Webpack-dev-server: WebSocket transportMode is missing heartbeat

[ianschmitz]

• Operating System:
• Node Version: 10.18.1
• NPM Version: 6.13.4
• webpack Version: 4.41.5
• webpack-dev-server Version: 3.9.0
• Browser: Chrome 79

• [x] This is a bug
• [ ] This is a modification request

Expected Behavior

webpack-dev-server sends keep alive heartbeat when using transportMode: 'ws', consistent with sockjs-node to keep the connection open while developing.

Actual Behavior

WebSocket connection times out after a period of inactivity. A page refresh is needed to reconnect.

Create React App related issue: https://github.com/facebook/create-react-app/issues/8091

For Bugs; How can we reproduce the behavior?

Use transportMode: 'ws', connect to running webpack-dev-server instance, and wait for socket to timeout.

Here's the RFC for ping/pong in the WebSocket spec: https://tools.ietf.org/html/rfc6455#section-5.5.2

[alexander-akait]

/cc @Loonride

[alexander-akait]

Easy to implement - https://github.com/websockets/ws#how-to-detect-and-close-broken-connections, somebody want to be a champion?

[Loonride]

Easy to implement - https://github.com/websockets/ws#how-to-detect-and-close-broken-connections, somebody want to be a champion?

I can do this

[alexander-akait]

Client doesn't require additional code (browser automatically sends ping)