/**
* Returns a new {@link EmbeddedChannel} that decodes the HTTP2 message content encoded in the
* specified {@code contentEncoding}.
*
* @param contentEncoding the value of the {@code content-encoding} header
* @return a new {@link ByteToMessageDecoder} if the specified encoding is supported. {@code null}
* otherwise (alternatively, you can throw a {@link Http2Exception} to block unknown
* encoding).
* @throws Http2Exception If the specified encoding is not not supported and warrants an exception
*/
protected EmbeddedChannel newContentDecoder(CharSequence contentEncoding) throws Http2Exception {
if (GZIP.equalsIgnoreCase(contentEncoding) || XGZIP.equalsIgnoreCase(contentEncoding)) {
return new EmbeddedChannel(ZlibCodecFactory.newZlibDecoder(ZlibWrapper.GZIP));
}
if (DEFLATE.equalsIgnoreCase(contentEncoding) || XDEFLATE.equalsIgnoreCase(contentEncoding)) {
final ZlibWrapper wrapper = strict ? ZlibWrapper.ZLIB : ZlibWrapper.ZLIB_OR_NONE;
// To be strict, 'deflate' means ZLIB, but some servers were not implemented correctly.
return new EmbeddedChannel(ZlibCodecFactory.newZlibDecoder(wrapper));
}
// 'identity' or unsupported
return null;
}
public static InputStream decode(String codings, InputStream content)
throws IOException, MessageFormatException {
if (codings == null || codings.trim().equals("")) return content;
String[] algos = codings.split("[ \t]*,[ \t]*");
if (algos.length == 1 && IDENTITY.equalsIgnoreCase(algos[0])) return content;
for (int i = 0; i < algos.length; i++) {
if (CHUNKED.equalsIgnoreCase(algos[i])) {
content = new ChunkedInputStream(content);
} else if (DEFLATE.equalsIgnoreCase(algos[i])) {
content = new DeflaterInputStream(content);
} else if (GZIP.equalsIgnoreCase(algos[i])) {
content = new GunzipInputStream(content);
} else if (IDENTITY.equalsIgnoreCase(algos[i])) {
// nothing to do
} else throw new MessageFormatException("Unsupported coding : " + algos[i]);
}
return content;
}
