[NIFI-3318] Send message from PutWebSocket to all connected clients

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.2.0
• Component/s: Extensions
• Assignee: Jeremy Dyer
• Reporter: Koji Kawamura
• Created: 11/Jan/17 01:16
• Updated: 20/Apr/17 23:29
• Resolved: 20/Apr/17 23:25

Description

Currently, PutWebSocket processor needs an incoming flow file having a WebSocket session id attribute to tell the NiFi WebSocket server which connected client to send a message to.

A flow explained in this Gist to pull messages from Kafka then send it back to multiple connected clients works, but it keeps flow files floating around in the loop, and basically too difficult to setup. Also, it imposes unnecessary latency because it needs to poll a cache to see if there's new message.

The list of connected session ids are kept in WebSocket server controller service, so it's possible to loop through those sessions in controller service without passing a specific session id from PutWebSocket processor.
PutWebSocket processor can be improved so that it can send messages to every connected client.

Issue Links

• links to: GitHub Pull Request #1649