fix browser cookies crashing websocket connection

Author: ChrLackner

webgpu/jupyter.py

@@ -486,9 +486,7 @@ def Draw(
 
         def _webgpu_js(server):
             js = _link_js_code + """
-const __is_vscode = (typeof location !== 'undefined' && location.protocol === 'vscode-webview:');
-const __webgpu_host = __is_vscode ? '127.0.0.1' : ((typeof location !== 'undefined' && location.hostname) || '127.0.0.1');
-WebsocketLink('ws://' + __webgpu_host + ':{port}?token={token}');
+WebsocketLink('ws://127.0.0.1:{port}?token={token}');
 """.format(port=server.port, token=server.auth_token)
             display(Javascript(js))
 

webgpu/link/websocket.py

@@ -1,10 +1,20 @@
 import asyncio
 import json
+import os
 import secrets
 import threading
 from concurrent.futures import ThreadPoolExecutor
 from urllib.parse import parse_qs, urlparse
 
+# Browser WebSocket handshakes automatically attach cookies for the target
+# (loopback) host, and the JS WebSocket API exposes no way to omit them. On
+# machines with large cookies for localhost/127.0.0.1 the resulting Cookie
+# header line can exceed websockets' default 8192-byte limit, making the
+# handshake fail with SecurityError("line too long"). Raise the limit before
+# importing websockets (the value is read at import time of websockets.http11).
+# Note: only honored on websockets versions that support this env var.
+os.environ.setdefault("WEBSOCKETS_MAX_LINE_LENGTH", "32768")
+
 import websockets
 from websockets.http11 import Response
 from websockets.datastructures import Headers