postgraphile-plugin-subscriptions v1.0.0-alpha.5

Postgraphile Subscription Plugin

This plugin adds subscriptions by default per table in your postGraphile schema; e.g. user table gets subscription as onAllUsersMutation and depending on primary/unique keys onUserMutationById && onUserMutationByEmail. This plugin is not dependent on @graphile/supporter or @graphile/pro package. It uses graphql-subscriptions internally.

Postgraphile does not have build-in subscriptions so currently this plugin can be used with apollo-server, as it has built-in subscriptions. Check out example for more info.

This is currently in alpha stage and has few issues which would resolved in near future.

Features

With each mutation on table subscription returns following graphql result

• clientMutationId: Exact clientMutationId used while performing mutation.
• mutation: Type or mutation, value can be CREATED, UPDATED or DELETED.
• node: Updated values for record after performing mutation.
• previousValues: Previous values for record before performing mutation.
• changedFields: List of column names affected due to mutation.
• Allows subscribing to single record
• Allows subscribing to specific mutation.

Install

For npm

npm install postgraphile-plugin-subscriptions --save

For yarn

yarn add postgraphile-plugin-subscriptions

Usage

Postgres Database

Create table

CREATE TABLE "users"(
  "id" UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  "email" TEXT NOT NULL unique,
  "firstName" TEXT,
  "lastName" TEXT,
  "mobile" TEXT,
  "role" USER_ROLE NOT NULL,
  "createdAt" TIMESTAMPTZ DEFAULT now(),
  "updatedAt" TIMESTAMPTZ DEFAULT now(),
  "archivedAt" TIMESTAMPTZ
);

Server

Create apollo server and add postgraphile schema

const pg = require("pg");
const { ApolloServer } = require("apollo-server");
const { makeSchemaAndPlugin } = require("postgraphile-apollo-server");
const PgSubscriptionsPlugin = require("postgraphile-plugin-subscriptions");

const pgPool = new pg.Pool({
  connectionString: process.env.DATABASE_URL
});

async function main() {
  const { schema, plugin } = await makeSchemaAndPlugin(
    pgPool,
    'public',
    {
      appendPlugins: [
        PgSubscriptionsPlugin
      ],
    }
  );

  const server = new ApolloServer({
    schema,
    plugins: [plugin],
    tracing: true,
    debug: true
  });

  const { url } = await server.listen();
  console.log(`🚀 Server ready at ${url}`);
}

main().catch(e => {
  console.error(e);
  process.exit(1);
});

Client or GraphQL Playground

Subscribe to onAllUsersMutation (this will be triggered when any user is created, updated or deleted)

subscription {
  onAllUsersMutation {
    clientMutationId
    mutation
    user {
      id
      firstName
      lastName
      email
      updatedAt
      createdAt
    }
    previousValues {
      id
      firstName
      lastName
      email
      updatedAt
      createdAt
    }
    changedFields 
  }
}

Perform Mutation

mutation {
  updateUserById(input: {
    clientMutationId: "my_custom_mutation_id"
    id: "e673ad33-dbd7-45a7-b272-3fefa25b4cba"
    userPatch: {
      firstName: "John",
      lastName: "Doe",
      email:"john@example.com",
    }
  }) {
    clientMutationId
    user {
      id
    }
  }
}

Subscription Output

{
  "data": {
    "onAllUsersMutation": {
      "clientMutationId": "my_custom_mutation_id",
      "mutation": "UPDATED",
      "user": {
        "id": "e673ad33-dbd7-45a7-b272-3fefa25b4cba",
        "firstName": "John",
        "lastName": "Doe",
        "email": "john@example.com",
        "updatedAt": "Mon Dec 24 2018 12:55:20 GMT+0530 (GMT+05:30)",
        "createdAt": "Mon Dec 24 2018 12:50:14 GMT+0530 (GMT+05:30)"
      },
      "previousValues": {
        "id": "e673ad33-dbd7-45a7-b272-3fefa25b4cba",
        "firstName": "Jen",
        "lastName": "Doe",
        "email": "jen@example.com",
        "updatedAt": "Mon Dec 24 2018 12:50:14 GMT+0530 (GMT+05:30)",
        "createdAt": "Mon Dec 24 2018 12:50:14 GMT+0530 (GMT+05:30)"
      },
      "changedFields": [
        "firstName",
        "email"
        "updatedAt"
      ]
    }
  }
}

Subscribing to specific record

This will trigger only if user with email "jen@example.com" is updated or deleted.

subscription {
  onUserMutationByEmail(input: { 
    email:"jen@example.com" 
  }) {
   clientMutationId
    mutation
    user {
      id
      firstName
      lastName
      email
      updatedAt
      createdAt
    }
    previousValues {
      id
      firstName
      lastName
      email
      updatedAt
      createdAt
    }
    changedFields 
  }
}

Subscribing to specific events

This will trigger if any user is created or updated, but not if deleted.

subscription {
  onUserMutationByEmail(input: { 
    mutation_in: [
      CREATED
      UPDATED
    ]
  }) {
   clientMutationId
    mutation
    user {
      id
      firstName
      lastName
      email
      updatedAt
      createdAt
    }
    previousValues {
      id
      firstName
      lastName
      email
      updatedAt
      createdAt
    }
    changedFields 
  }
}

Subscribing to specific events of specific record

This will only trigger when user with id "e673ad33-dbd7-45a7-b272-3fefa25b4cba" is updated.

subscription {
  onUserMutationByEmail(input: {
    id: "e673ad33-dbd7-45a7-b272-3fefa25b4cba", 
    mutation_in: [
      UPDATED
    ]
  }) {
   clientMutationId
    mutation
    user {
      id
      firstName
      lastName
      email
      updatedAt
      createdAt
    }
    previousValues {
      id
      firstName
      lastName
      email
      updatedAt
      createdAt
    }
    changedFields 
  }
}