memgraph/docs/user_technical/drivers.md

Bolt Drivers

Clients connect to Memgraph using the Bolt protocol. Bolt was designed for efficient communication with graph databases. Memgraph supports Version 1 of the protocol. Official Bolt protocol drivers are provided for multiple programming languages:

• Java
• Python
• Javascript
• C#

Python Driver Example

Neo4j officially supports Python for interacting with an openCypher and Bolt compliant database. For details consult the official documentation and the GitHub project. Following is a basic usage example:

from neo4j.v1 import GraphDatabase, basic_auth

# Initialize and configure the driver.
#   * provide the correct URL where Memgraph is reachable;
#   * use an empty user name and password, and
#   * disable encryption (not supported).
driver = GraphDatabase.driver("bolt://localhost:7687",
                              auth=basic_auth("", ""),
                              encrypted=False)

# Start a session in which queries are executed.
session = driver.session()

# Execute openCypher queries.
# After each query, call either `consume()` or `data()`
session.run('CREATE (alice:Person {name: "Alice", age: 22})').consume()

# Get all the vertices from the database (potentially multiple rows).
vertices = session.run('MATCH (n) RETURN n').data()
# Assuming we started with an empty database, we should have Alice
# as the only row in the results.
only_row = vertices.pop()
alice = only_row["n"]

# Print out what we retrieved.
print("Found a vertex with labels '{}', name '{}' and age {}".format(
  alice['name'], alice.labels, alice['age'])

# Remove all the data from the database.
session.run('MATCH (n) DETACH DELETE n').consume()

# Close the session and the driver.
session.close()
driver.close()

Java Driver Example

The details about Java driver can be found on GitHub.

The example below is equivalent to Python example. Major difference is that Config object has to be created before the driver construction. Encryption has to be disabled by calling withoutEncryption method against the Config builder.

import org.neo4j.driver.v1.*;
import org.neo4j.driver.v1.types.*;
import static org.neo4j.driver.v1.Values.parameters;
import java.util.*;

public class JavaQuickStart {
    public static void main(String[] args) {
        // Initialize driver.
        Config config = Config.build().withoutEncryption().toConfig();
        Driver driver = GraphDatabase.driver("bolt://localhost:7687",
                                             AuthTokens.basic("",""),
                                             config);
        // Execute basic queries.
        try (Session session = driver.session()) {
            StatementResult rs1 = session.run("MATCH (n) DETACH DELETE n");
            StatementResult rs2 = session.run(
                "CREATE (alice: Person {name: 'Alice', age: 22})");
            StatementResult rs3 = session.run( "MATCH (n) RETURN n");
            List<Record> records = rs3.list();
            Record record = records.get(0);
            Node node = record.get("n").asNode();
            System.out.println(node.get("name").asString());
        } catch (Exception e) {
            System.out.println(e);
            System.exit(1);
        }
        // Cleanup.
        driver.close();
    }
}

Javascript Driver Example

The details about Javascript driver can be found on GitHub.

The Javascript example below is equivalent to Python and Java examples. SSL can be disabled by passing {encrypted: 'ENCRYPTION_OFF'} during the driver construction.

Here is an example related to Node.js. Memgraph doesn't have integrated support for WebSocket which is required during the execution in any web browser. If you want to run openCypher queries from a web browser, websockify has to be up and running. Requests from web browsers are wrapped into WebSocket messages, and a proxy is needed to handle the overhead. The proxy has to be configured to point out to Memgraph's Bolt port and web browser driver has to send requests to the proxy port.

var neo4j = require('neo4j-driver').v1;
var driver = neo4j.driver("bolt://localhost:7687",
                          neo4j.auth.basic("neo4j", "1234"),
                          {encrypted: 'ENCRYPTION_OFF'});
var session = driver.session();

function die() {
  session.close();
  driver.close();
}

function run_query(query, callback) {
  var run = session.run(query, {});
  run.then(callback).catch(function (error) {
    console.log(error);
    die();
  });
}

run_query("MATCH (n) DETACH DELETE n", function (result) {
  console.log("Database cleared.");
  run_query("CREATE (alice: Person {name: 'Alice', age: 22})", function (result) {
    console.log("Record created.");
    run_query("MATCH (n) RETURN n", function (result) {
      console.log("Record matched.");
      var alice = result.records[0].get("n");
      console.log(alice.labels[0]);
      console.log(alice.properties["name"]);
      session.close();
      driver.close();
    });
  });
});

C# Driver Example

The C# driver is hosted on GitHub. The example below performs the same work as all of the previous examples. Encryption is disabled by setting EncryptionLevel.NONE on the Config.

using System;
using System.Linq;
using Neo4j.Driver.V1;

public class Basic {
  public static void Main(string[] args) {
    // Initialize the driver.
    var config = Config.DefaultConfig;
    config.EncryptionLevel = EncryptionLevel.None;
    using(var driver = GraphDatabase.Driver("bolt://localhost:7687", AuthTokens.None, config))
      using(var session = driver.Session())
      {
        // Run basic queries.
        session.Run("MATCH (n) DETACH DELETE n").Consume();
        session.Run("CREATE (alice:Person {name: \"Alice\", age: 22})").Consume();
        var result = session.Run("MATCH (n) RETURN n").First();
        var alice = (INode) result["n"];
        Console.WriteLine(alice["name"]);
        Console.WriteLine(string.Join(", ", alice.Labels));
        Console.WriteLine(alice["age"]);
      }
    Console.WriteLine("All ok!");
  }
}

Limitations

Memgraph is currently in early stage, and has a number of limitations we plan to remove in future versions.

Multiple Users & Authorization

Memgraph is currently single-user only. There is no way to control user privileges. The default user has read and write privileges over the whole database.

Secure Sockets Layer (SSL)

Secure connections are not supported. For this reason each client driver needs to be configured not to use encryption. Consult driver-specific guides for details.