Add Windows named pipe support for client

[hyurl]

The WebSocket client has been supporting Unix socket for a long time, but lacks the support of Windows named pipe,
because in the previous versions, the URL constructor used to parse the address cannot parse a path in windows style,
and the following code will throw a TypeError:

const ws = new WebSocket("ws+unix://\\\\?\\pipe\\C:\\example.sock");

To implement full support of IPC, I added two more steps for parsing the address and setting the socket path for connection,
now the above code can work as expected.

[lpinca]

I'm not happy to skip the URL parser which is why there is no IPC support on Windows. This is not a valid URL.

[hyurl]

On second thought, I see your point, and such a URL does seem a little bit odd.

[lpinca]

Wouldn't index be incorrectly set to -1 if opts.path is something like '\\.\pipe\x:/foo'? '\\.\pipe\x' is a valid named pipe.

[lpinca]

@hyurl how about something like this:

diff --git a/lib/websocket.js b/lib/websocket.js
index ce6f34c..7ab8677 100644
--- a/lib/websocket.js
+++ b/lib/websocket.js
@@ -475,9 +475,9 @@ function initAsClient(websocket, address, protocols, options) {
     websocket.url = address;
   }
 
-  const isUnixSocket = parsedUrl.protocol === 'ws+unix:';
+  const isIPCUrl = parsedUrl.protocol === 'ws+unix:';
 
-  if (!parsedUrl.host && (!isUnixSocket || !parsedUrl.pathname)) {
+  if (!parsedUrl.host && (!isIPCUrl || !parsedUrl.pathname)) {
     throw new Error(`Invalid URL: ${websocket.url}`);
   }
 
@@ -528,11 +528,18 @@ function initAsClient(websocket, address, protocols, options) {
     opts.auth = `${parsedUrl.username}:${parsedUrl.password}`;
   }
 
-  if (isUnixSocket) {
-    const parts = opts.path.split(':');
+  if (isIPCUrl) {
+    if (opts.path.startsWith('\\\\.\\pipe\\', 1)) {
+      const [socketPath, path] = opts.path.split(':/');
 
-    opts.socketPath = parts[0];
-    opts.path = parts[1];
+      opts.socketPath = socketPath.slice(1);
+      opts.path = path ? `/${path}` : '/';
+    } else {
+      const [socketPath, path] = opts.path.split(':');
+
+      opts.socketPath = socketPath;
+      opts.path = path;
+    }
   }
 
   let req = (websocket._req = get(opts));

Limitations:

1. \\?\pipe\foo cannot be used but using \\.\pipe\foo to connect to \\?\pipe\foo works anyway so I think it's not a problem.
2. An additional / must be added after the protocol. For example: ws+unix:///\\.\pipe\foo:/pathname?bar=baz (this is a valid URL).

[hyurl]

@lpinca I was thinking about something like ws+unix:pathname?foo=bar (no //), which is valid for the URL constructor, for example:

const ws = new WebSocket("ws+unix:some.sock"); // this syntax should work both on Windows and Unix

const ws = new WebSocket("ws+unix:C:\\some.sock"); // this syntax only works on Windows

const ws = new WebSocket("ws+unix://some.sock"); // this syntax only works on Unix

All we have to do is adding \\?\pipe\ or \\.\pipe\ internally for the user.