Use node 7+ WHATWG parser for hostname, fixes #1002

lib/request.js

@@ -5,6 +5,7 @@
  * Module dependencies.
  */
 
+const URL = require('url').URL;
 const net = require('net');
 const contentType = require('content-type');
 const stringify = require('url').format;
@@ -244,9 +245,28 @@ module.exports = {
   get hostname() {
     const host = this.host;
     if (!host) return '';
+    if ('[' == host[0]) return this.URL.hostname; // IPv6
     return host.split(':')[0];
   },
 
+  /**
+   * Get WHATWG parsed URL.
+   * Lazily memoized.
+   *
+   * @return {URL}
+   * @api public
+   */
+
+  get URL() {
+    if (!this.memoizedURL) {
+      const protocol = this.protocol;
+      const host = this.host;
+      const originalUrl = this.originalUrl || ''; // avoid undefined in template string
+      this.memoizedURL = new URL(`${protocol}://${host}${originalUrl}`);
+    }
+    return this.memoizedURL;
+  },
+
   /**
    * Check if the request is fresh, aka
    * Last-Modified and/or the ETag

test/request/hostname.js

@@ -18,6 +18,32 @@ describe('req.hostname', () => {
     });
   });
 
+  describe('with IPv6 in host', () => {
+    it('should parse localhost void of port', () => {
+      const req = request();
+      req.header.host = '[::1]';
+      assert.equal(req.hostname, '[::1]');
+    });
+
+    it('should parse localhost with port 80', () => {
+      const req = request();
+      req.header.host = '[::1]:80';
+      assert.equal(req.hostname, '[::1]');
+    });
+
+    it('should parse localhost with non special schema port', () => {
+      const req = request();
+      req.header.host = '[::1]:1337';
+      assert.equal(req.hostname, '[::1]');
+    });
+
+    it('should reduce IPv6 with non special schema port, as hostname', () => {
+      const req = request();
+      req.header.host = '[2001:cdba:0000:0000:0000:0000:3257:9652]:1337';
+      assert.equal(req.hostname, '[2001:cdba::3257:9652]');
+    });
+  });
+
   describe('when X-Forwarded-Host is present', () => {
     describe('and proxy is not trusted', () => {
       it('should be ignored', () => {