[dart:io] Ignore server http upgrade request unless status code is right

sdk/lib/io/http_parser.dart

Index: sdk/lib/io/http_parser.dart
diff --git a/sdk/lib/io/http_parser.dart b/sdk/lib/io/http_parser.dart
index dc397c3c1782daadd86fc3219b86b5a488aaaff8..98c19d1f56996be48642e56d4c5e4b3820c7c252 100644
--- a/sdk/lib/io/http_parser.dart
+++ b/sdk/lib/io/http_parser.dart
@@ -664,9 +664,15 @@ class _HttpParser extends Stream<_HttpIncoming> {
             }
             if (headerField == "connection") {
               List<String> tokens = _tokenizeFieldValue(headerValue);
+              final bool isResponse = _messageType == _MessageType.RESPONSE;
+              final bool isUpgradeCode =
+                  _statusCode == HttpStatus.UPGRADE_REQUIRED ||
+                      _statusCode == HttpStatus.SWITCHING_PROTOCOLS;

[siva, 2017/08/07 21:30:19]

Not sure about Dart coding standards but would make sense to add parens around
the conditions for better readability
(_statusCode == ...) || (_statusCode == ...)

[zra, 2017/08/07 22:09:04]

Couldn't find any guidance in the style guide, but I added the parens for
grouping.

               for (int i = 0; i < tokens.length; i++) {
-                if (_caseInsensitiveCompare(
-                    "upgrade".codeUnits, tokens[i].codeUnits)) {
+                final bool isUpgrade = _caseInsensitiveCompare(
+                    "upgrade".codeUnits, tokens[i].codeUnits);
+                if ((isUpgrade && !isResponse) ||
+                    (isUpgrade && isResponse && isUpgradeCode)) {
                   _connectionUpgrade = true;
                 }
                 _headers._add(headerField, tokens[i]);