本文基于networkcomms2.3.1开源版本 gplv3协议
我们先回顾一个 c#网络通信框架networkcomms内核解析之六 处理接收到的二进制数据 中，主程序把PacketBuilder 中的数据交给核心处理器处理的过程
//创建优先级队列项目
PriorityQueueItem item = new PriorityQueueItem(priority, this, topPacketHeader, packetBuilder.ReadDataSection(packetHeaderSize, topPacketHeader.PayloadPacketSize), incomingPacketSendReceiveOptions);
NetworkComms.CompleteIncomingItemTask(item);上面的代码中
第一行 生成了一个优先级队列项目 （主要方便交给带有优先级的自定义线程池进行处理)
其参数包括
1：优先级 2：相关Tcp连接 （有返回数据的话，还要通过此连接返回) 3:数据包包头 4：数据包的二进制数据（内存流，还没有解析成数据包，留待下一步解析）。
自定义线程池，暂时不表，看一下核心处理器。（自定义线程池，是创建多个线程，并按照优先级对数据进行处理）
NetworkComms.CompleteIncomingItemTask(item);/// <summary>
/// Once we have received all incoming data we handle it further. This is performed at the global level to help support different priorities.
/// 数据包的核心处理器
/// </summary>
/// <param name="itemAsObj">Possible PriorityQueueItem. If null is provided an item will be removed from the global item queue</param>
internal static void CompleteIncomingItemTask(object itemAsObj)
{
if (itemAsObj == null)
throw new ArgumentNullException("itemAsObj", "Provided parameter itemAsObj cannot be null.");
//优先级队列项目
PriorityQueueItem item = null;
try
{
//If the packetBytes are null we need to ask the incoming packet queue for what we should be running
//把对象还原成优先级队列项目
item = itemAsObj as PriorityQueueItem;
if (item == null)
throw new InvalidCastException("Cast from object to PriorityQueueItem resulted in null reference, unable to continue.");
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace("Handling a " + item.PacketHeader.PacketType + " packet from " + item.Connection.ConnectionInfo + " with a priority of " + item.Priority.ToString() + ".");
#if !WINDOWS_PHONE
if (Thread.CurrentThread.Priority != (ThreadPriority)item.Priority) Thread.CurrentThread.Priority = (ThreadPriority)item.Priority;
#endif
//Check for a shutdown connection
if (item.Connection.ConnectionInfo.ConnectionState == ConnectionState.Shutdown) return;
//We only look at the check sum if we want to and if it has been set by the remote end
//如果这是一个检验和消息
if (NetworkComms.EnablePacketCheckSumValidation && item.PacketHeader.ContainsOption(PacketHeaderStringItems.CheckSumHash))
{
var packetHeaderHash = item.PacketHeader.GetOption(PacketHeaderStringItems.CheckSumHash);
//Validate the checkSumhash of the data
string packetDataSectionMD5 = NetworkComms.MD5Bytes(item.DataStream);
if (packetHeaderHash != packetDataSectionMD5)
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Warn(" ... corrupted packet detected, expected " + packetHeaderHash + " but received " + packetDataSectionMD5 + ".");
//We have corruption on a resend request, something is very wrong so we throw an exception.
if (item.PacketHeader.PacketType == Enum.GetName(typeof(ReservedPacketType), ReservedPacketType.CheckSumFailResend)) throw new CheckSumException("Corrupted md5CheckFailResend packet received.");
if (item.PacketHeader.PayloadPacketSize < NetworkComms.CheckSumMismatchSentPacketCacheMaxByteLimit)
{
//Instead of throwing an exception we can request the packet to be resent
Packet returnPacket = new Packet(Enum.GetName(typeof(ReservedPacketType), ReservedPacketType.CheckSumFailResend), packetHeaderHash, NetworkComms.InternalFixedSendReceiveOptions);
item.Connection.SendPacket(returnPacket);
//We need to wait for the packet to be resent before going further
return;
}
else
throw new CheckSumException("Corrupted packet detected from " + item.Connection.ConnectionInfo + ", expected " + packetHeaderHash + " but received " + packetDataSectionMD5 + ".");
}
}
//Remote end may have requested packet receive confirmation so we send that now
//如果对象发送的消息，需要确认收到，在此处进行确认
if (item.PacketHeader.ContainsOption(PacketHeaderStringItems.ReceiveConfirmationRequired))
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... sending requested receive confirmation packet.");
var hash = item.PacketHeader.ContainsOption(PacketHeaderStringItems.CheckSumHash) ? item.PacketHeader.GetOption(PacketHeaderStringItems.CheckSumHash) : "";
Packet returnPacket = new Packet(Enum.GetName(typeof(ReservedPacketType), ReservedPacketType.Confirmation), hash, NetworkComms.InternalFixedSendReceiveOptions);
item.Connection.SendPacket(returnPacket);
}
//处理保留数据类型的数据包
//We can now pass the data onto the correct delegate
//First we have to check for our reserved packet types
//The following large sections have been factored out to make reading and debugging a little easier
if (item.PacketHeader.PacketType == Enum.GetName(typeof(ReservedPacketType), ReservedPacketType.CheckSumFailResend))
item.Connection.CheckSumFailResendHandler(item.DataStream);
else if (item.PacketHeader.PacketType == Enum.GetName(typeof(ReservedPacketType), ReservedPacketType.ConnectionSetup))
item.Connection.ConnectionSetupHandler(item.DataStream);
else if (item.PacketHeader.PacketType == Enum.GetName(typeof(ReservedPacketType), ReservedPacketType.AliveTestPacket) &&
(NetworkComms.InternalFixedSendReceiveOptions.DataSerializer.DeserialiseDataObject<byte[]>(item.DataStream,
NetworkComms.InternalFixedSendReceiveOptions.DataProcessors,
NetworkComms.InternalFixedSendReceiveOptions.Options))[0] == 0)
{
//If we have received a ping packet from the originating source we reply with true
Packet returnPacket = new Packet(Enum.GetName(typeof(ReservedPacketType), ReservedPacketType.AliveTestPacket), new byte[1] { 1 }, NetworkComms.InternalFixedSendReceiveOptions);
item.Connection.SendPacket(returnPacket);
}
//We allow users to add their own custom handlers for reserved packet types here
//else
if (true)
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace("Triggering handlers for packet of type '" + item.PacketHeader.PacketType + "' from " + item.Connection.ConnectionInfo);
//We trigger connection specific handlers first
//触发连接上的消息处理器
bool connectionSpecificHandlersTriggered = item.Connection.TriggerSpecificPacketHandlers(item.PacketHeader, item.DataStream, item.SendReceiveOptions);
//We trigger global handlers second
//触发具体的数据包处理器
NetworkComms.TriggerGlobalPacketHandlers(item.PacketHeader, item.Connection, item.DataStream, item.SendReceiveOptions, connectionSpecificHandlersTriggered);
}
}
catch (CommunicationException)
{
if (item != null)
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Fatal("A communcation exception occured in CompleteIncomingPacketWorker(), connection with " + item.Connection.ConnectionInfo + " be closed.");
item.Connection.CloseConnection(true, 2);
}
}
catch (DuplicateConnectionException ex)
{
if (item != null)
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Warn(ex.Message != null ? ex.Message : "A possible duplicate connection was detected with " + item.Connection + ". Closing connection.");
item.Connection.CloseConnection(true, 42);
}
}
catch (Exception ex)
{
NetworkComms.LogError(ex, "CompleteIncomingItemTaskError");
if (item != null)
{
//If anything goes wrong here all we can really do is log the exception
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Fatal("An unhandled exception occured in CompleteIncomingPacketWorker(), connection with " + item.Connection.ConnectionInfo + " be closed. See log file for more information.");
item.Connection.CloseConnection(true, 3);
}
}
finally
{
//We need to dispose the data stream correctly
if (item!=null) item.DataStream.Close();
#if !WINDOWS_PHONE
//Ensure the thread returns to the pool with a normal priority
if (Thread.CurrentThread.Priority != ThreadPriority.Normal) Thread.CurrentThread.Priority = ThreadPriority.Normal;
#endif
}
}
上面的方法中，我们看到TriggerGlobalPacketHandlers方法，此方法把数据包，和我们在服务器端自定义的数据包处理器关联起来，并用数据包处理器对数据包进行处理
//触发具体的数据包处理器
NetworkComms.TriggerGlobalPacketHandlers(item.PacketHeader, item.Connection, item.DataStream, item.SendReceiveOptions, connectionSpecificHandlersTriggered);我们看一下此方法的具体内容：
internal static void TriggerGlobalPacketHandlers(PacketHeader packetHeader, Connection connection, MemoryStream incomingDataStream, SendReceiveOptions options, bool ignoreUnknownPacketTypeOverride = false)
{
try
{
if (options == null) throw new PacketHandlerException("Provided sendReceiveOptions should not be null for packetType " + packetHeader.PacketType);
//We take a copy of the handlers list incase it is modified outside of the lock
List<IPacketTypeHandlerDelegateWrapper> handlersCopy = null;
lock (globalDictAndDelegateLocker)
if (globalIncomingPacketHandlers.ContainsKey(packetHeader.PacketType))
//根据数据包包头中的消息类型，获取相关的自定义处理器，处理器可以一个，可以多个，当然一般是一个：）
handlersCopy = new List<IPacketTypeHandlerDelegateWrapper>(globalIncomingPacketHandlers[packetHeader.PacketType]);
if (handlersCopy == null && !IgnoreUnknownPacketTypes && !ignoreUnknownPacketTypeOverride)
{
//We may get here if we have not added any custom delegates for reserved packet types
bool isReservedType = false;
for (int i = 0; i < reservedPacketTypeNames.Length; i++)
{
if (reservedPacketTypeNames[i] == packetHeader.PacketType)
{
isReservedType = true;
break;
}
}
if (!isReservedType)
{
//Change this to just a log because generally a packet of the wrong type is nothing to really worry about
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Warn("The received packet type '" + packetHeader.PacketType + "' has no configured handler and network comms is not set to ignore unknown packet types. Set NetworkComms.IgnoreUnknownPacketTypes=true to prevent this error.");
LogError(new UnexpectedPacketTypeException("The received packet type '" + packetHeader.PacketType + "' has no configured handler and network comms is not set to ignore unknown packet types. Set NetworkComms.IgnoreUnknownPacketTypes=true to prevent this error."), "PacketHandlerErrorGlobal_" + packetHeader.PacketType);
}
return;
}
else if (handlersCopy == null && (IgnoreUnknownPacketTypes || ignoreUnknownPacketTypeOverride))
//If we have received and unknown packet type and we are choosing to ignore them we just finish here
return;
else
{
//Idiot check
if (handlersCopy.Count == 0)
throw new PacketHandlerException("An entry exists in the packetHandlers list but it contains no elements. This should not be possible.");
//Deserialise the object only once
//把数据包解析处理
object returnObject = handlersCopy[0].DeSerialize(incomingDataStream, options);
//Pass the data onto the handler and move on.
if (LoggingEnabled) logger.Trace(" ... passing completed data packet of type '" + packetHeader.PacketType + "' to " + handlersCopy.Count.ToString() + " selected global handlers.");
//Pass the object to all necessary delgates
//We need to use a copy because we may modify the original delegate list during processing
foreach (IPacketTypeHandlerDelegateWrapper wrapper in handlersCopy)
{
try
{
//用数据包数据里处理数据包
//这里的处理器，就是我们自定义的处理器了
wrapper.Process(packetHeader, connection, returnObject);
}
catch (Exception ex)
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Fatal("An unhandled exception was caught while processing a packet handler for a packet type '" + packetHeader.PacketType + "'. Make sure to catch errors in packet handlers. See error log file for more information.");
NetworkComms.LogError(ex, "PacketHandlerErrorGlobal_" + packetHeader.PacketType);
}
}
if (LoggingEnabled) logger.Trace(" ... all handlers for packet of type '" + packetHeader.PacketType + "' completed.");
}
}
catch (Exception ex)
{
//If anything goes wrong here all we can really do is log the exception
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Fatal("An exception occured in TriggerPacketHandler() for a packet type '" + packetHeader.PacketType + "'. See error log file for more information.");
NetworkComms.LogError(ex, "PacketHandlerErrorGlobal_" + packetHeader.PacketType);
}
}什么是自定义的数据包处理器呢？
举个例子
客户端我们这么写：
ResMsgContract resMsg = newTcpConnection.SendReceiveObject<ResMsgContract>("ReqLogin", "ResLogin", 5000, contract);服务器端我们就要写一个对应的自定义数据包处理器，写法如下：
首先要注册自定义的数据包处理器：
NetworkComms.AppendGlobalIncomingPacketHandler<LoginContract>("ReqLogin", IncomingLoginRequest);
private void IncomingLoginRequest(PacketHeader header, Connection connection, LoginContract loginContract)
{
try
{
string resMsg="";
//为了简单，这里不调用数据库，而是模拟一下登录
if (loginContract.UserID == "1000" && loginContract.PassWord == "123")
resMsg = "登录成功";
else
resMsg = "用户名密码错误";
//把返回结果写入到契约类中，后面返回给客户端
ResMsgContract contract = new ResMsgContract();
contract.Message = resMsg;
connection.SendObject("ResLogin", contract);
}
catch (Exception ex)
{
}
}
通过上面的注册语句，Netowrkcomms中就把消息类型“ReqLogin"与他对应的处理方法关联起来，当以后服务器收到数据包包头中消息类型为"ReqLogin"类型的消息，就知道调用哪个方法来进行处理.
下一篇分析一下，自定义数据包处理器的底层运行机制
www.cnblogs.com/networkcomms
www.networkcomms.cn
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