draft-autosensing patch for ncr nodejs-websocket server

--- ws.js       2010-07-06 07:23:24.000000000 +0000
+++ ws_my.js    2010-07-07 09:33:39.000000000 +0000
@@ -12,16 +12,26 @@
   });
 }

-var sys = require("sys"),
-  net = require("net"),
-  headerExpressions = [
-    /^GET (\/[^\s]*) HTTP\/1\.1$/,
-    /^Upgrade: WebSocket$/,
-    /^Connection: Upgrade$/,
-    /^Host: (.+)$/,
-    /^Origin: (.+)$/
-  ],
-  handshakeTemplate = [
+function pack(num) {
+  var result = '';
+  result += String.fromCharCode(num >> 24 & 0xFF);
+  result += String.fromCharCode(num >> 16 & 0xFF);
+  result += String.fromCharCode(num >> 8 & 0xFF);
+  result += String.fromCharCode(num & 0xFF);
+  return result;
+}
+
+var sys  = require("sys"),
+  net    = require("net"),
+  crypto = require("crypto"),
+  requiredHeaders = {
+    'get': /^GET (\/[^\s]*)/,
+    'upgrade': /^WebSocket$/,
+    'connection': /^Upgrade$/,
+    'host': /^(.+)$/,
+    'origin': /^(.+)$/,
+  },
+  handshakeTemplate75 = [
     'HTTP/1.1 101 Web Socket Protocol Handshake',
     'Upgrade: WebSocket',
     'Connection: Upgrade',
@@ -30,13 +40,23 @@
     '',
     ''
   ].join("\r\n"),
+  handshakeTemplate76 = [
+    'HTTP/1.1 101 WebSocket Protocol Handshake', // note a diff here
+    'Upgrade: WebSocket',
+    'Connection: Upgrade',
+    'Sec-WebSocket-Origin: {origin}',
+    'Sec-WebSocket-Location: ws://{host}{resource}',
+    '',
+    '{data}'
+  ].join("\r\n"),
   policy_file = '<cross-domain-policy><allow-access-from domain="*" to-ports="*" /></cross-domain-policy>';

+
 exports.createServer = function (websocketListener) {
   return net.createServer(function (socket) {
     socket.setTimeout(0);
     socket.setNoDelay(true);
-    socket.setEncoding("utf8");
+    socket.setKeepAlive(true, 0);

     var emitter = new process.EventEmitter(),
       handshaked = false,
@@ -62,43 +82,95 @@
     }

     function handshake(data) {
-      var headers = data.split("\r\n");
+      var _headers = data.split("\r\n");

-      if(/<policy-file-request.*>/.exec(headers[0])) {
+      if ( /<policy-file-request.*>/.exec(_headers[0]) ) {
         socket.write(policy_file);
         socket.end();
         return;
       }

-      var matches = [], match;
-      for (var i = 0, l = headerExpressions.length; i < l; i++) {
-        match = headerExpressions[i].exec(headers[i]);
-
-        if (match) {
-          if(match.length > 1) {
-            matches.push(match[1]);
-          }
+      // go to more convenient hash form
+      var headers = {}, upgradeHead, len = _headers.length;
+      if ( _headers[0].match(/^GET /) ) {
+        headers["get"] = _headers[0];
+      } else {
+        socket.end();
+        return;
+      }
+      if ( _headers[ _headers.length - 1 ] ) {
+        upgradeHead = _headers[ _headers.length - 1 ];
+        len--;
+      }
+      while (--len) { // _headers[0] will be skipped
+        var header = _headers[len];
+        if (!header) continue;
+
+        var split = header.split(": ", 2); // second parameter actually seems to not work in node
+        headers[ split[0].toLowerCase() ] = split[1];
+      }
+
+      // check if we have all needed headers and fetch data from them
+      var data = {}, match;
+      for (var header in requiredHeaders) {
+        //           regexp                          actual header value
+        if ( match = requiredHeaders[ header ].exec( headers[header] ) ) {
+          data[header] = match;
         } else {
           socket.end();
           return;
         }
       }

-      socket.write(nano(handshakeTemplate, {
-        resource: matches[0],
-        host:     matches[1],
-        origin:   matches[2],
-      }));
+      // draft auto-sensing
+      if ( headers["sec-websocket-key1"] && headers["sec-websocket-key2"] && upgradeHead ) { // 76
+        var strkey1 = headers["sec-websocket-key1"]
+          , strkey2 = headers["sec-websocket-key2"]
+
+          , numkey1 = parseInt(strkey1.replace(/[^\d]/g, ""), 10)
+          , numkey2 = parseInt(strkey2.replace(/[^\d]/g, ""), 10)
+
+          , spaces1 = strkey1.replace(/[^\ ]/g, "").length
+          , spaces2 = strkey2.replace(/[^\ ]/g, "").length;
+
+        if (spaces1 == 0 || spaces2 == 0 || numkey1 % spaces1 != 0 || numkey2 % spaces2 != 0) {
+          socket.end();
+          return;
+        }
+
+        var hash = crypto.createHash("md5")
+        , key1 = pack(parseInt(numkey1/spaces1))
+        , key2 = pack(parseInt(numkey2/spaces2));
+
+        hash.update(key1);
+        hash.update(key2);
+        hash.update(upgradeHead);
+
+        socket.write(nano(handshakeTemplate76, {
+          resource: data.get[1],
+          host:     data.host[1],
+          origin:   data.origin[1],
+          data:     hash.digest("binary"),
+        }), "binary");
+
+      } else { // 75
+        socket.write(nano(handshakeTemplate75, {
+          resource: data.get[1],
+          host:     data.host[1],
+          origin:   data.origin[1],
+        }));
+
+      }

       handshaked = true;
-      emitter.emit("connect", matches[0]);
+      emitter.emit("connect", data.get[1]);
     }

     socket.addListener("data", function (data) {
       if(handshaked) {
-        handle(data);
+        handle(data.toString("utf8"));
       } else {
-        handshake(data);
+        handshake(data.toString("binary")); // because of draft76 handshakes
       }
     }).addListener("end", function () {
       socket.end();
@@ -127,7 +199,7 @@
         socket.end();
       }
     }
-
+
     emitter.end = function () {
       socket.end();
     }
@@ -135,3 +207,4 @@
     websocketListener(emitter); // emits: "connect", "data", "close", provides: write(data), end()
   });
 }
+

This looks cool.

re: #186 comment - I don't understand why it breaks the connection - it's exposed so user can call websocket.end() to close underlying connection from the server side. Does it cause problems?

btw. I think that the native http parser that comes with node started supporting Upgrade headers some time ago. Have you maybe checked it out? It seems it should render node.ws.js obsolete but I'm not sure - so little time, so much code to write ;)

In line 186 I was wrong - disconnect was caused by timeout in your example realisation :)

http.js is cool and used by miksago server, but it cant serve flash policy requests (or I just loose 3 workdays for nothing :) )

ok, so it seems there's still a place for this little lib. Can you send me a pull request?

I'll try :)