docs: graphql schema stitching w neo4j-graphql-js

Author: roschaefer

example/schema-stitching/.env.test

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+JWT_SECRET='supersecret'
+NEO4J_USERNAME='neo4j'
+NEO4J_PASSWORD='letmein'
+NEO4J_PROTOCOL=neo4j
+NEO4J_HOST=localhost
+NEO4J_DATABASE=neo4j
+NEO4J_ENCRYPTION=ENCRYPTION_OFF

example/schema-stitching/.eslintrc.js

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+module.exports = {
+  plugins: ['jest'],
+  env: {
+    es6: true,
+    node: true,
+    'jest/globals': true
+  },
+  extends: 'airbnb-base',
+  globals: {
+    Atomics: 'readonly',
+    SharedArrayBuffer: 'readonly'
+  },
+  parserOptions: {
+    ecmaVersion: 2018,
+    sourceType: 'module'
+  },
+  rules: {
+    'jest/no-disabled-tests': 'warn',
+    'jest/no-focused-tests': 'error',
+    'jest/no-identical-title': 'error',
+    'jest/prefer-to-have-length': 'warn',
+    'jest/valid-expect': 'error',
+    'import/no-extraneous-dependencies': [
+      'error',
+      { devDependencies: ['db/**/*.js', '**/*.test.js', '**/*.spec.js'] }
+    ]
+  }
+};

example/schema-stitching/babel.config.js

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+module.exports = {
+  presets: [['@babel/preset-env', { targets: { node: 'current' } }]]
+};

example/schema-stitching/index.js

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+import { ApolloServer } from 'apollo-server';
+import Server from './src/server';
+
+const playground = {
+  settings: {
+    'schema.polling.enable': false
+  }
+};
+
+(async () => {
+  const server = await Server(ApolloServer, { playground });
+  const { url } = await server.listen();
+  // eslint-disable-next-line no-console
+  console.log(`🚀  Server ready at ${url}`);
+})();

example/schema-stitching/package.json

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+{
+  "name": "neo4j-graphql-js-example-schema-stitching",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "scripts": {
+    "lint": "eslint .",
+    "test": "jest",
+    "test:debug": "node inspect node_modules/jest/bin/jest.js",
+    "dev": "nodemon -r esm index.js",
+    "dev:debug": "nodemon inspect -r esm index.js",
+    "db:seed": "node -r esm src/db/seed.js",
+    "db:clean": "node -r esm src/db/clean.js"
+  },
+  "dependencies": {
+    "@graphql-tools/delegate": "^7.0.7",
+    "@graphql-tools/graphql-file-loader": "^6.2.6",
+    "@graphql-tools/load": "^6.2.5",
+    "@graphql-tools/schema": "^7.1.2",
+    "@graphql-tools/stitch": "^7.1.4",
+    "@graphql-tools/wrap": "^7.0.4",
+    "apollo-datasource": "^0.7.2",
+    "apollo-server": "^2.19.0",
+    "bcrypt": "^5.0.0",
+    "dotenv-flow": "^3.2.0",
+    "graphql-tools": "^7.0.2",
+    "jsonwebtoken": "^8.5.1",
+    "neo4j-driver": "^4.2.1",
+    "neo4j-graphql-js": "^2.17.1",
+    "neode": "^0.4.6"
+  },
+  "devDependencies": {
+    "@babel/core": "^7.12.9",
+    "@babel/preset-env": "^7.12.7",
+    "apollo-server-testing": "^2.19.0",
+    "babel-eslint": "^10.1.0",
+    "babel-jest": "^26.6.3",
+    "eslint": "^7.14.0",
+    "eslint-config-airbnb-base": "^14.2.1",
+    "eslint-plugin-import": "^2.22.1",
+    "eslint-plugin-jest": "^24.1.3",
+    "esm": "^3.2.25",
+    "jest": "^26.6.3",
+    "nodemon": "^2.0.6"
+  }
+}

example/schema-stitching/src/config.js

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+require('dotenv-flow').config();
+
+export const { JWT_SECRET, NEO4J_USERNAME, NEO4J_PASSWORD } = process.env;
+if (!(JWT_SECRET && NEO4J_USERNAME && NEO4J_PASSWORD)) {
+  throw new Error(`
+
+Please create a .env file and configure environment variables there.
+
+You could e.g. copy the .env file used for testing:
+
+$ cp .env.text .env
+`);
+}
+export default { JWT_SECRET, NEO4J_USERNAME, NEO4J_PASSWORD };

example/schema-stitching/src/context.js

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+import jwt from 'jsonwebtoken';
+import driver from './driver';
+import { JWT_SECRET } from './config';
+
+export default function context({ req }) {
+  let token = req.headers.authorization || '';
+  token = token.replace('Bearer ', '');
+  const jwtSign = payload => jwt.sign(payload, JWT_SECRET);
+  try {
+    const decoded = jwt.verify(token, JWT_SECRET);
+    return { ...decoded, jwtSign, driver };
+  } catch (e) {
+    return { jwtSign, driver };
+  }
+}

example/schema-stitching/src/db/clean.js

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+import neode from './neode';
+
+(async () => {
+  await neode.driver
+    .session()
+    .writeTransaction(txc => txc.run('MATCH(n) DETACH DELETE n;'));
+  neode.driver.close();
+})();

example/schema-stitching/src/db/entities/Person.js

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+import bcrypt from 'bcrypt';
+import neode from '../neode';
+
+export default class Person {
+  constructor(data) {
+    Object.assign(this, data);
+  }
+
+  checkPassword(password) {
+    return bcrypt.compareSync(password, this.hashedPassword);
+  }
+
+  async save() {
+    this.hashedPassword = bcrypt.hashSync(this.password, 10);
+    const node = await neode.create('Person', this);
+    Object.assign(this, { ...node.properties(), node });
+    return this;
+  }
+
+  static async first(props) {
+    const node = await neode.first('Person', props);
+    if (!node) return null;
+    return new Person({ ...node.properties(), node });
+  }
+
+  static currentUser(context) {
+    const { person } = context;
+    if (!person) return null;
+    return Person.first({ id: person.id });
+  }
+
+  static async all() {
+    const nodes = await neode.all('Person');
+    return nodes.map(node => new Person({ ...node.properties(), node }));
+  }
+}

example/schema-stitching/src/db/entities/Post.js

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+import neode from '../neode';
+
+export default class Post {
+  constructor(data) {
+    Object.assign(this, data);
+  }
+
+  async save() {
+    if (!(this.author && this.author.node))
+      throw new Error('author node is missing!');
+    const node = await neode.create('Post', this);
+    await node.relateTo(this.author.node, 'wrote');
+    Object.assign(this, { ...node.properties(), node });
+    return this;
+  }
+}

example/schema-stitching/src/db/models/Person.js

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+module.exports = {
+  id: {
+    type: 'uuid',
+    primary: true
+  },
+  name: {
+    type: 'string',
+    required: true
+  },
+  email: {
+    type: 'string',
+    unique: true,
+    required: true
+  },
+  password: {
+    type: 'string',
+    strip: true
+  },
+  hashedPassword: {
+    type: 'string',
+    required: true
+  }
+};

example/schema-stitching/src/db/models/Post.js

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+module.exports = {
+  id: {
+    type: 'uuid',
+    primary: true
+  },
+  title: {
+    type: 'string',
+    required: true
+  },
+  text: 'string',
+  wrote: {
+    type: 'relationship',
+    target: 'Person',
+    relationship: 'WROTE',
+    direction: 'in'
+  }
+};

example/schema-stitching/src/db/neode.js

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+import Neode from 'neode';
+import '../config';
+
+const dir = `${__dirname}/models`;
+// eslint-disable-next-line new-cap
+const instance = new Neode.fromEnv().withDirectory(dir);
+export default instance;

example/schema-stitching/src/db/seed.js

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+import neode from './neode';
+import Person from './entities/Person';
+import Post from './entities/Post';
+
+const seed = async () => {
+  const alice = new Person({
+    name: 'Alice',
+    email: 'alice@example.org',
+    password: '1234'
+  });
+  const bob = new Person({
+    name: 'Bob',
+    email: 'bob@example.org',
+    password: '4321'
+  });
+  await Promise.all([alice, bob].map(p => p.save()));
+  const posts = [
+    new Post({ author: alice, title: 'Schema Stitching is cool!' }),
+    new Post({ author: alice, title: 'Neo4J is a nice graph database!' })
+  ];
+  await Promise.all(posts.map(post => post.save()));
+};
+
+(async () => {
+  await seed();
+  await neode.driver.close();
+})();

example/schema-stitching/src/driver.js

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+import neo4j from 'neo4j-driver';
+import { NEO4J_USERNAME, NEO4J_PASSWORD } from './config';
+
+const driver = neo4j.driver(
+  'bolt://localhost:7687',
+  neo4j.auth.basic(NEO4J_USERNAME, NEO4J_PASSWORD)
+);
+export default driver;

example/schema-stitching/src/neo4j-graphql-js/schema.js

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+import { makeAugmentedSchema } from 'neo4j-graphql-js';
+import { gql } from 'apollo-server';
+
+const typeDefs = gql`
+  type Person {
+    id: ID!
+    name: String!
+    email: String
+    posts: [Post] @relation(name: "WROTE", direction: "OUT")
+  }
+
+  type Post {
+    id: ID!
+    title: String!
+    text: String
+    author: Person @relation(name: "WROTE", direction: "IN")
+  }
+`;
+
+const schema = makeAugmentedSchema({ typeDefs });
+export default schema;

example/schema-stitching/src/resolvers.js

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+import { delegateToSchema } from '@graphql-tools/delegate';
+import {
+  AuthenticationError,
+  UserInputError,
+  ForbiddenError
+} from 'apollo-server';
+import Person from './db/entities/Person';
+import Post from './db/entities/Post';
+
+export default ({ subschema }) => ({
+  Query: {
+    profile: async (_parent, _args, context, info) => {
+      const [person] = await delegateToSchema({
+        schema: subschema,
+        operation: 'query',
+        fieldName: 'Person',
+        args: {
+          id: context.person.id
+        },
+        context,
+        info
+      });
+      return person;
+    }
+  },
+  Mutation: {
+    login: async (_parent, { email, password }, { jwtSign }) => {
+      const person = await Person.first({ email });
+      if (person && person.checkPassword(password)) {
+        return jwtSign({ person: { id: person.id } });
+      }
+      throw new AuthenticationError('Wrong email/password combination!');
+    },
+    signup: async (_parent, { name, email, password }, { jwtSign }) => {
+      const existingPerson = await Person.first({ email });
+      if (existingPerson) throw new UserInputError('email address not unique');
+      const person = new Person({ name, email, password });
+      await person.save();
+      return jwtSign({ person: { id: person.id } });
+    },
+    writePost: async (_parent, args, context, info) => {
+      const currentUser = await Person.currentUser(context);
+      if (!currentUser)
+        throw new ForbiddenError('You must be authenticated to write a post!');
+      const post = new Post({ ...args, author: currentUser });
+      await post.save();
+      const [resolvedPost] = await delegateToSchema({
+        schema: subschema,
+        operation: 'query',
+        fieldName: 'Post',
+        args: { id: post.id },
+        context,
+        info
+      });
+      return resolvedPost;
+    }
+  },
+  Person: {
+    email: {
+      selectionSet: '{ id }',
+      resolve: (parent, _args, context) => {
+        const { person } = context;
+        if (person && person.id === parent.id) return parent.email;
+        throw new ForbiddenError('E-Mail addresses are private');
+      }
+    },
+    postCount: {
+      selectionSet: '{ posts { id } }',
+      resolve: person => person.posts.length
+    }
+  }
+});