02_advanced/uebungen/u13_dns-lookup/index.js

@@ -0,0 +1,54 @@
+// const dns = require('node:dns'); // commonjs
+import dns from 'node:dns'; // esm module
+import util from 'node:util';
+import color from 'chalk';
+
+const IP_V = 4; // we use IP protocol version 4
+const URL = 'google.de';
+
+const getIpBy = (url, ipVersion = 4) => {
+  return new Promise((resolve, reject) => {
+    // async process
+    dns.lookup(url, ipVersion, (error, address) => {
+      if (error) {
+        reject(error);
+      } else {
+        resolve({ address: address, family: ipVersion });
+      }
+    });
+  });
+};
+
+// Promises Unterobjekt von Node
+const getPromisesIpBy = (url, ipVersion = 4) => {
+  // async process
+  return dns.promises.lookup(url, ipVersion);
+};
+
+// Promisify Helferfunktion
+const getPromisifyIpBy = util.promisify(dns.lookup);
+
+// Test Cases:
+getIpBy(URL, IP_V)
+  .then((data) => {
+    console.log(data);
+  })
+  .catch((err) => {
+    console.log(color.red(err));
+  });
+
+getPromisesIpBy(URL)
+  .then((data) => {
+    console.log(data);
+  })
+  .catch((err) => {
+    console.log(color.red(err));
+  });
+
+getPromisifyIpBy(URL, IP_V)
+  .then((data) => {
+    console.log(data);
+  })
+  .catch((err) => {
+    console.log(color.red(err));
+  });

02_advanced/uebungen/u13_dns-lookup/package-lock.json

@@ -0,0 +1,28 @@
+{
+  "name": "u13_dns-lookup",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "u13_dns-lookup",
+      "version": "1.0.0",
+      "license": "ISC",
+      "dependencies": {
+        "chalk": "^5.6.2"
+      }
+    },
+    "node_modules/chalk": {
+      "version": "5.6.2",
+      "resolved": "https://registry.npmjs.org/chalk/-/chalk-5.6.2.tgz",
+      "integrity": "sha512-7NzBL0rN6fMUW+f7A6Io4h40qQlG+xGmtMxfbnH/K7TAtt8JQWVQK+6g0UXKMeVJoyV5EkkNsErQ8pVD3bLHbA==",
+      "license": "MIT",
+      "engines": {
+        "node": "^12.17.0 || ^14.13 || >=16.0.0"
+      },
+      "funding": {
+        "url": "https://github.com/chalk/chalk?sponsor=1"
+      }
+    }
+  }
+}

02_advanced/uebungen/u13_dns-lookup/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "u13_dns-lookup",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "type": "module",
+  "dependencies": {
+    "chalk": "^5.6.2"
+  }
+}