GraphQL quick start

Run Memgraph

The easiest way to start Memgraph is by running Memgraph Platform Docker image with the following command:

docker run -p 7687:7687 -p 7444:7444 -p 3000:3000 --name memgraph memgraph/memgraph-platform

The command above will start Memgraph Platform, which includes Memgraph database, Memgraph Lab and Memgraph MAGE. Memgraph uses Bolt protocol to communicate with the client using the exposed 7687 port. Memgraph Lab is a web application you can use to visualize the data. It's accessible at http://localhost:3000 (opens in a new tab) if Memgraph Platform is running correctly. The 7444 port enables Memgraph Lab to access and preview the logs, which is why both of these ports need to be exposed.

For more information visit the getting started guide on how to run Memgraph with Docker.

Create a work directory

Next, create a directory for your project and positioning yourself in it:

mkdir graphql-example
cd graphql-example

Initialize the Node.js project

Initialize the project using the following code:

npm init es6 --yes

Setup the Neo4j GraphQL Library

Install the library and its dependencies by running the following command:

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

Create the application file

The application file will be used to setup the Neo4j GraphQL Library and connect to the running Memgraph instance.

Create the file and add the content below.

touch index.js

const { Neo4jGraphQL } = require("@neo4j/graphql");
const { ApolloServer, gql } = require("apollo-server");
const neo4j = require("neo4j-driver");
 
const typeDefs = gql`
type Post {
    id: ID! @id
    content: String!
    creator: User! @relationship(type: "HAS_POST", direction: IN)
}
 
type User {
    id: ID! @id
    name: String
    posts: [Post!]! @relationship(type: "HAS_POST", direction: OUT)
}
`;
 
const driver = neo4j.driver(
    "bolt://localhost:7687",
    neo4j.auth.basic("", "")
);
 
const neoSchema = new Neo4jGraphQL({
    typeDefs, driver,
    config: {
        driverConfig: {
            database: "memgraph",
        },
    }
});
 
neoSchema.getSchema().then((schema) => {
  const server = new ApolloServer({
      schema,
  });
 
  server.listen().then(({ url }) => {
      console.log(`🚀 Server ready at ${url}`);
  });
})

The example above shows that the data schema must be explicitly defined. The GraphQL server can only process queries that operate on data conforming to the specified schemas. In this example, the schema defines a graph, where the nodes labeled as User or Post may be connected with a HAS_POST relationship.

To set up a GraphQL client against a running Memgraph instance, you have to specify the GraphQL schema, set up the used drivers, and specify Memgraph as the used database. Specifying the used database is especially important because the default database name in the driverConfig is not compatible with Memgraph.

Run the application

Run the application using the following code:

node index.js

Interact with Memgraph

You are now ready to interact with Memgraph using GraphQL queries through localhost(127.0.0.1):4000.