com.linkedin.restli.client.multiplexer.MultiplexedCallback Maven / Gradle / Ivy

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Pegasus is a framework for building robust, scalable service architectures using dynamic discovery and simple asychronous type-checked REST + JSON APIs.
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/*
   Copyright (c) 2015 LinkedIn Corp.

   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.linkedin.restli.client.multiplexer;


import com.linkedin.common.callback.Callback;
import com.linkedin.data.ByteString;
import com.linkedin.data.template.GetMode;
import com.linkedin.r2.message.rest.RestException;
import com.linkedin.r2.message.rest.RestResponse;
import com.linkedin.r2.message.rest.RestResponseBuilder;
import com.linkedin.r2.message.rest.RestStatus;
import com.linkedin.restli.client.Response;
import com.linkedin.restli.client.RestLiDecodingException;
import com.linkedin.restli.common.multiplexer.IndividualBody;
import com.linkedin.restli.common.multiplexer.IndividualResponse;
import com.linkedin.restli.common.multiplexer.IndividualResponseMap;
import com.linkedin.restli.common.multiplexer.MultiplexedResponseContent;
import com.linkedin.restli.internal.client.EntityResponseDecoder;
import com.linkedin.restli.internal.common.CookieUtil;
import com.linkedin.restli.internal.common.DataMapConverter;
import com.linkedin.restli.internal.common.HeaderUtil;

import java.io.IOException;
import java.util.Map;

import javax.activation.MimeTypeParseException;


/**
 * Converts multiplexed callbacks (aggregated and individual) into a REST response callback.
 *
 * @author Dmitriy Yefremov
 */
public class MultiplexedCallback implements Callback
{
  private final EntityResponseDecoder _decoder = new EntityResponseDecoder(MultiplexedResponseContent.class);
  private final Map> _callbacks;
  private final Callback _aggregatedCallback;

  public MultiplexedCallback(Map> callbacks, Callback aggregatedCallback)
  {
    _callbacks = callbacks;
    _aggregatedCallback = aggregatedCallback;
  }

  @Override
  public void onError(Throwable e)
  {
    // individual callbacks are notified first
    for (Callback callback : _callbacks.values())
    {
      callback.onError(e);
    }
    // aggregated callback is guaranteed to be called after all individual callbacks
    _aggregatedCallback.onError(e);
  }

  @Override
  public void onSuccess(RestResponse restResponse)
  {
    Response response;
    try
    {
      response = _decoder.decodeResponse(restResponse);
    }
    catch (RestLiDecodingException e)
    {
      onError(e);
      return;
    }
    // individual callbacks are notified first
    notifyIndividualCallbacks(response);
    // aggregated callback is guaranteed to be called after all individual callbacks
    notifyAggregatedCallback(response);
  }

  private void notifyIndividualCallbacks(Response muxResponse)
  {
    IndividualResponseMap individualResponses = muxResponse.getEntity().getResponses();
    for (IndividualResponseMap.Entry individualResponseMapEntry : individualResponses.entrySet())
    {
      Integer id = Integer.valueOf(individualResponseMapEntry.getKey());
      IndividualResponse individualResponse = individualResponseMapEntry.getValue();
      Callback callback = _callbacks.get(id);
      RestResponse individualRestResponse;
      try
      {
        individualRestResponse = buildIndividualRestResponse(muxResponse, individualResponse);
      }
      catch (MimeTypeParseException e)
      {
        callback.onError(new RestLiDecodingException("Could not convert IndividualResponse to individual RestRestponse due to an invalid content type, id=" + id, e));
        return;
      }
      catch (IOException e)
      {
        callback.onError(new RestLiDecodingException("Could not convert IndividualResponse to individual RestRestponse, id=" + id, e));
        return;
      }

      if (RestStatus.isOK(individualResponse.getStatus()))
      {
        callback.onSuccess(individualRestResponse);
      }
      else
      {
        RestException exception = new RestException(individualRestResponse, "Received error " + individualRestResponse.getStatus());
        callback.onError(exception);
      }
    }
  }

  private static RestResponse buildIndividualRestResponse(Response envelopeResponse, IndividualResponse individualResponse) throws IOException, MimeTypeParseException
  {
    IndividualBody body = individualResponse.getBody(GetMode.NULL);
    ByteString entity = (body != null) ? DataMapConverter.dataMapToByteString(individualResponse.getHeaders(), body.data()) : ByteString.empty();

    return new RestResponseBuilder()
      .setStatus(individualResponse.getStatus())
      .setHeaders(inheritHeaders(individualResponse, envelopeResponse))
      .setCookies(CookieUtil.encodeSetCookies(envelopeResponse.getCookies()))
      .setEntity(entity)
      .build();
  }

  private static Map inheritHeaders(IndividualResponse individualResponse, Response envelopeResponse)
  {
    Map envelopeHeaders = HeaderUtil.removeHeaders(envelopeResponse.getHeaders(), HeaderUtil.NONINHERITABLE_RESPONSE_HEADERS);
    return HeaderUtil.mergeHeaders(envelopeHeaders, individualResponse.getHeaders());
  }

  private void notifyAggregatedCallback(Response response)
  {
    MultiplexedResponse muxResponse = new MultiplexedResponse(response.getStatus(), response.getHeaders());
    _aggregatedCallback.onSuccess(muxResponse);
  }
}