Select模型的简单实现

最新推荐文章于 2022-09-29 23:07:34 发布

jlutt

最新推荐文章于 2022-09-29 23:07:34 发布

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分类专栏： Delphi 文章标签： integer button socket initialization stream string

本文链接：https://blog.youkuaiyun.com/jlutt/article/details/611329

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本文介绍了一个基于Delphi的TCP服务器实现案例，利用IO多路复用技术（select模型）来处理多个客户端连接。文章详细展示了如何创建监听套接字、接收客户端连接请求、并处理客户端发送的数据。

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interface

uses

Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,

Winsock2, StdCtrls;

type

TfrmMain = class(TForm)

Button1: TButton;

Button2: TButton;

procedure Button1Click(Sender: TObject);

procedure Button2Click(Sender: TObject);

private

{ Private declarations }

public

{ Public declarations }

procedure IOSelectMain;

end;

var

frmMain: TfrmMain;

WSData: TWSAData;

implementation

{$R *.DFM}

{ TfrmMain }

procedure CopyFDSet(Source: TFDSet; var Dest: TFDSet);

var

i: Integer;

begin

FD_ZERO(Dest);

for i:=0 to Source.fd_count - 1 do begin

FD_SET(Source.fd_array[i], Dest);

end;

procedure TfrmMain.IOSelectMain;

var

sListen, sNew: TSocket;

sin, addrRemote: TSockAddrIn;

fdSocket, fdRead: TFDSet;

nRet, nAddrLen, nRecv: Integer;

i: Integer;

sRecv: string;

begin

//创建监听套接字

sListen := socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

sin.sin_family := AF_INET;

sin.sin_port := htons(4567);

sin.sin_addr.S_addr := INADDR_ANY;

//绑定套接字到本机

if bind(sListen, @sin, SizeOf(sin)) = SOCKET_ERROR then exit;

//进入监听模式

listen(sListen, 5);

//select模型处理过程

//1.初始化一个套接字集合fdSocket, 添加监听套接字句柄到这个集合

FD_ZERO(fdSocket);

FD_SET(sListen, fdSocket);

while true do begin

//2.将fdSocket集合的一个拷贝fdRead传递给select函数

// 当有事件发生时，select函数移除fdRead集合中没有

//未决I/O操作的套接字句柄，然后返回

CopyFDSet(fdSocket, fdRead);

nRet := select(0, @fdRead, nil, nil, nil);

if (nRet>0) then begin

//3.通过将原来fdSocket集合与select处理过的fdRead集合比较

//确定有哪些套接字有未决I/O

for i:=0 to fdSocket.fd_count-1 do begin

if (FD_ISSET(fdSocket.fd_array[i], fdRead)) then begin

if (fdSocket.fd_array[i]=sListen) then begin

//监听套接字接收到新连接

if (fdSocket.fd_count < FD_SETSIZE) then begin

nAddrLen := sizeOf(addrRemote);

sNew := accept(sListen, addrRemote, nAddrLen);

FD_SET(sNew, fdSocket);

ShowMessage(inet_ntoa(addrRemote.sin_addr));

end else begin

Continue;

end;

end else begin

SetLength(sRecv, 1024);

nRecv := recv(fdSocket.fd_array[i], sRecv[1], 1024, 0);

if (nRecv>0) then begin

SetLength(sRecv, nRecv);

ShowMessage(sRecv);

end else begin

closesocket(fdSocket.fd_array[i]);

FD_CLR(fdSocket.fd_array[i], fdSocket);

ShowMessage(' Client Quit');

end;

end else begin

end;

end else exit;

end;

procedure TfrmMain.Button1Click(Sender: TObject);

begin

IOSelectMain;

end;

procedure TfrmMain.Button2Click(Sender: TObject);

var

clientSocket: TSocket;

servAddr: TSockAddrIn;

sendstr: string;

begin

clientSocket := socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

try

if clientSocket = INVALID_SOCKET then exit;

servAddr.sin_family := AF_INET;

servAddr.sin_port := htons(4567);

servAddr.sin_addr.S_addr := inet_addr('127.0.0.1');

if connect(clientSocket, @servAddr, SizeOf(servAddr)) = -1 then exit;

sendstr := 'test';

send(clientSocket, Pointer(sendstr)^, Length(sendstr), 0);

finally

CloseSocket(clientSocket);

end;

initialization

WSAStartup($0202, WSData);

finalization

WSACleanup;

end.