HttpGzipResponseInterceptor.java

/*
    Copyright (C) 2013 Prasanna Thirumalai
    
    This file is part of StackX.

    StackX is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    StackX is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with StackX.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.prasanna.android.http;

import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationTargetException;
import java.util.zip.GZIPInputStream;

import org.apache.http.Header;
import org.apache.http.HeaderElement;
import org.apache.http.HttpEntity;
import org.apache.http.HttpException;
import org.apache.http.HttpResponse;
import org.apache.http.HttpResponseInterceptor;
import org.apache.http.entity.HttpEntityWrapper;
import org.apache.http.protocol.HttpContext;

import com.prasanna.android.utils.LogWrapper;

public class HttpGzipResponseInterceptor implements HttpResponseInterceptor {
  private final String TAG = HttpGzipResponseInterceptor.class.getSimpleName();
  private final Class<? extends HttpEntityWrapper> entityWrapper;
  private final String contentEncoding;

  static class GzipDecompressingEntity extends HttpEntityWrapper {
    public GzipDecompressingEntity(final HttpEntity entity) {
      super(entity);
    }

    @Override
    public InputStream getContent() throws IOException, IllegalStateException {
      return new GZIPInputStream(wrappedEntity.getContent());
    }

    @Override
    public long getContentLength() {
      return -1;
    }
  }

  public HttpGzipResponseInterceptor(final String contentEncoding,
      final Class<? extends HttpEntityWrapper> entityWrapper) {
    this.contentEncoding = contentEncoding;
    this.entityWrapper = entityWrapper;
  }

  @Override
  public void process(HttpResponse response, HttpContext context) throws HttpException, IOException {
    HttpEntity entity = response.getEntity();
    Header encodingHeader = entity.getContentEncoding();
    if (encodingHeader != null) {
      HeaderElement[] codecs = encodingHeader.getElements();
      for (int i = 0; i < codecs.length; i++) {
        if (codecs[i].getName().equalsIgnoreCase(contentEncoding)) {
          try {
            entityWrapper.getConstructor(HttpEntity.class).newInstance(entity);
            response.setEntity(new GzipDecompressingEntity(entity));
            return;
          }
          catch (IllegalArgumentException e) {
            LogWrapper.e(TAG, e.getMessage());
          }
          catch (SecurityException e) {
            LogWrapper.e(TAG, e.getMessage());
          }
          catch (InstantiationException e) {
            LogWrapper.e(TAG, e.getMessage());
          }
          catch (IllegalAccessException e) {
            LogWrapper.e(TAG, e.getMessage());
          }
          catch (InvocationTargetException e) {
            LogWrapper.e(TAG, e.getMessage());
          }
          catch (NoSuchMethodException e) {
            LogWrapper.e(TAG, e.getMessage());
          }
        }
      }
    }
  }

}