GsonSupplier.java

/*
 * Copyright 2022 The Sigstore Authors.
 *
 * 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 dev.sigstore.json;

import com.google.gson.*;
import dev.sigstore.dsse.GsonAdaptersInTotoPayload;
import dev.sigstore.rekor.client.GsonAdaptersRekorEntry;
import dev.sigstore.rekor.client.GsonAdaptersRekorEntryBody;
import dev.sigstore.tuf.model.*;
import java.time.LocalDateTime;
import java.time.ZonedDateTime;
import java.util.function.Supplier;

/**
 * Supplies a Gson with custom byte to base64 serialization, and no html escaping. This instance of
 * GSON is NOT html/url safe, but makes more sense if you want to do things for the serialization of
 * requests between sigstore and this client -- and should probably be used for any api call to
 * sigstore that expects JSON.
 */
public enum GsonSupplier implements Supplier<Gson> {
  GSON;

  @SuppressWarnings("ImmutableEnumChecker")
  private final Gson gson =
      new GsonBuilder()
          .registerTypeAdapter(byte[].class, new GsonByteArrayAdapter())
          .registerTypeAdapter(
              LocalDateTime.class,
              (JsonDeserializer<LocalDateTime>)
                  (json, type, jsonDeserializationContext) ->
                      ZonedDateTime.parse(json.getAsJsonPrimitive().getAsString())
                          .toLocalDateTime())
          // Immutables generated GSON Adapters in alphabetical order
          .registerTypeAdapterFactory(new GsonAdaptersDelegations())
          .registerTypeAdapterFactory(new GsonAdaptersDelegationRole())
          .registerTypeAdapterFactory(new GsonAdaptersHashes())
          .registerTypeAdapterFactory(new GsonAdaptersKey())
          .registerTypeAdapterFactory(new GsonAdaptersRekorEntry())
          .registerTypeAdapterFactory(new GsonAdaptersRekorEntryBody())
          .registerTypeAdapterFactory(new GsonAdaptersRoot())
          .registerTypeAdapterFactory(new GsonAdaptersRootMeta())
          .registerTypeAdapterFactory(new GsonAdaptersRootRole())
          .registerTypeAdapterFactory(new GsonAdaptersSignature())
          .registerTypeAdapterFactory(new GsonAdaptersSnapshot())
          .registerTypeAdapterFactory(new GsonAdaptersSnapshotMeta())
          .registerTypeAdapterFactory(new GsonAdaptersTargets())
          .registerTypeAdapterFactory(new GsonAdaptersTargetMeta())
          .registerTypeAdapterFactory(new GsonAdaptersTimestamp())
          .registerTypeAdapterFactory(new GsonAdaptersTimestampMeta())
          .registerTypeAdapterFactory(new GsonAdaptersInTotoPayload())
          .disableHtmlEscaping()
          .create();

  @Override
  public Gson get() {
    return gson;
  }
}