Neo4j Graphql Skill

npm install @neo4j/graphql neo4j-driver graphql @apollo/server

npm install ws graphql-ws express body-parser cors

import { ApolloServer } from '@apollo/server';
import { startStandaloneServer } from '@apollo/server/standalone';
import { Neo4jGraphQL } from '@neo4j/graphql';
import neo4j from 'neo4j-driver';

const typeDefs = `#graphql
  type Movie @node {
    id: ID! @id
    title: String!
    actors: [Person!]! @relationship(type: "ACTED_IN", direction: IN)
  }

  type Person @node {
    id: ID! @id
    name: String!
    movies: [Movie!]! @relationship(type: "ACTED_IN", direction: OUT)
  }
`;

const driver = neo4j.driver(
  process.env.NEO4J_URI,
  neo4j.auth.basic(process.env.NEO4J_USERNAME, process.env.NEO4J_PASSWORD)
);

const neoSchema = new Neo4jGraphQL({ typeDefs, driver });

// assertIndexesAndConstraints syncs @id → UNIQUE constraints; wrap in try/catch
await neoSchema.assertIndexesAndConstraints({ options: { create: true } });

const server = new ApolloServer({ schema: await neoSchema.getSchema() });

const { url } = await startStandaloneServer(server, {
  context: async ({ req }) => ({ token: req.headers.authorization }),
  listen: { port: 4000 },
});

type Product @node {
  id: ID! @id
  name: String!
}

# Custom label (default = type name)
type Article @node(labels: ["Post", "Content"]) {
  title: String!
}

type Person @node {
  # direction: OUT = (this)-[:KNOWS]->(other)
  friends: [Person!]! @relationship(type: "KNOWS", direction: OUT)

  # direction: IN = (other)-[:ACTED_IN]->(this)
  actedIn: [Movie!]! @relationship(type: "ACTED_IN", direction: IN)

  # direction: UNDIRECTED = matches both directions (use sparingly — double-counts)
  colleagues: [Person!]! @relationship(type: "COLLEAGUE_OF", direction: UNDIRECTED)

  # Relationship with properties — reference an @relationshipProperties interface
  reviews: [Movie!]! @relationship(type: "REVIEWED", direction: OUT, properties: "ReviewedProps")
}

interface ReviewedProps @relationshipProperties {
  rating: Int!
  date: Date
}

query {
  movies(where: { title: { eq: "The Matrix" } }) {
    title
    actorsConnection {
      edges {
        properties { role }   # maps to @relationshipProperties interface
        node { name }
      }
    }
  }
}

type Person @node {
  name: String!

  # columnName must exactly match the RETURN alias — mismatch returns null silently
  friendCount: Int
    @cypher(
      statement: "MATCH (this)-[:KNOWS]->(f:Person) RETURN count(f) AS friendCount"
      columnName: "friendCount"
    )

  recommendedMovies: [Movie!]!
    @cypher(
      statement: """
        MATCH (this)-[:WATCHED]->(m:Movie)<-[:WATCHED]-(o:Person)-[:WATCHED]->(rec:Movie)
        WHERE NOT (this)-[:WATCHED]->(rec)
        RETURN rec
      """
      columnName: "rec"
    )
}

# @cypher on Query field — custom top-level query
type Query {
  topRatedMovies(limit: Int = 10): [Movie!]!
    @cypher(
      statement: "MATCH (m:Movie) WHERE m.rating IS NOT NULL RETURN m ORDER BY m.rating DESC LIMIT $limit"
      columnName: "m"
    )
}

# extend type adds computed fields without modifying the base type definition
extend type Movie @node {
  avgRating: Float
    @cypher(statement: "MATCH (this)<-[r:RATED]-(:User) RETURN avg(r.rating) AS result", columnName: "result")

  # Field arguments passed as Cypher params; always provide default to avoid null
  recommended(limit: Int = 3): [Movie!]!
    @cypher(
      statement: "MATCH (this)<-[:RATED]-(u:User)-[:RATED]->(rec:Movie) WITH rec, COUNT(u) AS score ORDER BY score DESC RETURN rec LIMIT $limit"
      columnName: "rec"
    )
}

type Post @node {
  id: ID! @id                          # auto-generates UUID; creates UNIQUE constraint
  createdAt: DateTime! @timestamp(operations: [CREATE])
  updatedAt: DateTime @timestamp(operations: [CREATE, UPDATE])
  title: String!
}

type User @node {
  id: ID! @id
  email: String! @alias(property: "emailAddress")  # GraphQL: email → DB: emailAddress
}

// Symmetric secret
const neoSchema = new Neo4jGraphQL({
  typeDefs,
  driver,
  features: {
    authorization: { key: process.env.JWT_SECRET },
  },
});

// JWKS endpoint (production)
const neoSchema = new Neo4jGraphQL({
  typeDefs,
  driver,
  features: {
    authorization: {
      key: { url: 'https://myapp.com/.well-known/jwks.json' },
    },
  },
});

context: async ({ req }) => ({ token: req.headers.authorization }),
// Or pass pre-decoded JWT:
context: async ({ req }) => ({ jwt: myDecodeJwt(req.headers.authorization) }),

# Require auth on all operations for a type
type Post @node
  @authentication
  @authorization(filter: [{ where: { node: { author: { id: { eq: "$jwt.sub" } } } } }]) {
  title: String!
  author: User! @relationship(type: "AUTHORED", direction: IN)
}

# requireAuthentication: false = allow public access without JWT
type Article @node
  @authorization(filter: [
    { requireAuthentication: false, where: { node: { published: { eq: true } } } }
    { where: { node: { author: { id: { eq: "$jwt.sub" } } } } }
  ]) {
  title: String!
  published: Boolean!
}

# validate (throws error) vs filter (silently hides data)
type BankAccount @node
  @authorization(validate: [{
    when: [BEFORE],
    where: { node: { owner: { id: { eq: "$jwt.sub" } } } }
  }]) {
  balance: Float!
}

# Role-based with custom JWT claims
type JWT @jwt {
  roles: [String!]! @jwtClaim(path: "myApp.roles")
}

type AdminReport @node
  @authentication(operations: [READ], jwt: { roles: { includes: "admin" } }) {
  data: String!
}

# v7: explicit eq required
query {
  movies(where: { title: { eq: "The Matrix" } }) {
    title
    actors { name }
  }
}

# Sort and paginate (v7: direct args, not options wrapper)
query {
  movies(sort: [{ title: ASC }], limit: 10, offset: 0) {
    title
  }
}

mutation {
  createMovies(input: [{
    title: "Inception"
    actors: {
      create: [{ node: { name: "Leonardo DiCaprio" } }]
      connect: { where: { node: { name: { eq: "Joseph Gordon-Levitt" } } } }
    }
  }]) {
    movies { id title }
  }
}

import { OGM } from '@neo4j/graphql-ogm';

const ogm = new OGM({ typeDefs, driver });
await ogm.init();  // must await before using models

const Movie = ogm.model('Movie');

// find
const movies = await Movie.find({
  where: { title: { eq: 'The Matrix' } },
  selectionSet: `{ id title actors { name } }`,
});

// create
const { movies: created } = await Movie.create({
  input: [{ title: 'Dune', actors: { create: [{ node: { name: 'Timothée Chalamet' } }] } }],
});

// update
await Movie.update({
  where: { id: { eq: movieId } },
  update: { title: { set: 'Dune: Part One' } },
});

// delete
await Movie.delete({ where: { id: { eq: movieId } } });

const neoSchema = new Neo4jGraphQL({
  typeDefs,
  driver,
  features: { subscriptions: true },
});

subscription {
  movieCreated(where: { title: { eq: "The Matrix" } }) {
    createdMovie { title }
  }
}
# Also: movieUpdated, movieDeleted

type ReadOnlyData @node @mutation(operations: []) { value: String! }  # disable mutations

type HeavyDoc @node {
  id: ID! @id
  content: String! @filterable(byValue: false) @sortable(enabled: false)  # perf guard
  title: String!
}

type Series @node @plural(value: "seriesList") { title: String! }  # irregular plural fix