chrome-websockets-test

This repository reproduces a problem with the Chrome WebSocket constructor sending Sec-WebSocket-Protocol: undefined request headers even though the protocols argument is undefined.

Problem

The following WebSocket call succeeds:

new WebSocket('ws://localhost:3000', undefined);

All of the following WebSocket calls are failing:

new WebSocket('ws://localhost:3000', undefined, {});
new WebSocket('ws://localhost:3000', undefined, true);
new WebSocket('ws://localhost:3000', undefined, undefined, {});

The error we get is:

WebSocket connection to 'ws://localhost:3000' failed: Error during WebSocket handshake: Sent non-empty 'Sec-WebSocket-Protocol' header but no response was received

Analysis

Chrome sends a Sec-WebSocket-Protocol: undefined request header if the WebSocket constructor is called with more than two parameters of which at least one is undefined.

Chrome expects the server to acknowledge the protocol (which would be undefined) by providing the same header in the response. Some server implementations won't send the Sec-WebSocket-Protocol and as a result, the 101 handshake fails with the error message mentioned above.

Demo

npm run server

> chrome-websockets-test@1.0.0 server /home/mischi/p/chrome-websockets-test
> node ./server.js

New connection established.
New connection: handleProtocols: Sec-WebSocket-Protocol request header was [ 'undefined' ]
New connection established.

npm test

> chrome-websockets-test@1.0.0 test /home/mischi/p/chrome-websockets-test
> node ./test.js

Should pass WebSocket connection is open.
Should fail WebSocket connection failed to open.
The connection was closed abnormally, e.g., without sending or receiving a Close control frame

Process finished with exit code 0

References

• https://www.w3.org/TR/websockets/#the-websocket-interface