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TCP Socket Server by CoderLaureate

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Author: Archive | Viewed: 760 times | Language: BlitzMax | Category: Multiplayer Code

Rem

Title:   TCPSocket Server
	
	Author:  Jim Pishlo  (CoderLaureate)
	            (J9T@Jimmy9Toes.com)
	
End Rem

Strict

Type TCPSocketServer
	
	'Properties
	Field MyPort:Int = 3849
	Field MySocket:TSocket
	Field MyStream:TSocketStream
	Field Connections:TList = New TList
	Field StopSeq:String = "~r~n"
	
	'Callback handles
	Field NewConnectionCallback(Conn:TCPSocketConnection)
	Field MsgRcvdCallback(Conn:TCPSocketConnection)
	Field LostConnectionCallback(Conn:TCPSocketConnection)
	
	'Constructor (for lack of a better word)
	Function Create:TCPSocketServer(_Port:Int = 3849)
		Local s:TCPSocketServer = New TCPSocketServer
		s.MyPort = _Port
		s.MySocket = CreateTCPSocket()
		s.MyStream = CreateSocketStream(s.MySocket)
		s.MySocket.Bind(_Port)
		s.MySocket.Listen(0)
		Return s
	End Function
	
	'The main method.
	'Monitors connections and triggers events.
	Method Listen()
		Local newConn:TSocket = MySocket.Accept(0)
		If newConn <> Null Then
			Local conn:TCPSocketConnection = TCPSocketConnection.Create(Self,newConn)
			'Add the new connection to the collection
			Connections.AddLast(conn)
			'If a callback has been assigned call it.
			If NewConnectionCallback <> Null Then
				NewConnectionCallback(conn)	'Pass a refernce to the new connection
			End If
		End If
		
		'Clean up closed connections
		For Local c:TCPSocketConnection = EachIn Connections
			If Not c.MySocket.Connected() Then
				If LostConnectionCallback <> Null Then
					LostConnectionCallback(c)
				End If
				Connections.Remove(c)	'Remove connection from collection
			End If
		Next
		
		'Receive Data from connections
		'Trigger callback if neccesary
		For Local c:TCPSocketConnection = EachIn Connections
			If c.MySocket.Connected() Then
				Local t:String = c.Receive()
				If t <> "" Then
					If MsgRcvdCallback <> Null Then
						MsgRcvdCallback(c)
						c.Buffer = ""
					End If
				End If
			End If
		Next 
	End Method
	
	Method Broadcast(Message:String, Conn:TCPSocketConnection = Null)
		If Conn <> Null Then
			Conn.Send(Message)
		Else
			Local c:TCPSocketConnection
			For c = EachIn Connections
				If c.MySocket.Connected() Then
					c.Send(Message)
				End If
			Next
		End If	
	End Method
	
End Type

Type TCPSocketConnection
	Field MyID:String
	Field MyServer:TCPSocketServer
	Field MySocket:TSocket
	Field MyStream:TSocketStream
	Field Buffer:String = ""
	Field StopSeq:String
	
	Function Create:TCPSocketConnection(s:TCPSocketServer, NewSocket:TSocket)
		Local c:TCPSocketConnection = New TCPSocketConnection
		c.MyServer = s
		c.MySocket = NewSocket
		c.MyStream = CreateSocketStream(c.MySocket)
		c.StopSeq = c.MyServer.StopSeq
		c.MyID = DottedIP(c.MySocket.RemoteIP())
		Return c
	End Function

Method Send(Text:String)
		MySTream.WriteString(Text)
	End Method

Method Receive:String()
		Local nBytes:Int = MySocket.ReadAvail()
		Local s:String = StopSeq
		If nBytes Then
			Local in:String = ReadString(MyStream,nBytes)
			Buffer:+ in
			If Buffer.Length >= s.Length And Right$(Buffer,s.Length) = s Then
				Local t:String = Buffer.Replace(s,"") 'Strip out the stop sequence
				Return t
			End If
		End If
	End Method
	
End Type

Function CreateTCPSocketServer:TCPSocketServer(_Port:Int = 3849)
	Return TCPSocketServer.Create(_Port)
End Function

'Test Code:  This is a simple Telnet Chat Server.  Run this program, then
'            open up a command prompt and type:
'  
'				Telnet localhost 3849
'
'			 You can telnet into this server from anywhere in the world
'            and do *very basic* text chatting.  To log in from another
'            computer, type:
'
'				Telnet {host computer ip} 3849
'
'			 This is just a sample program to show you what you can do
'			 with the TCPSocketServer object.
'----------------------------------------------------------------------

'Create callback functions for interaction with the TCPSocketServer Object.

'Function to handle data recieved by server
'------------------------------------------
Function TextHandler(C:TCPSocketConnection)
	C.MyServer.BroadCast(C.MyID + ": " + C.Buffer)
End Function

'Greet new users and assign an ID
'--------------------------------
Function Greet(C:TCPSocketConnection)
	C.MyID = "User [" + MilliSecs() + "]"
	C.MyServer.BroadCast("Welcome!~r~n",C)
	C.MyServer.BroadCast(C.MyID + " has entered the room.~r~n")	
End Function

'Alert other users when a user leaves
'------------------------------------
Function LostConnection(C:TCPSocketConnection)
	C.MyServer.BroadCast("~r~n" + C.MyID + " has left the room.~r~n~r~n")
End Function

'Create an Instance of the TCPSocketServer Class
'-------------------------------------------------
Global Server:TCPSocketServer = CreateTCPSocketServer()

'Assign Function Pointers to Server's callback handles
'-----------------------------------------------------
Server.MsgRcvdCallback = TextHandler
Server.NewConnectionCallback = Greet
Server.LostConnectionCallback = LostConnection

'The Main Loop
'--------------
While Not KeyHit(KEY_ESCAPE)
	Server.Listen()		'That's it!
Wend

Author Comments:

TCPSocketServer I thought Id throw my hat into the "TCPSocket Ring". This is an OOP approach to creating a TCPSocket server. Callbacks are used for extensibility. You can create functions to handle events and add whatever functionality you like. You can create many different servers listening to different ports, and assign different functionality to each server. The benefit of doing this is that each server is running withing the same process, and therefor causes less overhead drain on your system resources. The Event Callback handles are: NewConnectionCallback Triggered whenever a new client connects. The callback function takes one parameter of type TCPSocketConnection. Your callback function can access the various fields and methods of the connection. A link back to the connections server is also provided to give you access to the various fields and methods of the server. LostConnectionCallback Triggered whenever a client disconnects from the server. This callback also takes a TCPSocketConnection. After the server calls the callback function it removes the connection from its collection. MsgRcvdCallback Triggered whenever a client sends a message to the server. The callback function takes one parameter of type TCPSocketConnection. Your callback function can access the message in the connection objects "Buffer" field. The field is a string, but can easily be converted to an array of bytes for whatever processing you need to do. This function is where you would add any "Intelligence" to your server, ie, processing commands, etc. Methods Broadcast(Message:String, [conn:TCPSocketConnection = Null]) If a TCPSocketConnection is provided the server only broadcasts the message to that specific connection. Otherwise the server will broadcast the message to all of its connections. Listen() Updates the server connections and triggers events as they occure. TCPSocketConnections A TCPSocketConnection is the "pipeline" through which the server communicates with the clients that are connected. Each server object has its own collection of TCPSocketConnection objects. Methods Recieves messages from your program and tells the server to trigger the MsgRcvdCallback event. This works in a "Non-Blocking" fashion, so as not to hold up your application while waiting for input. Youre program causes the server to trigger this event by sending a "Stop Sequence". The server defaults this stop sequence to a Carriange Return/Line Feed {~r~n}. But you can change it to whatever you want by setting the servers "StopSeq" field.