netty.syslog.MessageDecoder.java Source code

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Here is the source code for netty.syslog.MessageDecoder.java

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/*
 *   Copyright (c) 2014 Intellectual Reserve, Inc.  All rights reserved.
 *
 *   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 netty.syslog;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;
import io.netty.handler.codec.DecoderException;

import java.time.ZonedDateTime;
import java.util.List;

import static netty.syslog.DecoderUtil.expect;
import static netty.syslog.DecoderUtil.peek;
import static netty.syslog.DecoderUtil.readDigit;
import static netty.syslog.DecoderUtil.readStringToSpace;

public class MessageDecoder extends ByteToMessageDecoder {

    @Override
    protected void decode(ChannelHandlerContext context, ByteBuf buffer, List<Object> objects) throws Exception {
        if (buffer.readableBytes() < 1) {
            return;
        }
        final Message.MessageBuilder messageBuilder = Message.MessageBuilder.create();

        // Decode PRI
        expect(buffer, '<');
        final int pri = readDigit(buffer);
        if (pri < 0 || pri > 191) {
            throw new DecoderException("Invalid PRIVAL " + pri);
        }
        final int facility = pri / 8;
        final int severity = pri % 8;

        messageBuilder.facility(Message.Facility.values()[facility]);
        messageBuilder.severity(Message.Severity.values()[severity]);

        expect(buffer, '>');

        // Decode VERSION
        if (buffer.readByte() != '1') {
            throw new DecoderException("Expected a version 1 syslog message");
        }
        expect(buffer, ' ');

        // Decode TIMESTAMP
        final ZonedDateTime timestamp;
        final String timeStampString = readStringToSpace(buffer, true);
        if (timeStampString == null) {
            timestamp = null;
        } else {
            timestamp = ZonedDateTime.parse(timeStampString);
        }
        messageBuilder.timestamp(timestamp);
        expect(buffer, ' ');

        // Decode HOSTNAME
        messageBuilder.hostname(readStringToSpace(buffer, true));
        expect(buffer, ' ');

        // Decode APP-NAME
        messageBuilder.applicationName(readStringToSpace(buffer, true));
        expect(buffer, ' ');

        // Decode PROC-ID
        messageBuilder.processId(readStringToSpace(buffer, true));
        expect(buffer, ' ');

        // Decode MSGID
        messageBuilder.messageId(readStringToSpace(buffer, true));
        expect(buffer, ' ');

        // TODO Decode structured data
        expect(buffer, '-');
        expect(buffer, ' ');

        final int length = buffer.readableBytes();
        messageBuilder.content(buffer.slice(buffer.readerIndex(), length).retain());
        buffer.skipBytes(length);

        objects.add(messageBuilder.build());
    }

}