/*
 * 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 com.codahale.grpcproxy;

import io.grpc.stub.ServerCalls.UnaryMethod;
import io.grpc.stub.StreamObserver;
import java.io.IOException;
import okhttp3.HttpUrl;
import okhttp3.MediaType;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

/**
 * Proxies a gRPC request to an HTTP backend.
 */
class ProxyUnaryMethod implements UnaryMethod<byte[], byte[]> {

  private static final MediaType OCTET_STREAM = MediaType.parse("application/octet-stream");
  private final OkHttpClient client;
  private final HttpUrl url;

  ProxyUnaryMethod(OkHttpClient client, HttpUrl backend, String methodName) {
    this.client = client;
    this.url = backend.newBuilder().addQueryParameter("method", methodName).build();
  }

  @Override
  public void invoke(byte[] msg, StreamObserver<byte[]> responseObserver) {
    final Request req = new Request.Builder().url(url)
                                             .post(RequestBody.create(OCTET_STREAM, msg))
                                             .build();
    try {
      try (Response response = client.newCall(req).execute()) {
        responseObserver.onNext(response.body().bytes());
      }
      responseObserver.onCompleted();
    } catch (IOException e) {
      responseObserver.onError(e);
    }
  }
}

/*
 * 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 com.codahale.grpcproxy;

import io.grpc.stub.ServerCalls.UnaryMethod;
import io.grpc.stub.StreamObserver;
import java.io.IOException;
import okhttp3.HttpUrl;
import okhttp3.MediaType;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;
import okhttp3.ResponseBody;

/**
 * Proxies a gRPC request to an HTTP backend.
 */
class ProxyUnaryMethod implements UnaryMethod<byte[], byte[]> {

  private static final MediaType OCTET_STREAM = MediaType.parse("application/octet-stream");
  private final OkHttpClient client;
  private final HttpUrl url;

  ProxyUnaryMethod(OkHttpClient client, HttpUrl backend, String methodName) {
    this.client = client;
    this.url = backend.newBuilder().addQueryParameter("method", methodName).build();
  }

  @Override
  public void invoke(byte[] msg, StreamObserver<byte[]> responseObserver) {
    final Request req = new Request.Builder().url(url)
                                             .post(RequestBody.create(OCTET_STREAM, msg))
                                             .build();
    try {
      try (Response response = client.newCall(req).execute()) {
        final ResponseBody body = response.body();
        if (body != null) {
          responseObserver.onNext(body.bytes());
        }
      }
      responseObserver.onCompleted();
    } catch (IOException e) {
      responseObserver.onError(e);
    }
  }
}

Fix possible NPE.