Menggunakan protokol Bolt untuk membuat kueri OpenCypher ke Neptunus

Bolt adalah protokol klien/server berorientasi pernyataan yang awalnya dikembangkan oleh Neo4j dan dilisensikan di bawah lisensi Creative Commons 3.0 Attribution-. ShareAlike Ini didorong oleh klien, artinya klien selalu memulai pertukaran pesan.

Untuk terhubung ke Neptunus menggunakan driver Bolt Neo4j, cukup ganti URL dan nomor Port dengan titik akhir cluster Anda menggunakan skema URI. bolt Jika Anda memiliki satu instance Neptunus yang berjalan, gunakan endpoint read_write. Jika beberapa instance berjalan, maka dua driver direkomendasikan, satu untuk penulis dan satu lagi untuk semua replika baca. Jika Anda hanya memiliki dua titik akhir default, driver read_write dan read_only sudah cukup, tetapi jika Anda memiliki titik akhir khusus juga, pertimbangkan untuk membuat instance driver untuk masing-masing titik akhir.

catatan

Meskipun spesifikasi Bolt menyatakan bahwa Bolt dapat terhubung menggunakan TCP atau, WebSockets Neptunus hanya mendukung koneksi TCP untuk Bolt.

Neptunus memungkinkan hingga 1000 koneksi Bolt bersamaan.

Untuk contoh kueri OpenCypher dalam berbagai bahasa yang menggunakan driver Bolt, lihat dokumentasi Neo4j Drivers & Language Guides.

penting

Driver Neo4j Bolt untuk Python, .NET JavaScript, dan Golang awalnya tidak mendukung pembaruan otomatis token otentikasi Signature v4. AWS Ini berarti bahwa setelah tanda tangan kedaluwarsa (seringkali dalam 5 menit), pengemudi gagal mengautentikasi, dan permintaan berikutnya gagal. Contoh Python, .NET JavaScript, dan Go di bawah ini semuanya terpengaruh oleh masalah ini.

Lihat masalah driver Python Neo4j #834, masalah Neo4j .NET #664, masalah driverNeo4j #993, dan masalah JavaScriptdriver Neo4j GoLang #429 untuk informasi lebih lanjut.

Pada driver versi 5.8.0, API otentikasi ulang pratinjau baru dirilis untuk driver Go (lihat v5.8.0 - Umpan balik diinginkan pada otentikasi ulang).

Menggunakan Bolt dengan Java untuk terhubung ke Neptunus

Anda dapat mengunduh driver untuk versi apa pun yang ingin Anda gunakan dari repositori Maven MVN, atau dapat menambahkan ketergantungan ini ke proyek Anda:

<dependency>
  <groupId>org.neo4j.driver</groupId>
  <artifactId>neo4j-java-driver</artifactId>
  <version>4.3.3</version>
</dependency>

Kemudian, untuk terhubung ke Neptunus di Jawa menggunakan salah satu driver Bolt ini, buat instance driver untuk instance primer/writer di cluster Anda menggunakan kode seperti berikut:

import org.neo4j.driver.Driver;
import org.neo4j.driver.GraphDatabase;

final Driver driver =
  GraphDatabase.driver("bolt://(your cluster endpoint URL):(your cluster port)",
    AuthTokens.none(),
    Config.builder().withEncryption()
                    .withTrustStrategy(TrustStrategy.trustSystemCertificates())
                    .build());

Jika Anda memiliki satu atau lebih replika pembaca, Anda juga dapat membuat instance driver untuk mereka menggunakan kode seperti ini:

final Driver read_only_driver =              // (without connection timeout)
  GraphDatabase.driver("bolt://(your cluster endpoint URL):(your cluster port)",
      Config.builder().withEncryption()
                      .withTrustStrategy(TrustStrategy.trustSystemCertificates())
                      .build());

Atau, dengan batas waktu:

final Driver read_only_timeout_driver =      // (with connection timeout)
  GraphDatabase.driver("bolt://(your cluster endpoint URL):(your cluster port)",
    Config.builder().withConnectionTimeout(30, TimeUnit.SECONDS)
                    .withEncryption()
                    .withTrustStrategy(TrustStrategy.trustSystemCertificates())
                    .build());

Jika Anda memiliki titik akhir khusus, mungkin juga bermanfaat untuk membuat instance driver untuk masing-masing titik.

Contoh kueri Python OpenCypher menggunakan Bolt

Berikut ini cara membuat kueri OpenCypher dengan Python menggunakan Bolt:

python -m pip install neo4j

from neo4j import GraphDatabase
uri = "bolt://(your cluster endpoint URL):(your cluster port)"
driver = GraphDatabase.driver(uri, auth=("username", "password"), encrypted=True)

Perhatikan bahwa auth parameter diabaikan.

Contoh kueri.NET OpenCypher menggunakan Bolt

Untuk membuat kueri OpenCypher di.NET menggunakan Bolt, langkah pertama adalah menginstal driver Neo4j menggunakan. NuHet Untuk melakukan panggilan sinkron, gunakan .Simple versi, seperti ini:

Install-Package Neo4j.Driver.Simple-4.3.0

using Neo4j.Driver;

namespace hello
{
  // This example creates a node and reads a node in a Neptune
  // Cluster where IAM Authentication is not enabled.
  public class HelloWorldExample : IDisposable
  {
    private bool _disposed = false;
    private readonly IDriver _driver;
    private static string url = "bolt://(your cluster endpoint URL):(your cluster port)";
    private static string createNodeQuery = "CREATE (a:Greeting) SET a.message = 'HelloWorldExample'";
    private static string readNodeQuery = "MATCH(n:Greeting) RETURN n.message";

    ~HelloWorldExample() => Dispose(false);

    public HelloWorldExample(string uri)
    {
      _driver = GraphDatabase.Driver(uri, AuthTokens.None, o => o.WithEncryptionLevel(EncryptionLevel.Encrypted));
    }

    public void createNode()
    {
      // Open a session
      using (var session = _driver.Session())
      {
         // Run the query in a write transaction
        var greeting = session.WriteTransaction(tx =>
        {
          var result = tx.Run(createNodeQuery);
          // Consume the result
          return result.Consume();
        });

        // The output will look like this:
        //   ResultSummary{Query=`CREATE (a:Greeting) SET a.message = 'HelloWorldExample".....
        Console.WriteLine(greeting);
      }
    }

    public void retrieveNode()
    {
      // Open a session
      using (var session = _driver.Session())
      {
        // Run the query in a read transaction
        var greeting = session.ReadTransaction(tx =>
        {
          var result = tx.Run(readNodeQuery);
          // Consume the result. Read the single node
          // created in a previous step.
          return result.Single()[0].As<string>();
        });
        // The output will look like this:
        //   HelloWorldExample
        Console.WriteLine(greeting);
      }
    }

    public void Dispose()
    {
      Dispose(true);
      GC.SuppressFinalize(this);
    }

    protected virtual void Dispose(bool disposing)
    {
      if (_disposed)
        return;
      if (disposing)
      {
        _driver?.Dispose();
      }
      _disposed = true;
    }

    public static void Main()
    {
      using (var apiCaller = new HelloWorldExample(url))
      {
        apiCaller.createNode();
        apiCaller.retrieveNode();
      }
    }
  }
}

Contoh kueri Java OpenCypher menggunakan Bolt dengan otentikasi IAM

Kode Java di bawah ini menunjukkan cara membuat query OpenCypher di Java menggunakan Bolt dengan otentikasi IAM. JavaDoc Komentar tersebut menjelaskan penggunaannya. Setelah instance driver tersedia, Anda dapat menggunakannya untuk membuat beberapa permintaan yang diautentikasi.

package software.amazon.neptune.bolt;

import com.amazonaws.DefaultRequest;
import com.amazonaws.Request;
import com.amazonaws.auth.AWS4Signer;
import com.amazonaws.auth.AWSCredentialsProvider;
import com.amazonaws.http.HttpMethodName;
import com.google.gson.Gson;
import lombok.Builder;
import lombok.Getter;
import lombok.NonNull;
import org.neo4j.driver.Value;
import org.neo4j.driver.Values;
import org.neo4j.driver.internal.security.InternalAuthToken;
import org.neo4j.driver.internal.value.StringValue;

import java.net.URI;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import static com.amazonaws.auth.internal.SignerConstants.AUTHORIZATION;
import static com.amazonaws.auth.internal.SignerConstants.HOST;
import static com.amazonaws.auth.internal.SignerConstants.X_AMZ_DATE;
import static com.amazonaws.auth.internal.SignerConstants.X_AMZ_SECURITY_TOKEN;

/**
 * Use this class instead of `AuthTokens.basic` when working with an IAM
 * auth-enabled server. It works the same as `AuthTokens.basic` when using
 * static credentials, and avoids making requests with an expired signature
 * when using temporary credentials. Internally, it generates a new signature
 * on every invocation (this may change in a future implementation).
 *
 * Note that authentication happens only the first time for a pooled connection.
 *
 * Typical usage:
 *
 * NeptuneAuthToken authToken = NeptuneAuthToken.builder()
 *     .credentialsProvider(credentialsProvider)
 *     .region("aws region")
 *     .url("cluster endpoint url")
 *     .build();
 *
 * Driver driver = GraphDatabase.driver(
 *     authToken.getUrl(),
 *     authToken,
 *     config
 * );
 */

public class NeptuneAuthToken extends InternalAuthToken {
  private static final String SCHEME = "basic";
  private static final String REALM = "realm";
  private static final String SERVICE_NAME = "neptune-db";
  private static final String HTTP_METHOD_HDR = "HttpMethod";
  private static final String DUMMY_USERNAME = "username";
  @NonNull
  private final String region;
  @NonNull
  @Getter
  private final String url;
  @NonNull
  private final AWSCredentialsProvider credentialsProvider;
  private final Gson gson = new Gson();

  @Builder
  private NeptuneAuthToken(
      @NonNull final String region,
      @NonNull final String url,
      @NonNull final AWSCredentialsProvider credentialsProvider
  ) {
      // The superclass caches the result of toMap(), which we don't want
      super(Collections.emptyMap());
      this.region = region;
      this.url = url;
      this.credentialsProvider = credentialsProvider;
  }

  @Override
  public Map<String, Value> toMap() {
    final Map<String, Value> map = new HashMap<>();
    map.put(SCHEME_KEY, Values.value(SCHEME));
    map.put(PRINCIPAL_KEY, Values.value(DUMMY_USERNAME));
    map.put(CREDENTIALS_KEY, new StringValue(getSignedHeader()));
    map.put(REALM_KEY, Values.value(REALM));

    return map;
  }

  private String getSignedHeader() {
    final Request<Void> request = new DefaultRequest<>(SERVICE_NAME);
    request.setHttpMethod(HttpMethodName.GET);
    request.setEndpoint(URI.create(url));
    // Comment out the following line if you're using an engine version older than 1.2.0.0
    request.setResourcePath("/opencypher");

    final AWS4Signer signer = new AWS4Signer();
    signer.setRegionName(region);
    signer.setServiceName(request.getServiceName());
    signer.sign(request, credentialsProvider.getCredentials());

    return getAuthInfoJson(request);
  }

  private String getAuthInfoJson(final Request<Void> request) {
    final Map<String, Object> obj = new HashMap<>();
    obj.put(AUTHORIZATION, request.getHeaders().get(AUTHORIZATION));
    obj.put(HTTP_METHOD_HDR, request.getHttpMethod());
    obj.put(X_AMZ_DATE, request.getHeaders().get(X_AMZ_DATE));
    obj.put(HOST, request.getHeaders().get(HOST));
    obj.put(X_AMZ_SECURITY_TOKEN, request.getHeaders().get(X_AMZ_SECURITY_TOKEN));

    return gson.toJson(obj);
  }
}

Contoh kueri OpenCypher Python menggunakan Bolt dengan otentikasi IAM

Kelas Python di bawah ini memungkinkan Anda membuat kueri OpenCypher dengan Python menggunakan Bolt dengan otentikasi IAM:

import json

from neo4j import Auth
from botocore.awsrequest import AWSRequest
from botocore.credentials import Credentials
from botocore.auth import (
  SigV4Auth,
  _host_from_url,
)

SCHEME = "basic"
REALM = "realm"
SERVICE_NAME = "neptune-db"
DUMMY_USERNAME = "username"
HTTP_METHOD_HDR = "HttpMethod"
HTTP_METHOD = "GET"
AUTHORIZATION = "Authorization"
X_AMZ_DATE = "X-Amz-Date"
X_AMZ_SECURITY_TOKEN = "X-Amz-Security-Token"
HOST = "Host"


class NeptuneAuthToken(Auth):
  def __init__(
    self,
    credentials: Credentials,
    region: str,
    url: str,
    **parameters
  ):
    # Do NOT add "/opencypher" in the line below if you're using an engine version older than 1.2.0.0
    request = AWSRequest(method=HTTP_METHOD, url=url + "/opencypher")
    request.headers.add_header("Host", _host_from_url(request.url))
    sigv4 = SigV4Auth(credentials, SERVICE_NAME, region)
    sigv4.add_auth(request)

    auth_obj = {
      hdr: request.headers[hdr]
      for hdr in [AUTHORIZATION, X_AMZ_DATE, X_AMZ_SECURITY_TOKEN, HOST]
    }
    auth_obj[HTTP_METHOD_HDR] = request.method
    creds: str = json.dumps(auth_obj)
    super().__init__(SCHEME, DUMMY_USERNAME, creds, REALM, **parameters)

Anda menggunakan kelas ini untuk membuat driver sebagai berikut:

  authToken = NeptuneAuthToken(creds, REGION, URL)
  driver = GraphDatabase.driver(URL, auth=authToken, encrypted=True)

Contoh Node.js menggunakan otentikasi IAM dan Bolt

Kode Node.js di bawah ini menggunakan AWS sintaks SDK untuk JavaScript versi 3 dan ES6 untuk membuat driver yang mengautentikasi permintaan:

import neo4j from "neo4j-driver";
import { HttpRequest }  from "@aws-sdk/protocol-http";
import { defaultProvider } from "@aws-sdk/credential-provider-node";
import { SignatureV4 } from "@aws-sdk/signature-v4";
import crypto from "@aws-crypto/sha256-js";
const { Sha256 } = crypto;
import assert from "node:assert";

const region = "us-west-2";
const serviceName = "neptune-db";
const host = "(your cluster endpoint URL)";
const port = 8182;
const protocol = "bolt";
const hostPort = host + ":" + port;
const url = protocol + "://" + hostPort;
const createQuery = "CREATE (n:Greeting {message: 'Hello'}) RETURN ID(n)";
const readQuery = "MATCH(n:Greeting) WHERE ID(n) = $id RETURN n.message";

async function signedHeader() {
  const req = new HttpRequest({
    method: "GET",
    protocol: protocol,
    hostname: host,
    port: port,
    // Comment out the following line if you're using an engine version older than 1.2.0.0
    path: "/opencypher",
    headers: {
      host: hostPort
    }
  });

  const signer = new SignatureV4({
    credentials: defaultProvider(),
    region: region,
    service: serviceName,
    sha256: Sha256
  });

  return signer.sign(req, { unsignableHeaders: new Set(["x-amz-content-sha256"]) })
    .then((signedRequest) => {
      const authInfo = {
        "Authorization": signedRequest.headers["authorization"],
        "HttpMethod": signedRequest.method,
        "X-Amz-Date": signedRequest.headers["x-amz-date"],
        "Host": signedRequest.headers["host"],
        "X-Amz-Security-Token": signedRequest.headers["x-amz-security-token"]
      };
      return JSON.stringify(authInfo);
    });
}

async function createDriver() {
  let authToken = { scheme: "basic", realm: "realm", principal: "username", credentials: await signedHeader() };

  return neo4j.driver(url, authToken, {
      encrypted: "ENCRYPTION_ON",
      trust: "TRUST_SYSTEM_CA_SIGNED_CERTIFICATES",
      maxConnectionPoolSize: 1,
      // logging: neo4j.logging.console("debug")
    }
  );
}

function unmanagedTxn(driver) {
  const session = driver.session();
  const tx = session.beginTransaction();
  tx.run(createQuery)
  .then((res) => {
    const id = res.records[0].get(0);
    return tx.run(readQuery, { id: id });
  })
  .then((res) => {
    // All good, the transaction will be committed
    const msg = res.records[0].get("n.message");
    assert.equal(msg, "Hello");
  })
  .catch(err => {
    // The transaction will be rolled back, now handle the error.
    console.log(err);
  })
  .then(() => session.close());
}

createDriver()
.then((driver) => {
  unmanagedTxn(driver);
  driver.close();
})
.catch((err) => {
  console.log(err);
});

Contoh kueri.NET OpenCypher menggunakan Bolt dengan otentikasi IAM

Untuk mengaktifkan otentikasi IAM di .NET, Anda perlu menandatangani permintaan saat membuat koneksi. Contoh di bawah ini menunjukkan cara membuat NeptuneAuthToken helper untuk menghasilkan token otentikasi:

using Amazon.Runtime;
using Amazon.Util;
using Neo4j.Driver;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json;
using System.Web;

namespace Hello
{
  /*
   * Use this class instead of `AuthTokens.None` when working with an IAM-auth-enabled server.
   *
   * Note that authentication happens only the first time for a pooled connection.
   *
   * Typical usage:
   *
   * var authToken = new NeptuneAuthToken(AccessKey, SecretKey, Region).GetAuthToken(Host);
   * _driver = GraphDatabase.Driver(Url, authToken, o => o.WithEncryptionLevel(EncryptionLevel.Encrypted));
   */

  public class NeptuneAuthToken
  {
    private const string ServiceName = "neptune-db";
    private const string Scheme = "basic";
    private const string Realm = "realm";
    private const string DummyUserName = "username";
    private const string Algorithm = "AWS4-HMAC-SHA256";
    private const string AWSRequest = "aws4_request";

    private readonly string _accessKey;
    private readonly string _secretKey;
    private readonly string _region;

    private readonly string _emptyPayloadHash;

    private readonly SHA256 _sha256;


    public NeptuneAuthToken(string awsKey = null, string secretKey = null, string region = null)
    {
      var awsCredentials = awsKey == null || secretKey == null
        ? FallbackCredentialsFactory.GetCredentials().GetCredentials()
        : null;

      _accessKey = awsKey ?? awsCredentials.AccessKey;
      _secretKey = secretKey ?? awsCredentials.SecretKey;
      _region = region ?? FallbackRegionFactory.GetRegionEndpoint().SystemName; //ex: us-east-1

      _sha256 = SHA256.Create();
      _emptyPayloadHash = Hash(Array.Empty<byte>());
    }

    public IAuthToken GetAuthToken(string url)
    {
      return AuthTokens.Custom(DummyUserName, GetCredentials(url), Realm, Scheme);
    }

    /******************** AWS SIGNING FUNCTIONS *********************/
    private string Hash(byte[] bytesToHash)
    {
      return ToHexString(_sha256.ComputeHash(bytesToHash));
    }

    private static byte[] HmacSHA256(byte[] key, string data)
    {
      return new HMACSHA256(key).ComputeHash(Encoding.UTF8.GetBytes(data));
    }

    private byte[] GetSignatureKey(string dateStamp)
    {
      var kSecret = Encoding.UTF8.GetBytes($"AWS4{_secretKey}");
      var kDate = HmacSHA256(kSecret, dateStamp);
      var kRegion = HmacSHA256(kDate, _region);
      var kService = HmacSHA256(kRegion, ServiceName);
      return HmacSHA256(kService, AWSRequest);
    }

    private static string ToHexString(byte[] array)
    {
      return Convert.ToHexString(array).ToLowerInvariant();
    }

    private string GetCredentials(string url)
    {
      var request = new HttpRequestMessage
      {
        Method = HttpMethod.Get,
        RequestUri = new Uri($"https://{url}/opencypher")
      };

      var signedrequest = Sign(request);

      var headers = new Dictionary<string, object>
      {
        [HeaderKeys.AuthorizationHeader] = signedrequest.Headers.GetValues(HeaderKeys.AuthorizationHeader).FirstOrDefault(),
        ["HttpMethod"] = HttpMethod.Get.ToString(),
        [HeaderKeys.XAmzDateHeader] = signedrequest.Headers.GetValues(HeaderKeys.XAmzDateHeader).FirstOrDefault(),
        // Host should be capitalized, not like in Amazon.Util.HeaderKeys.HostHeader
        ["Host"] = signedrequest.Headers.GetValues(HeaderKeys.HostHeader).FirstOrDefault(),
      };

      return JsonSerializer.Serialize(headers);
    }

    private HttpRequestMessage Sign(HttpRequestMessage request)
    {
      var now = DateTimeOffset.UtcNow;
      var amzdate = now.ToString("yyyyMMddTHHmmssZ");
      var datestamp = now.ToString("yyyyMMdd");

      if (request.Headers.Host == null)
      {
        request.Headers.Host = $"{request.RequestUri.Host}:{request.RequestUri.Port}";
      }

      request.Headers.Add(HeaderKeys.XAmzDateHeader, amzdate);

      var canonicalQueryParams = GetCanonicalQueryParams(request);

      var canonicalRequest = new StringBuilder();
      canonicalRequest.Append(request.Method + "\n");
      canonicalRequest.Append(request.RequestUri.AbsolutePath + "\n");
      canonicalRequest.Append(canonicalQueryParams + "\n");

      var signedHeadersList = new List<string>();
      foreach (var header in request.Headers.OrderBy(a => a.Key.ToLowerInvariant()))
      {
        canonicalRequest.Append(header.Key.ToLowerInvariant());
        canonicalRequest.Append(':');
        canonicalRequest.Append(string.Join(",", header.Value.Select(s => s.Trim())));
        canonicalRequest.Append('\n');
        signedHeadersList.Add(header.Key.ToLowerInvariant());
      }
      canonicalRequest.Append('\n');

      var signedHeaders = string.Join(";", signedHeadersList);
      canonicalRequest.Append(signedHeaders + "\n");
      canonicalRequest.Append(_emptyPayloadHash);

      var credentialScope = $"{datestamp}/{_region}/{ServiceName}/{AWSRequest}";
      var stringToSign = $"{Algorithm}\n{amzdate}\n{credentialScope}\n"
        + Hash(Encoding.UTF8.GetBytes(canonicalRequest.ToString()));

      var signing_key = GetSignatureKey(datestamp);
      var signature = ToHexString(HmacSHA256(signing_key, stringToSign));

      request.Headers.TryAddWithoutValidation(HeaderKeys.AuthorizationHeader,
        $"{Algorithm} Credential={_accessKey}/{credentialScope}, SignedHeaders={signedHeaders}, Signature={signature}");

      return request;
    }

    private static string GetCanonicalQueryParams(HttpRequestMessage request)
    {
      var querystring = HttpUtility.ParseQueryString(request.RequestUri.Query);

      // Query params must be escaped in upper case (i.e. "%2C", not "%2c").
      var queryParams = querystring.AllKeys.OrderBy(a => a)
        .Select(key => $"{key}={Uri.EscapeDataString(querystring[key])}");
      return string.Join("&", queryParams);
    }
  }
}

Berikut adalah cara membuat query OpenCypher di.NET menggunakan Bolt dengan otentikasi IAM. Contoh di bawah ini menggunakan NeptuneAuthToken helper:

using Neo4j.Driver;

namespace Hello
{
  public class HelloWorldExample
  {
    private const string Host = "(your hostname):8182";
    private const string Url = $"bolt://{Host}";
    private const string CreateNodeQuery = "CREATE (a:Greeting) SET a.message = 'HelloWorldExample'";
    private const string ReadNodeQuery = "MATCH(n:Greeting) RETURN n.message";

    private const string AccessKey = "(your access key)";
    private const string SecretKey = "(your secret key)";
    private const string Region = "(your AWS region)"; // e.g. "us-west-2"

    private readonly IDriver _driver;

    public HelloWorldExample()
    {
      var authToken = new NeptuneAuthToken(AccessKey, SecretKey, Region).GetAuthToken(Host);

      // Note that when the connection is reinitialized after max connection lifetime
      // has been reached, the signature token could have already been expired (usually 5 min)
      // You can face exceptions like:
      //   `Unexpected server exception 'Signature expired: XXXX is now earlier than YYYY (ZZZZ - 5 min.)`
      _driver = GraphDatabase.Driver(Url, authToken, o =>
                o.WithMaxConnectionLifetime(TimeSpan.FromMinutes(60)).WithEncryptionLevel(EncryptionLevel.Encrypted));
    }

    public async Task CreateNode()
    {
      // Open a session
      using (var session = _driver.AsyncSession())
      {
        // Run the query in a write transaction
        var greeting = await session.WriteTransactionAsync(async tx =>
        {
          var result = await tx.RunAsync(CreateNodeQuery);
          // Consume the result
          return await result.ConsumeAsync();
        });

        // The output will look like this:
        //   ResultSummary{Query=`CREATE (a:Greeting) SET a.message = 'HelloWorldExample".....
        Console.WriteLine(greeting.Query);
      }
    }

    public async Task RetrieveNode()
    {
      // Open a session
      using (var session = _driver.AsyncSession())
      {
        // Run the query in a read transaction
        var greeting = await session.ReadTransactionAsync(async tx =>
        {
          var result = await tx.RunAsync(ReadNodeQuery);
          var records = await result.ToListAsync();

          // Consume the result. Read the single node
          // created in a previous step.
          return records[0].Values.First().Value;
        });
        // The output will look like this:
        //   HelloWorldExample
        Console.WriteLine(greeting);
      }
    }
  }
}

Contoh ini dapat diluncurkan dengan menjalankan kode di bawah ini pada .NET 6 atau .NET 7 dengan paket-paket berikut:

• Neo4j.Driver=4.3.0

• AWSSDK.Core=3.7.102.1

namespace Hello
{
  class Program
  {
    static async Task Main()
    {
      var apiCaller = new HelloWorldExample();

      await apiCaller.CreateNode();
      await apiCaller.RetrieveNode();
    }
  }
}

Contoh kueri Golang OpenCypher menggunakan Bolt dengan otentikasi IAM

Paket Golang di bawah ini menunjukkan cara membuat kueri OpenCypher dalam bahasa Go menggunakan Bolt dengan otentikasi IAM:

package main

import (
  "context"
  "encoding/json"
  "fmt"
  "github.com/aws/aws-sdk-go/aws/credentials"
  "github.com/aws/aws-sdk-go/aws/signer/v4"
  "github.com/neo4j/neo4j-go-driver/v5/neo4j"
  "log"
  "net/http"
  "os"
  "time"
)

const (
  ServiceName   = "neptune-db"
  DummyUsername = "username"
)

// Find node by id using Go driver
func findNode(ctx context.Context, region string, hostAndPort string, nodeId string) (string, error) {
  req, err := http.NewRequest(http.MethodGet, "https://"+hostAndPort+"/opencypher", nil)

  if err != nil {
    return "", fmt.Errorf("error creating request, %v", err)
  }

  // credentials must have been exported as environment variables
  signer := v4.NewSigner(credentials.NewEnvCredentials())
  _, err = signer.Sign(req, nil, ServiceName, region, time.Now())

  if err != nil {
    return "", fmt.Errorf("error signing request: %v", err)
  }

  hdrs := []string{"Authorization", "X-Amz-Date", "X-Amz-Security-Token"}
  hdrMap := make(map[string]string)
  for _, h := range hdrs {
    hdrMap[h] = req.Header.Get(h)
  }

  hdrMap["Host"] = req.Host
  hdrMap["HttpMethod"] = req.Method

  password, err := json.Marshal(hdrMap)
  if err != nil {
    return "", fmt.Errorf("error creating JSON, %v", err)
  }
  authToken := neo4j.BasicAuth(DummyUsername, string(password), "")
  // +s enables encryption with a full certificate check
  // Use +ssc to disable client side TLS verification
  driver, err := neo4j.NewDriverWithContext("bolt+s://"+hostAndPort+"/opencypher", authToken)
  if err != nil {
    return "", fmt.Errorf("error creating driver, %v", err)
  }

  defer driver.Close(ctx)

  if err := driver.VerifyConnectivity(ctx); err != nil {
    log.Fatalf("failed to verify connection, %v", err)
  }

  config := neo4j.SessionConfig{}

  session := driver.NewSession(ctx, config)
  defer session.Close(ctx)

  result, err := session.Run(
    ctx,
    fmt.Sprintf("MATCH (n) WHERE ID(n) = '%s' RETURN n", nodeId),
    map[string]any{},
  )
  if err != nil {
    return "", fmt.Errorf("error running query, %v", err)
  }

  if !result.Next(ctx) {
    return "", fmt.Errorf("node not found")
  }

  n, found := result.Record().Get("n")
  if !found {
    return "", fmt.Errorf("node not found")
  }

  return fmt.Sprintf("+%v\n", n), nil
}

func main() {
  if len(os.Args) < 3 {
    log.Fatal("Usage: go main.go (region) (host and port)")
  }
  region := os.Args[1]
  hostAndPort := os.Args[2]
  ctx := context.Background()

  res, err := findNode(ctx, region, hostAndPort, "72c2e8c1-7d5f-5f30-10ca-9d2bb8c4afbc")
  if err != nil {
    log.Fatal(err)
  }
  fmt.Println(res)
}

Perilaku koneksi baut di Neptunus

Berikut adalah beberapa hal yang perlu diingat tentang koneksi Neptunus Bolt:

• Karena koneksi Bolt dibuat pada layer TCP, Anda tidak dapat menggunakan Application Load Balancer di depannya, seperti yang Anda bisa dengan endpoint HTTP.

• Port yang digunakan Neptunus untuk koneksi Bolt adalah port cluster DB Anda.

• Berdasarkan pembukaan Bolt yang diteruskan ke sana, server Neptunus memilih versi Bolt tertinggi yang sesuai (1, 2, 3, atau 4.0).

• Jumlah maksimum koneksi ke server Neptunus yang dapat dibuka klien kapan saja adalah 1.000.

• Jika klien tidak menutup koneksi setelah kueri, koneksi itu dapat digunakan untuk menjalankan kueri berikutnya.

• Namun, jika koneksi menganggur selama 20 menit, server menutupnya secara otomatis.

• Jika autentikasi IAM tidak diaktifkan, Anda dapat menggunakan AuthTokens.none() daripada memasok nama pengguna dan kata sandi dummy. Misalnya, di Jawa:

  GraphDatabase.driver("bolt://(your cluster endpoint URL):(your cluster port)", AuthTokens.none(),
      Config.builder().withEncryption().withTrustStrategy(TrustStrategy.trustSystemCertificates()).build());

• Ketika autentikasi IAM diaktifkan, koneksi Bolt selalu terputus beberapa menit lebih dari 10 hari setelah dibuat jika belum ditutup karena alasan lain.

• Jika klien mengirim kueri untuk dieksekusi melalui koneksi tanpa menghabiskan hasil kueri sebelumnya, kueri baru akan dibuang. Untuk membuang hasil sebelumnya, klien harus mengirim pesan reset melalui koneksi.

• Hanya satu transaksi pada satu waktu yang dapat dibuat pada koneksi tertentu.

• Jika pengecualian terjadi selama transaksi, server Neptunus memutar kembali transaksi dan menutup koneksi. Dalam hal ini, driver membuat koneksi baru untuk kueri berikutnya.

• Ketahuilah bahwa sesi tidak aman untuk utas. Beberapa operasi paralel harus menggunakan beberapa sesi terpisah.