feat: add isUrlResolvable validator and tests This commit adds a new…

README.md

@@ -168,6 +168,7 @@ Validator                               | Description
 **isTime(str [, options])**             | check if the string is a valid time e.g. [`23:01:59`, new Date().toLocaleTimeString()].<br/><br/> `options` is an object which can contain the keys `hourFormat` or `mode`.<br/><br/>`hourFormat` is a key and defaults to `'hour24'`.<br/><br/>`mode` is a key and defaults to `'default'`. <br/><br/>`hourFomat` can contain the values `'hour12'` or `'hour24'`, `'hour24'` will validate hours in 24 format and `'hour12'` will validate hours in 12 format. <br/><br/>`mode` can contain the values `'default'` or `'withSeconds'`, `'default'` will validate `HH:MM` format, `'withSeconds'` will validate the `HH:MM:SS` format.
 **isTaxID(str, locale)**                | check if the string is a valid Tax Identification Number. Default locale is `en-US`.<br/><br/>More info about exact TIN support can be found in `src/lib/isTaxID.js`.<br/><br/>Supported locales: `[ 'bg-BG', 'cs-CZ', 'de-AT', 'de-DE', 'dk-DK', 'el-CY', 'el-GR', 'en-CA', 'en-GB', 'en-IE', 'en-US', 'es-ES', 'et-EE', 'fi-FI', 'fr-BE', 'fr-CA', 'fr-FR', 'fr-LU', 'hr-HR', 'hu-HU', 'it-IT', 'lb-LU', 'lt-LT', 'lv-LV', 'mt-MT', 'nl-BE', 'nl-NL', 'pl-PL', 'pt-BR', 'pt-PT', 'ro-RO', 'sk-SK', 'sl-SI', 'sv-SE' ]`.
 **isURL(str [, options])**              | check if the string is a URL.<br/><br/>`options` is an object which defaults to `{ protocols: ['http','https','ftp'], require_tld: true, require_protocol: false, require_host: true, require_port: false, require_valid_protocol: true, allow_underscores: false, host_whitelist: false, host_blacklist: false, allow_trailing_dot: false, allow_protocol_relative_urls: false, allow_fragments: true, allow_query_components: true, disallow_auth: false, validate_length: true }`.<br/><br/>`require_protocol` - if set to true isURL will return false if protocol is not present in the URL.<br/>`require_valid_protocol` - isURL will check if the URL's protocol is present in the protocols option.<br/>`protocols` - valid protocols can be modified with this option.<br/>`require_host` - if set to false isURL will not check if host is present in the URL.<br/>`require_port` - if set to true isURL will check if port is present in the URL.<br/>`allow_protocol_relative_urls` - if set to true protocol relative URLs will be allowed.<br/>`allow_fragments` - if set to false isURL will return false if fragments are present.<br/>`allow_query_components` - if set to false isURL will return false if query components are present.<br/>`validate_length` - if set to false isURL will skip string length validation (2083 characters is IE max URL length).
+**isUrlResolvable(str)**                | check if a giving url is resolvable via DNS. <br/><br/>API <br/><br/> isUrlResolvable(url:string):boolean. <br/><br/> Returns `true` if the given URL is resolvable via DNS. `false` otherwise. <br/> <br/> `url` - The URL to be check is its resolvable. <br/><br/> Usage <br/><br/>const { isUrlResolvable } = require('validator'); <br/><br/>const url = 'https://www.google.com';<br/><br/>if (isUrlResolvable(url)) {<br/><br/> console.log(`${url} is resolvable`);<br/><br/>} <br/><br/>else { <br/><br/> console.log(`${url} is not resolvable`); <br/><br/>}
 **isUUID(str [, version])**             | check if the string is a UUID (version 1, 2, 3, 4 or 5).
 **isVariableWidth(str)**                | check if the string contains a mixture of full and half-width chars.
 **isVAT(str, countryCode)**             | check if the string is a [valid VAT number][VAT Number] if validation is available for the given country code matching [ISO 3166-1 alpha-2][ISO 3166-1 alpha-2]. <br/><br/>`countryCode` is one of `['AL', 'AR', 'AT', 'AU', 'BE', 'BG', 'BO', 'BR', 'BY', 'CA', 'CH', 'CL', 'CO', 'CR', 'CY', 'CZ', 'DE', 'DK', 'DO', 'EC', 'EE', 'EL', 'ES', 'FI', 'FR', 'GB', 'GT', 'HN', 'HR', 'HU', 'ID', 'IE', 'IL', 'IN', 'IS', 'IT', 'KZ', 'LT', 'LU', 'LV', 'MK', 'MT', 'MX', 'NG', 'NI', 'NL', 'NO', 'NZ', 'PA', 'PE', 'PH', 'PL', 'PT', 'PY', 'RO', 'RS', 'RU', 'SA', 'SE', 'SI', 'SK', 'SM', 'SV', 'TR', 'UA', 'UY', 'UZ', 'VE']`.

src/lib/isUrlResolvable.js

@@ -0,0 +1,35 @@
+/**
+ * isUrlResolvable Function
+ * This function takes a URL string as input and checks if the URL is resolvable by performing a DNS lookup on the hostname.
+ * @param {string} passed_url - The URL string to be checked
+ * @return {boolean} - Returns true if the URL is resolvable, false otherwise
+ */
+const isUrlResolvable = function (passed_url) {
+
+    // Check if passed url has a protocol
+    // If not, add 'http://' by default
+    const urlWithProtocol = passed_url.startsWith('http://') || passed_url.startsWith('https://') ? passed_url : `http://${passed_url}`;
+
+    // Parse the URL to extract the hostname
+    const parsedUrl = new URL(urlWithProtocol);
+
+    // Check that the hostname is valid
+    const hostname = parsedUrl.hostname;
+    if (!hostname) {
+      return false;
+    }
+
+    // Attempt to resolve the hostname using DNS lookup
+    return new Promise((resolve) => {
+      dns.resolve(hostname, (err, records) => {
+        if (err) {
+          resolve(false);
+        } else {
+          resolve(true);
+        }
+      });
+    });
+  };
+
+  module.exports = isUrlResolvable;
+

test/validators/isUrlResolvable.test.js

@@ -0,0 +1,60 @@
+import test from '../testFunctions';
+
+describe('isUrlResolvable', () => {
+  it('should validate resolvable URLs', () => {
+    test({
+      validator: 'isUrlResolvable',
+      valid: [
+        'https://www.google.com/',
+        'https://www.facebook.com/',
+        'https://www.youtube.com/',
+        'https://www.reddit.com/',
+        'https://www.instagram.com/',
+        'https://www.wikipedia.org/',
+        'https://www.linkedin.com/',
+      ],
+      invalid: [
+        'http://localhost/test.html',
+        'example.com',
+        'http://localhost',
+        'ftp://localhost/test.html',
+        'https://madeupdomain3456.com',
+        'https://foo.bar.baz',
+        'https://..com/',
+      ],
+    });
+  });
+
+  it('should let users specify whether URLs require a protocol', () => {
+    test({
+      validator: 'isUrlResolvable',
+      args: [{
+        require_protocol: true,
+      }],
+      valid: [
+        'http://www.example.com/',
+        'https://www.example.com/',
+      ],
+      invalid: [
+        'www.example.com',
+        'example.com',
+      ],
+    });
+  });
+
+  it('should let users specify whether subdomains are allowed', () => {
+    test({
+      validator: 'isUrlResolvable',
+      args: [{
+        allow_subdomains: true,
+      }],
+      valid: [
+        'http://www.example.com/',
+        'http://subdomain.example.com/',
+      ],
+      invalid: [
+        'http://example.com/',
+      ],
+    });
+  });
+});