Registry / database / graphql-postgres-subscriptions

graphql-postgres-subscriptions

library1.0.5jsnpmunverified

GraphQL subscriptions implementation using PostgreSQL's LISTEN/NOTIFY and apollo's graphql-subscriptions. Stable version 1.0.5, not actively maintained (last release 2019). Supports multiple subscription manager instances by leveraging Postgres pub/sub mechanism. Implements PubSubEngine and AsyncIterator interfaces. Compared to graphql-redis-subscriptions, it uses no additional infrastructure beyond Postgres. Limited to single-node Postgres; does not support horizontal scaling natively. Peer dependency graphql supports ^0.10.5 to ^14.0.0. Node >=6 required.

database messaging

npm install graphql-postgres-subscriptions

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · GRAPHQL-POSTGRES-S

graphql-postgres-subscriptions

databasejavascriptv1.0.5

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

PostgresPubSub

✓ import { PostgresPubSub } from 'graphql-postgres-subscriptions'

✗ const PostgresPubSub = require('graphql-postgres-subscriptions')

ESM default export is not available; named import is correct. CommonJS users need const { PostgresPubSub } = require('graphql-postgres-subscriptions')

PostgresPubSub

✓ const { PostgresPubSub } = require('graphql-postgres-subscriptions')

✗ const PostgresPubSub = require('graphql-postgres-subscriptions').default

Do not use .default; package does not export default.

PostgresPubSub (with connection options)

✓ const pubsub = new PostgresPubSub({ client, commonMessageHandler })

✗ const pubsub = new PostgresPubSub(client, commonMessageHandler)

First argument must be an options object, not a client directly. Second argument is commonMessageHandler inside options object.

Creates a PostgresPubSub instance with a pg.Client, then publishes and subscribes to events using LISTEN/NOTIFY.

import { PostgresPubSub } from 'graphql-postgres-subscriptions'; import { Client } from 'pg'; const client = new Client(); await client.connect(); const pubsub = new PostgresPubSub({ client }); // Publish and subscribe example await pubsub.publish('POST_CREATED', { id: 1, title: 'Hello' }); const subscription = await pubsub.subscribe('POST_CREATED', (payload) => { console.log('Received:', payload); }); // Later: await subscription.unsubscribe();

Debug

Known issues

breakingDo not pass a client from pg.Pool to PostgresPubSub. Pool clients are shared and may miss NOTIFY messages.

fix

Create a dedicated pg.Client (not from Pool) and pass that to PostgresPubSub.

affects: all

gotchaPostgresPubSub uses LISTEN/NOTIFY which has a payload limit of 8000 bytes. Larger payloads throw an error.

fix

Keep published payloads under 8000 bytes, or use a separate mechanism for large payloads.

affects: all

gotchaClient must be connected before creating PostgresPubSub; otherwise subscribe will fail.

fix

Always await client.connect() before creating PostgresPubSub.

affects: all

deprecatedPackage uses deprecated graphql-subscriptions API (e.g., PubSubEngine). Consider migrating to graphql-subscriptions v2 or newer.

fix

Upgrade to graphql-subscriptions v2 and check for API changes.

affects: >=1.0.0

Errors

Common errors & fixes

error: payload string too long

Postgres LISTEN/NOTIFY payload limit is 8000 bytes. Published message exceeds limit.

fix

Reduce payload size below 8000 bytes, or split message into multiple publishes.

TypeError: client is not a connection

Passed a client from pg.Pool instead of a dedicated pg.Client.

fix

Create a new Client instance and connect it: const client = new Client(); await client.connect();

Module not found: Can't resolve 'graphql-subscriptions'

Missing peer dependency graphql-subscriptions.

fix

Install graphql-subscriptions: npm install graphql-subscriptions

Upgrade

Version history

1.0.5latest on npm

Audit

Dependencies

graphql-subscriptionsrequiredProvides PubSubEngine interface and AsyncIterator that this library implements

graphqloptionalPeer dependency for GraphQL subscriptions types

pgoptionalUsed to connect to PostgreSQL and listen for NOTIFY messages

Agent activity

19 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/GraphQLCollege/graphql-postgres-subscriptions ↗

packagegraphql-postgres-subscriptions ↗

homepagehttps://github.com/GraphQLCollege/graphql-postgres-subscriptions#readme ↗