This project is deprecated/obsolete. Please see https://docs.harperdb.io/docs/developers/real-time#websockets for information on how to use HarperDB's native support for websockets.
This project is built on specific internal APIs in HarperDB 4.0/4.1 as a demonstration of real-time capabilities, but is NOT compatible with HarperDB 4.2+, which has native real-time capabilities that should be used instead of project. Please use visit the real-time documentation for how to use real-time capabilities like WebSockets, SSE, and MQTT.
HarperDB's WebSocket Custom Function to connect to the internal NATS.io stream and subscribe to real-time database transactions.
- Create a HarperDB Instance with Clustering Enabled
- Clone this repo to the $hdb/custom_functions directory of your HarperDB instance.
- Copy config.json.example to config.json and update the params to match your environment (cert locations and cluster username)
- Run
npm install - Restart the CF
Ensure that the database schema and tables are created before subscribing to a schema.table pattern.
- Connect to the WebSocket server running at $hdb_cf_host/cf-template-websockets (by default this would be ws://localhost:9926/cf-template-websockets if it's running locally)
- Subscribe to a stream with a message like:
{
action: "subscribe",
schema: "dev",
table: "dog",
id: "*",
}
The id can be one matching a record (it's okay to subscribe to a specific record before it exists) or '*' which will subscribe to all record transactions on the given schema and table
There's an example client in the repo (client.example.js) that can be used as a starting point for subscribing.