pg-notify
> Postgres PubSub client using NOTIFY/LISTEN
## Features
- Auto reconnect
- Payload size validation
- Channel and payload sanitization
## Install
```sh
npm install pg-notify
```
```sh
yarn add pg-notify
```
```sh
pnpm add pg-notify
```
## Usage
> PGPubSub accepts the same config as [pg](https://github.com/brianc/node-postgres).
```js
import PGPubSub from 'pg-notify'
//const PGPubSub = require('pg-notify')
;(async () => {
const pubsub = new PGPubSub({
connectionString: 'postgres://postgres:postgres@localhost:5432/db'
})
await pubsub.connect()
await pubsub.on('test', (payload) => {
console.log('payload: ', payload)
})
await pubsub.emit('test', 'this is the payload')
await pubsub.emit('test', { foo: 'bar' })
await pubsub.close()
})()
```
## API
### new PubSub(options)
- `options` (`object`) Configuration options for pg-notify pubsub instance. Accepts same options as [pg](https://github.com/brianc/node-postgres) with few custom ones described below.
- reconnectMaxRetries (`number`) Maximum number of reconnect attempts after losing connection. Pass `0` to disable reconnecting. Default: `10`.
- maxPayloadSize (`number`) Maximum payload size, exceeding given size will throw an error. Default: `7999` ([In the default configuration it must be shorter than 8000 bytes.](https://www.postgresql.org/docs/current/sql-notify.html)).
### emit(channel, payload)
- `channel` (`string`)
- `payload` (`string` or `object`)
### on(channel, listener)
- `channel` (`string`)
- `listener` (`function` accepting single argument `payload`)
### removeListener(listener)
- `listener` (`function` accepting single argument `payload`)
### close()
### connect()
## Contributing
Contributions, issues and feature requests are welcome!
## License
Copyright © 2020 [Aldis Ameriks](https://github.com/aldis-ameriks).
This project is [MIT](https://github.com/aldis-ameriks/pg-notify/blob/main/LICENSE) licensed.