@n1ru4l/in-memory-live-query-store

@n1ru4l/in-memory-live-query-store

A GraphQL live query store that tracks, invalidates and re-executes registered operations. Drop in replacement for graphql-js execute. Add live query capabilities to your existing GraphQL schema.

Check out the todo example server for a sample integration.

Install Instructions

yarn add -E @n1ru4l/in-memory-live-query-store

API

InMemoryLiveQueryStore

A InMemoryLiveQueryStore instance tracks, invalidates and re-executes registered live query operations.

The store will keep track of all root query field coordinates (e.g. Query.todos) and global resource identifiers (e.g. Todo:1). The store can than be notified to re-execute live query operations that select a given root query field or resource identifier by calling the invalidate method with the corresponding values.

A resource identifier is composed out of the typename and the actual resolved id value separated by a colon, but can be customized. For ensuring that the store keeps track of all your query resources you should always select the id field on your object types. The store will only keep track of fields with the name id and the type ID! (GraphQLNonNull(GraphQLID)).

import { InMemoryLiveQueryStore } from "@n1ru4l/in-memory-live-query-store";
import { parse, execute as executeImplementation } from "graphql";
import { schema } from "./schema";

const inMemoryLiveQueryStore = new InMemoryLiveQueryStore();

const rootValue = {
  todos: [
    {
      id: "1",
      content: "Foo",
      isComplete: false,
    },
  ],
};

const execute = inMemoryLiveQueryStore.makeExecute(executeImplementation);

execute({
  schema, // make sure your schema has the GraphQLLiveDirective from @n1ru4l/graphql-live-query
  operationDocument: parse(/* GraphQL */ `
    query todosQuery @live {
      todos {
        id
        content
        isComplete
      }
    }
  `),
  rootValue: rootValue,
  contextValue: {},
  variableValues: null,
  operationName: "todosQuery",
}).then(async (result) => {
  if (isAsyncIterable(result)) {
    for (const value of result) {
      console.log(value);
    }
  }
});

// Invalidate by resource identifier
rootValue.todos[0].isComplete = true;
inMemoryLiveQueryStore.invalidate(`Todo:1`);

// Invalidate by root query field coordinate
rootValue.todos.push({ id: "2", content: "Baz", isComplete: false });
inMemoryLiveQueryStore.invalidate(`Query.todos`);

The execute function returned from InMemoryLiveQueryStore.makeExecute is a drop-in replacement for the default execute function exported from graphql-js. You can provide your own execute function from any graphql-js version or other library.

Pass it to your favorite graphql transport that supports returning AsyncIterableIterator (or AsyncGenerator) from execute and thus delivering incremental query execution results.

List of known and tested compatible transports/servers:

Package	Transport	Version	Downloads
@n1ru4l/socket-io-graphql-server	WebSocket/HTTP Long Polling
graphql-helix	HTTP/SSE
graphql-ws	WebSocket

Recipes

Using with Redis

You can use Redis to synchronize invalidations across multiple instances.

import Redis from "ioredis";
import {
  InMemoryLiveQueryStore,
  InMemoryLiveQueryStoreParameter,
} from "@n1ru4l/in-memory-live-query-store";
import { ExecutionArgs, execute as defaultExecute } from "graphql";

const CHANNEL = "LIVE_QUERY_INVALIDATIONS";

export class RedisLiveQueryStore {
  pub: Redis.Redis;
  sub: Redis.Redis;
  liveQueryStore: InMemoryLiveQueryStore;

  constructor(redisUrl: string, parameter?: InMemoryLiveQueryStoreParameter) {
    this.pub = new Redis(redisUrl);
    this.sub = new Redis(redisUrl);
    this.liveQueryStore = new InMemoryLiveQueryStore(parameter);

    this.sub.subscribe(CHANNEL, (err) => {
      if (err) throw err;
    });

    this.sub.on("message", (channel, resourceIdentifier) => {
      if (channel === CHANNEL && resourceIdentifier)
        this.liveQueryStore.invalidate(resourceIdentifier);
    });
  }

  async invalidate(identifiers: Array<string> | string) {
    if (typeof identifiers === "string") {
      identifiers = [identifiers];
    }
    for (const identifier of identifiers) {
      this.pub.publish(CHANNEL, identifier);
    }
  }

  makeExecute(execute: typeof defaultExecute) {
    return this.liveQueryStore.makeExecute(args);
  }
}