content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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
   *
   *     https://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 org.apache.avro.tool;
  
  import org.apache.avro.Protocol;
  import org.apache.avro.io.BinaryEncoder;
  import org.apache.avro.io.DatumReader;
  import org.apache.avro.io.DatumWriter;
  import org.apache.avro.io.DecoderFactory;
  import org.apache.avro.io.EncoderFactory;
  import org.apache.avro.ipc.HandshakeRequest;
  import org.apache.avro.ipc.HandshakeResponse;
  import org.apache.avro.ipc.Ipc;
  import org.apache.avro.ipc.MD5;
  import org.apache.avro.ipc.Transceiver;
  import org.apache.avro.specific.SpecificDatumReader;
  import org.apache.avro.specific.SpecificDatumWriter;
  import org.apache.avro.util.ByteBufferInputStream;
  import org.apache.avro.util.ByteBufferOutputStream;
  
  import java.io.InputStream;
  import java.io.PrintStream;
  import java.net.URI;
  import java.nio.ByteBuffer;
  import java.util.LinkedHashMap;
  import java.util.List;
  
  /**
   * Tool to grab the protocol from a remote running service.
   */
  public class RpcProtocolTool implements Tool {
  
    @Override
    public String getName() {
      return "rpcprotocol";
    }
  
    @Override
    public String getShortDescription() {
      return "Output the protocol of a RPC service";
    }
  
    @Override
    public int run(InputStream in, PrintStream out, PrintStream err, List<String> args) throws Exception {
  
      if (args.size() != 1) {
        err.println("Usage: uri");
        return 1;
      }
  
      URI uri = URI.create(args.get(0));
  
      try (Transceiver transceiver = Ipc.createTransceiver(uri)) {
  
        // write an empty HandshakeRequest
        HandshakeRequest rq = HandshakeRequest.newBuilder().setClientHash(new MD5(new byte[16]))
            .setServerHash(new MD5(new byte[16])).setClientProtocol(null).setMeta(new LinkedHashMap<>()).build();
  
        DatumWriter<HandshakeRequest> handshakeWriter = new SpecificDatumWriter<>(HandshakeRequest.class);
  
        ByteBufferOutputStream byteBufferOutputStream = new ByteBufferOutputStream();
  
        BinaryEncoder encoder = EncoderFactory.get().binaryEncoder(byteBufferOutputStream, null);
  
        handshakeWriter.write(rq, encoder);
        encoder.flush();
  
        // send it and get the response
        List<ByteBuffer> response = transceiver.transceive(byteBufferOutputStream.getBufferList());
  
        // parse the response
        ByteBufferInputStream byteBufferInputStream = new ByteBufferInputStream(response);
  
        DatumReader<HandshakeResponse> handshakeReader = new SpecificDatumReader<>(HandshakeResponse.class);
  
        HandshakeResponse handshakeResponse = handshakeReader.read(null,
            DecoderFactory.get().binaryDecoder(byteBufferInputStream, null));
  
        Protocol p = Protocol.parse(handshakeResponse.getServerProtocol());
  
        // finally output the protocol
        out.println(p.toString(true));
  
      }
      return 0;
    }
  }
  