/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project 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.
 */
package org.jboss.netty.handler.codec.http;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.handler.codec.compression.ZlibDecoder;
import org.jboss.netty.handler.codec.compression.ZlibWrapper;
import org.jboss.netty.handler.codec.embedder.DecoderEmbedder;

/**
 * Decompresses an {@link HttpMessage} and an {@link HttpChunk} compressed in
 * {@code gzip} or {@code deflate} encoding.  For more information on how this
 * handler modifies the message, please refer to {@link HttpContentDecoder}.
 */
public class HttpContentDecompressor extends HttpContentDecoder {
    @Override
    protected DecoderEmbedder<ChannelBuffer> newContentDecoder(String contentEncoding) throws Exception {
        if ("gzip".equalsIgnoreCase(contentEncoding) || "x-gzip".equalsIgnoreCase(contentEncoding)) {
            return new DecoderEmbedder<ChannelBuffer>(new ZlibDecoder(ZlibWrapper.GZIP));
        }
        if ("deflate".equalsIgnoreCase(contentEncoding) || "x-deflate".equalsIgnoreCase(contentEncoding)) {
            // To be strict, 'deflate' means ZLIB, but some servers were not implemented correctly.
            return new DecoderEmbedder<ChannelBuffer>(new ZlibDecoder(ZlibWrapper.ZLIB_OR_NONE));
        }

        // 'identity' or unsupported
        return null;
    }
}
