/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. 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
*
* 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. For additional information regarding
* copyright in this work, please see the NOTICE file in the top level
* directory of this distribution.
*/
package org.apache.abdera.protocol.server.filters;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.DeflaterOutputStream;
import org.apache.abdera.protocol.server.Filter;
import org.apache.abdera.protocol.server.FilterChain;
import org.apache.abdera.protocol.server.ProviderHelper;
import org.apache.abdera.protocol.server.RequestContext;
import org.apache.abdera.protocol.server.ResponseContext;
import org.apache.abdera.protocol.server.context.ResponseContextWrapper;
import org.apache.abdera.util.CompressionUtil;
import org.apache.abdera.util.CompressionUtil.CompressionCodec;
import org.apache.abdera.writer.Writer;
/**
* Abdera Filter implementation that selectively applies compression to the
* response payload
*/
public class CompressionFilter
implements Filter {
public ResponseContext filter(
RequestContext request,
FilterChain chain) {
String encoding = request.getHeader("Accept-Encoding");
String[] encodings =
encoding != null ?
ProviderHelper.orderByQ(encoding) :
new String[0];
for (String enc : encodings) {
try {
CompressionCodec codec = CompressionCodec.valueOf(enc.toUpperCase());
return new CompressingResponseContextWrapper(chain.next(request), codec);
} catch (Exception e) {}
}
return chain.next(request);
}
/**
* A HttpServletResponseWrapper implementation that applies GZip or Deflate
* compression to response output.
*/
public static class CompressingResponseContextWrapper
extends ResponseContextWrapper {
private final CompressionCodec codec;
public CompressingResponseContextWrapper(
ResponseContext response,
CompressionCodec codec) {
super(response);
this.codec = codec;
}
private OutputStream wrap(OutputStream out) {
return new CompressingOutputStream(codec, out);
}
public void writeTo(
OutputStream out,
Writer writer)
throws IOException {
out = wrap(out);
super.writeTo(out, writer);
out.flush();
}
public void writeTo(
OutputStream out)
throws IOException {
out = wrap(out);
super.writeTo(out);
out.flush();
}
}
public static class CompressingOutputStream
extends FilterOutputStream {
public CompressingOutputStream(
CompressionCodec codec,
OutputStream out) {
super(initStream(codec,out));
}
public CompressingOutputStream(DeflaterOutputStream dout) {
super(dout);
}
private static OutputStream initStream(
CompressionCodec codec,
OutputStream out) {
try {
return CompressionUtil.getEncodedOutputStream(out, codec);
} catch (Exception e) {
return out;
}
}
}
}