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    0.7.0 • Public • Published

    PG PubSub

    A Publish/Subscribe implementation on top of PostgreSQL NOTIFY/LISTEN

    Linting Build Status Node CI Build Status Known Vulnerabilities js-semistandard-style


    npm install pg-pubsub --save


    • Node.js ^14.17.0 || >=16.0.0
    • Postgres >= 9.4


    const PGPubsub = require('pg-pubsub');
    const pubsubInstance = new PGPubsub(uri[, options]);


      [log]: Function // default: silent when NODE_ENV=production, otherwise defaults to console.log(...)


    • addChannel(channelName[, eventListener]) – starts listening on a channel and optionally adds an event listener for that event. As PGPubsub inherits from EventEmitter one can also add it oneself. Returns a Promise that resolves when the listening has started.
    • removeChannel(channelName[, eventListener]) – either removes all event listeners and stops listeneing on the channel or removes the specified event listener and stops listening on the channel if that was the last listener attached.
    • publish(channelName, data) – publishes the specified data JSON-encoded to the specified channel. It may be better to do this by sending the NOTIFY channelName, '{"hello":"world"}' query yourself using your ordinary Postgres pool, rather than relying on the single connection of this module. Returns a Promise that will become rejected or resolved depending on the success of the Postgres call.
    • close(): Promise – closes down the database connection and removes all listeners. Useful for graceful shutdowns.
    • All EventEmitter methods are inherited from EventEmitter



    const pubsubInstance = new PGPubsub('postgres://username@localhost/database');
    await pubsubInstance.addChannel('channelName', function (channelPayload) {
      // Process the payload – if it was JSON that JSON has been parsed into an object for you
    await pubsubInstance.publish('channelName', { hello: "world" });

    The above sends NOTIFY channelName, '{"hello":"world"}' to PostgreSQL, which will trigger the above listener with the parsed JSON in channelPayload.


    const pubsubInstance = new PGPubsub('postgres://username@localhost/database');
    await pubsubInstance.addChannel('channelName');
    // pubsubInstance is a full EventEmitter object that sends events on channel names
    pubsubInstance.once('channelName', channelPayload => {
      // Process the payload


    Creating a PGPubsub instance will not do much up front. It will prepare itself to start a Postgres connection once the first channel is added and then it will keep a connection open until its shut down, reconnecting it if it gets lost, so that it can constantly listen for new notifications.

    Lint / Test

    • setup a postgres database to run the integration tests
      • the easist way to do this is via docker, docker run -it -p 5432:5432 -e POSTGRES_DB=pgpubsub_test postgres
    • npm test

    For an all-in-one command, try:

    # fire up a new DB container, run tests against it, and clean it up!
    docker rm -f pgpubsub_test || true && \
    docker run -itd -p 5432:5432 -e POSTGRES_DB=pgpubsub_test --name pgpubsub_test postgres && \
    npm test && \
    docker rm -f pgpubsub_test




    npm i pg-pubsub

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