Make IPv6 WebSocket work in Edge

WebSocket in IE and Edge does not understand IPv6 addresses because they
contain ':'. Which is an invalid symbol for UNC
https://en.wikipedia.org/wiki/IPv6_address#Literal_IPv6_addresses_in_UNC_path_names.
This caused `new WebSocket()` call to throw `SyntaxError` for all given
IPv6 addresses.

Following URL rewriting is needed to make WebSocket work with IPv6:
  1) replace all ':' with '-'
  2) replace '%' with 's' for link-local addresses
  3) append magic '.ipv6-literal.net' suffix

After such changes WebSocket in IE and Edge can connect to an IPv6
address.

This commit makes `WebSocketChannel` catch `SyntaxError` and rewrite
IPv6 address. It chooses not to detect browser/OS and things like this
upfront because it seems hard. User-agent string changes often and
differs for different versions of IE.

See following links for more details:
https://social.msdn.microsoft.com/Forums/ie/en-US/06cca73b-63c2-4bf9-899b-b229c50449ff/whether-ie10-websocket-support-ipv6?forum=iewebdevelopment
https://www.itdojo.com/ipv6-addresses-and-unc-path-names-overcoming-illegal/
https://en.wikipedia.org/wiki/IPv6_address#Literal_IPv6_addresses_in_UNC_path_names

Author: lutovich

src/v1/internal/ch-websocket.js

@@ -52,8 +52,8 @@ class WebSocketChannel {
         return;
       }
     }
-    this._url = scheme + '://' + config.url.hostAndPort;
-    this._ws = new WebSocket(this._url);
+
+    this._ws = createWebSocket(scheme, config.url);
     this._ws.binaryType = "arraybuffer";
 
     let self = this;
@@ -169,4 +169,55 @@ class WebSocketChannel {
 let available = typeof WebSocket !== 'undefined';
 let _websocketChannelModule = {channel: WebSocketChannel, available: available};
 
+function createWebSocket(scheme, parsedUrl) {
+  const url = scheme + '://' + parsedUrl.hostAndPort;
+
+  try {
+    return new WebSocket(url);
+  } catch (error) {
+    if (isIPv6AddressIssueOnWindows(error, parsedUrl)) {
+
+      // WebSocket in IE and Edge browsers on Windows do not support regular IPv6 address syntax because they contain ':'.
+      // It's an invalid character for UNC (https://en.wikipedia.org/wiki/IPv6_address#Literal_IPv6_addresses_in_UNC_path_names)
+      // and Windows requires IPv6 to be changes in the following way:
+      //   1) replace all ':' with '-'
+      //   2) replace '%' with 's' for link-local address
+      //   3) append '.ipv6-literal.net' suffix
+      // only then resulting string can be considered a valid IPv6 address. Yes, this is extremely weird!
+      // For more details see:
+      //   https://social.msdn.microsoft.com/Forums/ie/en-US/06cca73b-63c2-4bf9-899b-b229c50449ff/whether-ie10-websocket-support-ipv6?forum=iewebdevelopment
+      //   https://www.itdojo.com/ipv6-addresses-and-unc-path-names-overcoming-illegal/
+      // Creation of WebSocket with unconverted address results in SyntaxError without message or stacktrace.
+      // That is why here we "catch" SyntaxError and rewrite IPv6 address if needed.
+
+      const windowsFriendlyUrl = asWindowsFriendlyIPv6Address(scheme, parsedUrl);
+      return new WebSocket(windowsFriendlyUrl);
+    } else {
+      throw error;
+    }
+  }
+}
+
+function isIPv6AddressIssueOnWindows(error, parsedUrl) {
+  return error.name === 'SyntaxError' && isIPv6Address(parsedUrl);
+}
+
+function isIPv6Address(parsedUrl) {
+  const hostAndPort = parsedUrl.hostAndPort;
+  return hostAndPort.charAt(0) === '[' && hostAndPort.indexOf(']') !== -1;
+}
+
+function asWindowsFriendlyIPv6Address(scheme, parsedUrl) {
+  // replace all ':' with '-'
+  const hostWithoutColons = parsedUrl.host.replace(new RegExp(':', 'g'), '-');
+
+  // replace '%' with 's' for link-local IPv6 address like 'fe80::1%lo0'
+  const hostWithoutPercent = hostWithoutColons.replace('%', 's');
+
+  // append magic '.ipv6-literal.net' suffix
+  const ipv6Host = hostWithoutPercent + '.ipv6-literal.net';
+
+  return `${scheme}://${ipv6Host}:${parsedUrl.port}`;
+}
+
 export default _websocketChannelModule

test/internal/ch-websocket.test.js

@@ -0,0 +1,74 @@
+/**
+ * Copyright (c) 2002-2017 "Neo Technology,","
+ * Network Engine for Objects in Lund AB [http://neotechnology.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import wsChannel from '../../src/v1/internal/ch-websocket';
+import ChannelConfig from '../../src/v1/internal/ch-config';
+import urlUtil from '../../src/v1/internal/url-util';
+import {SERVICE_UNAVAILABLE} from '../../src/v1/error';
+
+describe('WebSocketChannel', () => {
+
+  const WebSocketChannel = wsChannel.channel;
+  const webSocketChannelAvailable = wsChannel.available;
+
+  let OriginalWebSocket;
+
+  beforeEach(() => {
+    if (webSocketChannelAvailable) {
+      OriginalWebSocket = WebSocket;
+    }
+  });
+
+  afterEach(() => {
+    if (webSocketChannelAvailable) {
+      WebSocket = OriginalWebSocket;
+    }
+  });
+
+  it('should fallback to literal IPv6 when SyntaxError is thrown', () => {
+    testFallbackToLiteralIPv6('bolt://[::1]:7687', 'ws://--1.ipv6-literal.net:7687');
+  });
+
+  it('should fallback to literal link-local IPv6 when SyntaxError is thrown', () => {
+    testFallbackToLiteralIPv6('bolt://[fe80::1%lo0]:8888', 'ws://fe80--1slo0.ipv6-literal.net:8888');
+  });
+
+  function testFallbackToLiteralIPv6(boltAddress, expectedWsAddress) {
+    if (!webSocketChannelAvailable) {
+      return;
+    }
+
+    // replace real WebSocket with a function that throws when IPv6 address is used
+    WebSocket = url => {
+      if (url.indexOf('[') !== -1) {
+        throw new SyntaxError();
+      }
+      return {url: url};
+    };
+
+    const url = urlUtil.parseBoltUrl(boltAddress);
+    // disable connection timeout, so that WebSocketChannel does not set any timeouts
+    const driverConfig = {connectionTimeout: 0};
+    const channelConfig = new ChannelConfig(url, driverConfig, SERVICE_UNAVAILABLE);
+    const webSocketChannel = new WebSocketChannel(channelConfig);
+
+    expect(webSocketChannel._ws.url).toEqual(expectedWsAddress);
+  }
+
+});