lookup, family} = config;
     const {responseType, responseEncoding} = config;
     const method = config.method.toUpperCase();
     let isDone;
     let rejected = false;
     let req;
 
+    if (lookup && utils.isAsyncFn(lookup)) {
+      lookup = callbackify(lookup, (entry) => {
+        if(utils.isString(entry)) {
+          entry = [entry, entry.indexOf('.') < 0 ? 6 : 4]
+        } else if (!utils.isArray(entry)) {
+          throw new TypeError('lookup async function must return an array [ip: string, family: number]]')
+        }
+        return entry;
+      })
+    }
+
     // temporary internal emitter until the AxiosRequest class will be implemented
     const emitter = new EventEmitter();
 
@@ -378,6 +390,8 @@ export default isHttpAdapterSupported && function httpAdapter(config) {
       agents: { http: config.httpAgent, https: config.httpsAgent },
       auth,
       protocol,
+      family,
+      lookup,
       beforeRedirect: dispatchBeforeRedirect,
       beforeRedirects: {}
     };