NasaClient.java

/*
 * Copyright (C) 2017 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.recipes;

import java.io.IOException;
import java.io.InputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.security.GeneralSecurityException;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.NoSuchAlgorithmException;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;
import okhttp3.CipherSuite;
import okhttp3.ConnectionSpec;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okio.Buffer;

public final class NasaClient {
  private final OkHttpClient client;

  public NasaClient() throws GeneralSecurityException {
    // Configure cipher suites to demonstrate how to customize which cipher suites will be used for
    // an OkHttp request. In order to be selected a cipher suite must be included in both OkHttp's
    // connection spec and in the SSLSocket's enabled cipher suites array. Most applications should
    // not customize the cipher suites list.
    List<CipherSuite> customCipherSuites = Arrays.asList(
        CipherSuite.TLS_DHE_RSA_WITH_AES_128_GCM_SHA256);
    final ConnectionSpec spec = new ConnectionSpec.Builder(ConnectionSpec.MODERN_TLS)
        .cipherSuites(customCipherSuites.toArray(new CipherSuite[0]))
        .build();

    boolean useCustomTrustManager = true;
    X509TrustManager trustManager = useCustomTrustManager
        ? trustManagerForCertificates(trustedCertificatesInputStream())
        : defaultTrustManager();
    SSLSocketFactory sslSocketFactory = defaultSslSocketFactory(trustManager);
    SSLSocketFactory customSslSocketFactory = new DelegatingSSLSocketFactory(sslSocketFactory) {
      @Override protected SSLSocket configureSocket(SSLSocket socket) throws IOException {
        socket.setEnabledCipherSuites(javaNames(spec.cipherSuites()));
        return socket;
      }
    };

    client = new OkHttpClient.Builder()
        .connectionSpecs(Collections.singletonList(spec))
        .sslSocketFactory(customSslSocketFactory, trustManager)
        .build();
  }

  /**
   * Returns the VM's default SSL socket factory, using {@code trustManager} for trusted root
   * certificates.
   */
  private SSLSocketFactory defaultSslSocketFactory(X509TrustManager trustManager)
      throws NoSuchAlgorithmException, KeyManagementException {
    SSLContext sslContext = SSLContext.getInstance("TLS");
    sslContext.init(null, new TrustManager[] { trustManager }, null);

    return sslContext.getSocketFactory();
  }

  /** Returns a trust manager that trusts the VM's default certificate authorities. */
  private X509TrustManager defaultTrustManager() throws GeneralSecurityException {
    TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(
        TrustManagerFactory.getDefaultAlgorithm());
    trustManagerFactory.init((KeyStore) null);
    TrustManager[] trustManagers = trustManagerFactory.getTrustManagers();
    if (trustManagers.length != 1 || !(trustManagers[0] instanceof X509TrustManager)) {
      throw new IllegalStateException("Unexpected default trust managers:"
          + Arrays.toString(trustManagers));
    }
    return (X509TrustManager) trustManagers[0];
  }

  private String[] javaNames(List<CipherSuite> cipherSuites) {
    String[] result = new String[cipherSuites.size()];
    for (int i = 0; i < result.length; i++) {
      result[i] = cipherSuites.get(i).javaName();
    }
    return result;
  }


  /**
   * Returns a trust manager that trusts {@code certificates} and none other. HTTPS services whose
   * certificates have not been signed by these certificates will fail with a {@code
   * SSLHandshakeException}.
   *
   * <p>This can be used to replace the host platform's built-in trusted certificates with a custom
   * set. This is useful in development where certificate authority-trusted certificates aren't
   * available. Or in production, to avoid reliance on third-party certificate authorities.
   *
   * <p>See also {@link CertificatePinner}, which can limit trusted certificates while still using
   * the host platform's built-in trust store.
   *
   * <h3>Warning: Customizing Trusted Certificates is Dangerous!</h3>
   *
   * <p>Relying on your own trusted certificates limits your server team's ability to update their
   * TLS certificates. By installing a specific set of trusted certificates, you take on additional
   * operational complexity and limit your ability to migrate between certificate authorities. Do
   * not use custom trusted certificates in production without the blessing of your server's TLS
   * administrator.
   */
  private X509TrustManager trustManagerForCertificates(InputStream in)
      throws GeneralSecurityException {
    CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
    Collection<? extends Certificate> certificates = certificateFactory.generateCertificates(in);
    if (certificates.isEmpty()) {
      throw new IllegalArgumentException("expected non-empty set of trusted certificates");
    }

    // Put the certificates a key store.
    char[] password = "password".toCharArray(); // Any password will work.
    KeyStore keyStore = newEmptyKeyStore(password);
    int index = 0;
    for (Certificate certificate : certificates) {
      String certificateAlias = Integer.toString(index++);
      keyStore.setCertificateEntry(certificateAlias, certificate);
    }

    // Use it to build an X509 trust manager.
    KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(
        KeyManagerFactory.getDefaultAlgorithm());
    keyManagerFactory.init(keyStore, password);
    TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(
        TrustManagerFactory.getDefaultAlgorithm());
    trustManagerFactory.init(keyStore);
    TrustManager[] trustManagers = trustManagerFactory.getTrustManagers();
    if (trustManagers.length != 1 || !(trustManagers[0] instanceof X509TrustManager)) {
      throw new IllegalStateException("Unexpected default trust managers:"
          + Arrays.toString(trustManagers));
    }
    return (X509TrustManager) trustManagers[0];
  }

  private InputStream trustedCertificatesInputStream() {
    String idenTrustCommercialRootCa = ""
        + "-----BEGIN CERTIFICATE-----\n"
        + "MIIDSjCCAjKgAwIBAgIQRK+wgNajJ7qJMDmGLvhAazANBgkqhkiG9w0BAQUFADA/\n"
        + "MSQwIgYDVQQKExtEaWdpdGFsIFNpZ25hdHVyZSBUcnVzdCBDby4xFzAVBgNVBAMT\n"
        + "DkRTVCBSb290IENBIFgzMB4XDTAwMDkzMDIxMTIxOVoXDTIxMDkzMDE0MDExNVow\n"
        + "PzEkMCIGA1UEChMbRGlnaXRhbCBTaWduYXR1cmUgVHJ1c3QgQ28uMRcwFQYDVQQD\n"
        + "Ew5EU1QgUm9vdCBDQSBYMzCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEB\n"
        + "AN+v6ZdQCINXtMxiZfaQguzH0yxrMMpb7NnDfcdAwRgUi+DoM3ZJKuM/IUmTrE4O\n"
        + "rz5Iy2Xu/NMhD2XSKtkyj4zl93ewEnu1lcCJo6m67XMuegwGMoOifooUMM0RoOEq\n"
        + "OLl5CjH9UL2AZd+3UWODyOKIYepLYYHsUmu5ouJLGiifSKOeDNoJjj4XLh7dIN9b\n"
        + "xiqKqy69cK3FCxolkHRyxXtqqzTWMIn/5WgTe1QLyNau7Fqckh49ZLOMxt+/yUFw\n"
        + "7BZy1SbsOFU5Q9D8/RhcQPGX69Wam40dutolucbY38EVAjqr2m7xPi71XAicPNaD\n"
        + "aeQQmxkqtilX4+U9m5/wAl0CAwEAAaNCMEAwDwYDVR0TAQH/BAUwAwEB/zAOBgNV\n"
        + "HQ8BAf8EBAMCAQYwHQYDVR0OBBYEFMSnsaR7LHH62+FLkHX/xBVghYkQMA0GCSqG\n"
        + "SIb3DQEBBQUAA4IBAQCjGiybFwBcqR7uKGY3Or+Dxz9LwwmglSBd49lZRNI+DT69\n"
        + "ikugdB/OEIKcdBodfpga3csTS7MgROSR6cz8faXbauX+5v3gTt23ADq1cEmv8uXr\n"
        + "AvHRAosZy5Q6XkjEGB5YGV8eAlrwDPGxrancWYaLbumR9YbK+rlmM6pZW87ipxZz\n"
        + "R8srzJmwN0jP41ZL9c8PDHIyh8bwRLtTcm1D9SZImlJnt1ir/md2cXjbDaJWFBM5\n"
        + "JDGFoqgCWjBH4d1QB7wCCZAA62RjYJsWvIjJEubSfZGL+T0yjWW06XyxV3bqxbYo\n"
        + "Ob8VZRzI9neWagqNdwvYkQsEjgfbKbYK7p2CNTUQ\n"
        + "-----END CERTIFICATE-----\n";
    return new Buffer()
        .writeUtf8(idenTrustCommercialRootCa)
        .inputStream();
  }

  private KeyStore newEmptyKeyStore(char[] password) throws GeneralSecurityException {
    try {
      KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
      InputStream in = null; // By convention, 'null' creates an empty key store.
      keyStore.load(in, password);
      return keyStore;
    } catch (IOException e) {
      throw new AssertionError(e);
    }
  }

  /**
   * An SSL socket factory that forwards all calls to a delegate. Override {@link #configureSocket}
   * to customize a created socket before it is returned.
   */
  static class DelegatingSSLSocketFactory extends SSLSocketFactory {
    protected final SSLSocketFactory delegate;

    public DelegatingSSLSocketFactory(SSLSocketFactory delegate) {
      this.delegate = delegate;
    }

    @Override public String[] getDefaultCipherSuites() {
      return delegate.getDefaultCipherSuites();
    }

    @Override public String[] getSupportedCipherSuites() {
      return delegate.getSupportedCipherSuites();
    }

    @Override public Socket createSocket(
        Socket socket, String host, int port, boolean autoClose) throws IOException {
      return configureSocket((SSLSocket) delegate.createSocket(socket, host, port, autoClose));
    }

    @Override public Socket createSocket(String host, int port) throws IOException {
      return configureSocket((SSLSocket) delegate.createSocket(host, port));
    }

    @Override public Socket createSocket(
        String host, int port, InetAddress localHost, int localPort) throws IOException {
      return configureSocket((SSLSocket) delegate.createSocket(host, port, localHost, localPort));
    }

    @Override public Socket createSocket(InetAddress host, int port) throws IOException {
      return configureSocket((SSLSocket) delegate.createSocket(host, port));
    }

    @Override public Socket createSocket(
        InetAddress address, int port, InetAddress localAddress, int localPort) throws IOException {
      return configureSocket((SSLSocket) delegate.createSocket(
          address, port, localAddress, localPort));
    }

    protected SSLSocket configureSocket(SSLSocket socket) throws IOException {
      return socket;
    }
  }

  public void run() throws Exception {
    Request request = new Request.Builder()
        .url("https://apod.nasa.gov/apod/astropix.html")
        .build();

    try (Response response = client.newCall(request).execute()) {
      if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

      System.out.println(response.handshake().cipherSuite());
      System.out.println(response.body().string());
    }
  }

  public static void main(String... args) throws Exception {
    new NasaClient().run();
  }
}