io.sipstack.netty.codec.sip

Class SipMessageDatagramDecoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.handler.codec.MessageToMessageDecoder<io.netty.channel.socket.DatagramPacket>

io.sipstack.netty.codec.sip.SipMessageDatagramDecoder

All Implemented Interfaces:

io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler

public final class SipMessageDatagramDecoder
extends io.netty.handler.codec.MessageToMessageDecoder<io.netty.channel.socket.DatagramPacket>

The SipMessageDatagramDecoder will frame an incoming UDP packet into a SipMessage. Since the data will only be framed, only very minimal checking of whether the data is actually a valid SIP message or not will be performed. It is up to the user to validate the SipMessage through the method SipMessage.verify(). The philosophy is to simply just frame things as fast as possible and then do lazy parsing as much as possible.

Author:

[email protected]

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

io.netty.channel.ChannelHandler.Sharable

Constructor Summary

Constructors

Constructor and Description
SipMessageDatagramDecoder()
SipMessageDatagramDecoder(Clock clock)

Method Summary

Modifier and Type	Method and Description
protected void	decode(io.netty.channel.ChannelHandlerContext ctx, io.netty.channel.socket.DatagramPacket msg, java.util.List<java.lang.Object> out) Framing an UDP packet is much simpler than for a stream based protocol like TCP.

Methods inherited from class io.netty.handler.codec.MessageToMessageDecoder

acceptInboundMessage, channelRead

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelActive, channelInactive, channelReadComplete, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught, userEventTriggered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

handlerAdded, handlerRemoved, isSharable

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.netty.channel.ChannelHandler

handlerAdded, handlerRemoved

Constructor Detail

SipMessageDatagramDecoder

public SipMessageDatagramDecoder()

SipMessageDatagramDecoder

public SipMessageDatagramDecoder(Clock clock)

Method Detail

decode

protected void decode(io.netty.channel.ChannelHandlerContext ctx,
                      io.netty.channel.socket.DatagramPacket msg,
                      java.util.List<java.lang.Object> out)
               throws java.lang.Exception

Framing an UDP packet is much simpler than for a stream based protocol like TCP. We just assumes that everything is correct and therefore all is needed is to read the first line, which is assumed to be a SIP initial line, then read all headers as one big block and whatever is left better be the payload (if there is one). Of course, things do go wrong. If e.g. the UDP packet is fragmented, then we may end up with a partial SIP message but the user can either decide to double check things by calling SipMessage.verify() or the user will eventually notice when trying to access partial headers etc.

Specified by:

decode in class io.netty.handler.codec.MessageToMessageDecoder<io.netty.channel.socket.DatagramPacket>

Throws:

java.lang.Exception