dubbo协议
dubbo协议说明
协议头约定
请參考dubbo开发人员指南
解释
协议格式 header body data
协议头是16字节的定长数据。參见上图dubbo,16*8=128,地址范围0~127
- 2字节magic字符串0xdabb,0-7高位,8-15低位
- 1字节的消息标志位。16-20序列id,21 event,22 two way,23请求或响应标识
- 1字节状态。当消息类型为响应时。设置响应状态。24-31位。
- 8字节,消息ID,long类型,32-95位。
- 4字节,消息长度,96-127位
源码參考
com.alibaba.dubbo.remoting.exchange.codec.ExchangeCodec
protected void encodeRequest(Channel channel, ChannelBuffer buffer, Request req) throws IOException {
Serialization serialization = getSerialization(channel);
// header.
byte[] header = new byte[HEADER_LENGTH];
// set magic number.
Bytes.short2bytes(MAGIC, header);
// set request and serialization flag.
header[2] = (byte) (FLAG_REQUEST | serialization.getContentTypeId());
if (req.isTwoWay()) header[2] |= FLAG_TWOWAY;
if (req.isEvent()) header[2] |= FLAG_EVENT;
// set request id.
Bytes.long2bytes(req.getId(), header, 4);
// encode request data.
int savedWriteIndex = buffer.writerIndex();
buffer.writerIndex(savedWriteIndex + HEADER_LENGTH);
ChannelBufferOutputStream bos = new ChannelBufferOutputStream(buffer);
ObjectOutput out = serialization.serialize(channel.getUrl(), bos);
if (req.isEvent()) {
encodeEventData(channel, out, req.getData());
} else {
encodeRequestData(channel, out, req.getData());
}
out.flushBuffer();
bos.flush();
bos.close();
int len = bos.writtenBytes();
checkPayload(channel, len);
Bytes.int2bytes(len, header, 12);
// write
buffer.writerIndex(savedWriteIndex);
buffer.writeBytes(header); // write header.
buffer.writerIndex(savedWriteIndex + HEADER_LENGTH + len);
}
posted on 2017-07-01 20:58 yjbjingcha 阅读(187) 评论(0) 编辑 收藏 举报