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分享求serversocket 阻塞 多线程 例子?
求serversocket 阻塞 多线程 例子?
是用于聊天程序,SOCKET以文本方式发送/接收.
多谢帮忙!
是用于聊天程序,SOCKET以文本方式发送/接收.
多谢帮忙!
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hammer_shi 2003-06-18
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if (session[i-1].CSocket.socket.sockethandle=socket.SocketHandle) and session[i-1].Used then
begin
session[i-1].CSocket.tag:=socket.SocketHandle;
session[i-1].remote_connected:=true; {置远程主机已连通标志}
session[i-1].Lookingup:=false; {清标志}
break;
end;
end;
//当远程主机断开时…
procedure TForm1.ClientSocket1Disconnect(Sender: TObject;
Socket: TCustomWinSocket);
var
i,j,k: integer;
begin
for i:=1 to sessions do
if (session[i-1].CSocket.tag=socket.SocketHandle) and session[i-1].Used then
begin
session[i-1].remote_connected:=false; {置为未连接}
if not session[i-1].client_connected then
session[i-1].Used:=false {假如客户机已断开，则置释放资源标志}
else
for k:=1 to serversocket1.Socket.ActiveConnections do
if (serversocket1.Socket.Connections[k-1].SocketHandle=session[i-1].SS_Handle) and session[i-1].used then
begin
serversocket1.Socket.Connections[k-1].Close;
break;
end;
break;
end;
j:=sessions;
k:=0;
for i:=1 to j do
begin
if session[j-i].Used then
break;
inc(k);
end;
if k>0 then {修正会话数组}
begin
sessions:=sessions-k;
setlength(session,sessions);
end;
edit1.text:=inttostr(sessions);
end;
//当与远程主机通信发生错误时…
procedure TForm1.ClientSocket1Error(Sender: TObject;
Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
var ErrorCode: Integer);
var
i,j,k: integer;
begin
for i:=1 to sessions do
if (session[i-1].CSocket.tag=socket.SocketHandle) and session[i-1].Used then
begin
socket.close;
session[i-1].remote_connected:=false; {置为未连接}
if not session[i-1].client_connected then
session[i-1].Used:=false {假如客户机已断开，则置释放资源标志}
else
for k:=1 to serversocket1.Socket.ActiveConnections do
if (serversocket1.Socket.Connections[k-1].SocketHandle=session[i-1].SS_Handle) and session[i-1].used then
begin
serversocket1.Socket.Connections[k-1].Close;
break;
end;
break;
end;
j:=sessions;
k:=0;
for i:=1 to j do
begin
if session[j-i].Used then
break;
inc(k);
end;
errorcode:=0;
if k>0 then {修正会话数组}
begin
sessions:=sessions-k;
setlength(session,sessions);
end;
edit1.text:=inttostr(sessions);
end;
//向远程主机发送页面请求…
procedure TForm1.ClientSocket1Write(Sender: TObject;
Socket: TCustomWinSocket);
var
i: integer;
begin
for i:=1 to sessions do
if (session[i-1].CSocket.tag=socket.SocketHandle) and session[i-1].Used then
begin
if session[i-1].Request then
begin
socket.SendText(session[i-1].request_str); {假如有请求，发送}
session[i-1].Request:=false; {清标志}
end;
break;
end;
end;
//远程主机发来页面数据时…
procedure TForm1.ClientSocket1Read(Sender: TObject;
Socket: TCustomWinSocket);
var
i,j: integer;
rec_bytes: integer; {传回的数据块长度}
rec_Buffer: array[0..2047] of char; {传回的数据块缓冲区}
begin
for i:=1 to sessions do
if (session[i-1].CSocket.tag=socket.SocketHandle) and session[i-1].Used then
begin
rec_bytes:=socket.ReceiveBuf(rec_buffer,2048); {接收数据}
for j:=1 to serversocket1.Socket.ActiveConnections do
if serversocket1.Socket.Connections[j-1].SocketHandle=session[i-1].SS_Handle then
begin
serversocket1.Socket.Connections[j-1].SendBuf(rec_buffer,rec_bytes); {发送数据}
break;
end;
break;
end;
end;
//“页面找不到”等错误信息出现时…
procedure TForm1.AppException(Sender: TObject; E: Exception);
begin
inc(invalidrequests);
end;
//查找远程主机定时…
procedure TForm1.Timer1Timer(Sender: TObject);
var
i,j: integer;
begin
for i:=1 to sessions do
if session[i-1].Used and session[i-1].Lookingup then {假如正在连接}
begin
inc(session[i-1].LookupTime);
if session[i-1].LookupTime>lookuptimeout then {假如超时}
begin
session[i-1].Lookingup:=false;
session[i-1].CSocket.active:=false; {停止查找}
for j:=1 to serversocket1.Socket.ActiveConnections do
if serversocket1.Socket.Connections[j-1].SocketHandle=session[i-1].SS_Handle then
begin
serversocket1.Socket.Connections[j-1].Close; {断开客户机}
break;
end;
end;
end;
end;
end.
hammer_shi 2003-06-18
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//被代理端连接到代理服务器后，建立一个会话，并与套接字绑定…
procedure TForm1.ServerSocket1ClientConnect(Sender: TObject;
Socket: TCustomWinSocket);
var
i,j: integer;
begin
j:=-1;
for i:=1 to sessions do {查找是否有空白项}
if not session[i-1].Used and not session[i-1].CSocket.active then
begin
j:=i-1; {有，分配它}
session[j].Used:=true; {置为在用}
break;
end
else
if not session[i-1].Used and session[i-1].CSocket.active then
session[i-1].CSocket.active:=false;
if j=-1 then
begin {无，新增一个}
j:=sessions;
inc(sessions);
setlength(session,sessions);
session[j].Used:=true; {置为在用}
session[j].CSocket:=TClientSocket.Create(nil);
session[j].CSocket.OnConnect:=ClientSocket1Connect;
session[j].CSocket.OnDisconnect:=ClientSocket1Disconnect;
session[j].CSocket.OnError:=ClientSocket1Error;
session[j].CSocket.OnRead:=ClientSocket1Read;
session[j].CSocket.OnWrite:=ClientSocket1Write;
session[j].Lookingup:=false;
end;
session[j].SS_Handle:=socket.socketHandle; {保存句柄，实现绑定}
session[j].Request:=false; {无请求}
session[j].client_connected:=true; {客户机已连接}
session[j].remote_connected:=false; {远程未连接}
edit1.text:=inttostr(sessions);
end;
//被代理端断开时…
procedure TForm1.ServerSocket1ClientDisconnect(Sender: TObject;
Socket: TCustomWinSocket);
var
i,j,k: integer;
begin
for i:=1 to sessions do
if (session[i-1].SS_Handle=socket.SocketHandle) and session[i-1].Used then
begin
session[i-1].client_connected:=false; {客户机未连接}
if session[i-1].remote_connected then
session[i-1].CSocket.active:=false {假如远程尚连接，断开它}
else
session[i-1].Used:=false; {假如两者都断开，则置释放资源标志}
break;
end;
j:=sessions;
k:=0;
for i:=1 to j do {统计会话数组尾部有几个未用项}
begin
if session[j-i].Used then
break;
inc(k);
end;
if k>0 then {修正会话数组，释放尾部未用项}
begin
sessions:=sessions-k;
setlength(session,sessions);
end;
edit1.text:=inttostr(sessions);
end;
//通信错误出现时…
procedure TForm1.ServerSocket1ClientError(Sender: TObject;
Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
var ErrorCode: Integer);
var
i,j,k: integer;
begin
for i:=1 to sessions do
if (session[i-1].SS_Handle=socket.SocketHandle) and session[i-1].Used then
begin
session[i-1].client_connected:=false; {客户机未连接}
if session[i-1].remote_connected then
session[i-1].CSocket.active:=false {假如远程尚连接，断开它}
else
session[i-1].Used:=false; {假如两者都断开，则置释放资源标志}
break;
end;
j:=sessions;
k:=0;
for i:=1 to j do
begin
if session[j-i].Used then
break;
inc(k);
end;
if k>0 then
begin
sessions:=sessions-k;
setlength(session,sessions);
end;
edit1.text:=inttostr(sessions);
errorcode:=0;
end;
//被代理端发送来页面请求时…
procedure TForm1.ServerSocket1ClientRead(Sender: TObject;
Socket: TCustomWinSocket);
var
tmp,line,host: string;
i,j,port: integer;
begin
for i:=1 to sessions do {判断是哪一个会话}
if session[i-1].Used and (session[i-1].SS_Handle=socket.sockethandle) then
begin
session[i-1].request_str:=socket.ReceiveText; {保存请求数据}
tmp:=session[i-1].request_str; {存放到临时变量}
memo1.lines.add(tmp);
j:=pos(char(13)+char(10),tmp); {一行标志}
while j>0 do {逐行扫描请求文本，查找主机地址}
begin
line:=copy(tmp,1,j-1); {取一行}
delete(tmp,1,j+1); {删除一行}
j:=pos('Host',line); {主机地址标志}
if j>0 then
begin
delete(line,1,j+5); {删除前面的无效字符}
j:=pos(':',line);
if j>0 then
begin
host:=copy(line,1,j-1);
delete(line,1,j);
try
port:=strtoint(line);
except
port:=80;
end;
end
else
begin
host:=trim(line); {获取主机地址}
port:=80;
end;
if not session[i-1].remote_connected then {假如远征尚未连接}
begin
session[i-1].Request:=true; {置请求数据就绪标志}
session[i-1].CSocket.host:=host; {设置远程主机地址}
session[i-1].CSocket.port:=port; {设置端口}
session[i-1].CSocket.active:=true; {连接远程主机}
session[i-1].Lookingup:=true; {置标志}
session[i-1].LookupTime:=0; {从0开始计时}
end
else
{假如远程已连接，直接发送请求}
session[i-1].CSocket.socket.sendtext(session[i-1].request_str);
break; {停止扫描请求文本}
end;
j:=pos(char(13)+char(10),tmp); {指向下一行}
end;
break; {停止循环}
end;
end;
//当连接远程主机成功时…
procedure TForm1.ClientSocket1Connect(Sender: TObject;
Socket: TCustomWinSocket);
var
i: integer;
begin
for i:=1 to sessions do
procedure TForm1.ServerSocket1ClientConnect(Sender: TObject;
Socket: TCustomWinSocket);
var
i,j: integer;
begin
j:=-1;
for i:=1 to sessions do {查找是否有空白项}
if not session[i-1].Used and not session[i-1].CSocket.active then
begin
j:=i-1; {有，分配它}
session[j].Used:=true; {置为在用}
break;
end
else
if not session[i-1].Used and session[i-1].CSocket.active then
session[i-1].CSocket.active:=false;
if j=-1 then
begin {无，新增一个}
j:=sessions;
inc(sessions);
setlength(session,sessions);
session[j].Used:=true; {置为在用}
session[j].CSocket:=TClientSocket.Create(nil);
session[j].CSocket.OnConnect:=ClientSocket1Connect;
session[j].CSocket.OnDisconnect:=ClientSocket1Disconnect;
session[j].CSocket.OnError:=ClientSocket1Error;
session[j].CSocket.OnRead:=ClientSocket1Read;
session[j].CSocket.OnWrite:=ClientSocket1Write;
session[j].Lookingup:=false;
end;
session[j].SS_Handle:=socket.socketHandle; {保存句柄，实现绑定}
session[j].Request:=false; {无请求}
session[j].client_connected:=true; {客户机已连接}
session[j].remote_connected:=false; {远程未连接}
edit1.text:=inttostr(sessions);
end;
//被代理端断开时…
procedure TForm1.ServerSocket1ClientDisconnect(Sender: TObject;
Socket: TCustomWinSocket);
var
i,j,k: integer;
begin
for i:=1 to sessions do
if (session[i-1].SS_Handle=socket.SocketHandle) and session[i-1].Used then
begin
session[i-1].client_connected:=false; {客户机未连接}
if session[i-1].remote_connected then
session[i-1].CSocket.active:=false {假如远程尚连接，断开它}
else
session[i-1].Used:=false; {假如两者都断开，则置释放资源标志}
break;
end;
j:=sessions;
k:=0;
for i:=1 to j do {统计会话数组尾部有几个未用项}
begin
if session[j-i].Used then
break;
inc(k);
end;
if k>0 then {修正会话数组，释放尾部未用项}
begin
sessions:=sessions-k;
setlength(session,sessions);
end;
edit1.text:=inttostr(sessions);
end;
//通信错误出现时…
procedure TForm1.ServerSocket1ClientError(Sender: TObject;
Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
var ErrorCode: Integer);
var
i,j,k: integer;
begin
for i:=1 to sessions do
if (session[i-1].SS_Handle=socket.SocketHandle) and session[i-1].Used then
begin
session[i-1].client_connected:=false; {客户机未连接}
if session[i-1].remote_connected then
session[i-1].CSocket.active:=false {假如远程尚连接，断开它}
else
session[i-1].Used:=false; {假如两者都断开，则置释放资源标志}
break;
end;
j:=sessions;
k:=0;
for i:=1 to j do
begin
if session[j-i].Used then
break;
inc(k);
end;
if k>0 then
begin
sessions:=sessions-k;
setlength(session,sessions);
end;
edit1.text:=inttostr(sessions);
errorcode:=0;
end;
//被代理端发送来页面请求时…
procedure TForm1.ServerSocket1ClientRead(Sender: TObject;
Socket: TCustomWinSocket);
var
tmp,line,host: string;
i,j,port: integer;
begin
for i:=1 to sessions do {判断是哪一个会话}
if session[i-1].Used and (session[i-1].SS_Handle=socket.sockethandle) then
begin
session[i-1].request_str:=socket.ReceiveText; {保存请求数据}
tmp:=session[i-1].request_str; {存放到临时变量}
memo1.lines.add(tmp);
j:=pos(char(13)+char(10),tmp); {一行标志}
while j>0 do {逐行扫描请求文本，查找主机地址}
begin
line:=copy(tmp,1,j-1); {取一行}
delete(tmp,1,j+1); {删除一行}
j:=pos('Host',line); {主机地址标志}
if j>0 then
begin
delete(line,1,j+5); {删除前面的无效字符}
j:=pos(':',line);
if j>0 then
begin
host:=copy(line,1,j-1);
delete(line,1,j);
try
port:=strtoint(line);
except
port:=80;
end;
end
else
begin
host:=trim(line); {获取主机地址}
port:=80;
end;
if not session[i-1].remote_connected then {假如远征尚未连接}
begin
session[i-1].Request:=true; {置请求数据就绪标志}
session[i-1].CSocket.host:=host; {设置远程主机地址}
session[i-1].CSocket.port:=port; {设置端口}
session[i-1].CSocket.active:=true; {连接远程主机}
session[i-1].Lookingup:=true; {置标志}
session[i-1].LookupTime:=0; {从0开始计时}
end
else
{假如远程已连接，直接发送请求}
session[i-1].CSocket.socket.sendtext(session[i-1].request_str);
break; {停止扫描请求文本}
end;
j:=pos(char(13)+char(10),tmp); {指向下一行}
end;
break; {停止循环}
end;
end;
//当连接远程主机成功时…
procedure TForm1.ClientSocket1Connect(Sender: TObject;
Socket: TCustomWinSocket);
var
i: integer;
begin
for i:=1 to sessions do
hammer_shi 2003-06-18
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post
用Delphi设计自己的代理服务器
笔者在编写一个上网计费软件时，涉及到如何对局域网中各工作站上网计费问题。一般来讲，这些工作站通过代理服务器上网，而采用现成的代理服务器软件时，由于代理服务器软件是封闭的系统，很难编写程序获取实时的上网计时信息。因此，考虑是否能编写自己的代理服务器，一方面解决群体上网，另一方面又解决上网的计费问题呢？
经过实验性编程，终于圆满地解决了该问题。现写出来，与各位同行分享。
思路
当前流行的浏览器的系统选项中有一个参数，即“通过代理服务器连接”，经过编程测
试，当局域网中一台工作站指定了该属性，再发出Internet请求时，请求数据将发送到所指定的代理服务器上，以下为请求数据包示例：
GET http://home.microsoft.com/intl/cn/ HTTP/1.0
Accept: */*
Accept-Language: zh-cn
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.0; Windows NT)
Host: home.microsoft.com
Proxy-Connection: Keep-Alive
其中第一行为目标URL及相关方法、协议，“Host”行指定了目标主机的地址。
由此知道了代理服务的过程：接收被代理端的请求、连接真正的主机、接收主机返回的数据、将接收数据发送到被代理端。
为此可编写一个简单的程序，完成上述网络通信重定向问题。
用Delphi设计时，选用ServerSocket作为与被代理工作站通信的套接字控件，选用ClientSocket动态数组作为与远程主机通信的套接字控件。
编程时应解决的一个重要问题是多重连接处理问题，为了加快代理服务的速度和被代理端的响应速度，套接字控件的属性应设为非阻塞型；各通信会话与套接字动态绑定，用套接字的SocketHandle属性值确定属于哪一个会话。
通信的衔接过程如下图所示：
代理服务器
Serversocket
(1) 接 收
被代理端 发 送 远程主机
(6) (2) (5)
Browser ClientSocket (4) Web Server
接 收
发 送 (3)
（1）、被代理端浏览器发出Web请求，代理服务器的Serversocket接收到请求。
（2）、代理服务器程序自动创建一个ClientSocket，并设置主机地址、端口等属性，然后连接远程主机。
（3）、远程连通后激发发送事件，将Serversocket接收到的Web请求数据包发送到远程主机。
（4）、当远程主机返回页面数据时，激发ClientSocket的读事件，读取页面数据。
（5）、代理服务器程序根据绑定信息确定属于ServerSocket控件中的哪一个Socket应该将从主机接收的页面信息发送到被代理端。
（6）、ServerSocket中的对应Socket将页面数据发送到被代理端。
程序编写
使用Delphi设计以上通信过程非常简单，主要是ServerSocket、ClientSocket的相关事
件驱动程序的程序编写。下面给出作者编写的实验用代理服务器界面与源程序清单，内含简要功能说明：
unit main;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ExtCtrls, ScktComp, TrayIcon, Menus, StdCtrls;
type
session_record=record
Used: boolean; {会话记录是否可用}
SS_Handle: integer; {代理服务器套接字句柄}
CSocket: TClientSocket; {用于连接远程的套接字}
Lookingup: boolean; {是否正在查找服务器}
LookupTime: integer; {查找服务器时间}
Request: boolean; {是否有请求}
request_str: string; {请求数据块}
client_connected: boolean; {客户机联机标志}
remote_connected: boolean; {远程服务器连接标志}
end;
type
TForm1 = class(TForm)
ServerSocket1: TServerSocket;
ClientSocket1: TClientSocket;
Timer2: TTimer;
TrayIcon1: TTrayIcon;
PopupMenu1: TPopupMenu;
N11: TMenuItem;
N21: TMenuItem;
N1: TMenuItem;
N01: TMenuItem;
Memo1: TMemo;
Edit1: TEdit;
Label1: TLabel;
Timer1: TTimer;
procedure Timer2Timer(Sender: TObject);
procedure N11Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure N21Click(Sender: TObject);
procedure N01Click(Sender: TObject);
procedure ServerSocket1ClientConnect(Sender: TObject;
Socket: TCustomWinSocket);
procedure ServerSocket1ClientDisconnect(Sender: TObject;
Socket: TCustomWinSocket);
procedure ServerSocket1ClientError(Sender: TObject;
Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
var ErrorCode: Integer);
procedure ServerSocket1ClientRead(Sender: TObject;
Socket: TCustomWinSocket);
procedure ClientSocket1Connect(Sender: TObject;
Socket: TCustomWinSocket);
procedure ClientSocket1Disconnect(Sender: TObject;
Socket: TCustomWinSocket);
procedure ClientSocket1Error(Sender: TObject; Socket: TCustomWinSocket;
ErrorEvent: TErrorEvent; var ErrorCode: Integer);
procedure ClientSocket1Write(Sender: TObject;
Socket: TCustomWinSocket);
procedure ClientSocket1Read(Sender: TObject; Socket: TCustomWinSocket);
procedure ServerSocket1Listen(Sender: TObject;
Socket: TCustomWinSocket);
procedure AppException(Sender: TObject; E: Exception);
procedure Timer1Timer(Sender: TObject);
private
{ Private declarations }
public
Service_Enabled: boolean; {代理服务是否开启}
session: array of session_record; {会话数组}
sessions: integer; {会话数}
LookUpTimeOut: integer; {连接超时值}
InvalidRequests: integer; {无效请求数}
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
//系统启动定时器，启动窗显示完成后，缩小到System Tray…
procedure TForm1.Timer2Timer(Sender: TObject);
begin
timer2.Enabled:=false; {关闭定时器}
sessions:=0; {会话数=0}
Application.OnException := AppException; {为了屏蔽代理服务器出现的异常}
invalidRequests:=0; {0错误}
LookUpTimeOut:=60000; {超时值=1分钟}
timer1.Enabled:=true; {打开定时器}
n11.Enabled:=false; {开启服务菜单项失效}
n21.Enabled:=true; {关闭服务菜单项有效}
serversocket1.Port:=988; {代理服务器端口=988}
serversocket1.Active:=true; {开启服务}
form1.hide; {隐藏界面，缩小到System Tray上}
end;
//开启服务菜单项…
procedure TForm1.N11Click(Sender: TObject);
begin
serversocket1.Active:=true; {开启服务}
end;
//停止服务菜单项…
procedure TForm1.N21Click(Sender: TObject);
begin
serversocket1.Active:=false; {停止服务}
N11.Enabled:=True;
N21.Enabled:=False;
Service_Enabled:=false; {标志清零}
end;
//主窗口建立…
procedure TForm1.FormCreate(Sender: TObject);
begin
Service_Enabled:=false;
timer2.Enabled:=true; {窗口建立时，打开定时器}
end;
//窗口关闭时…
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
timer1.Enabled:=false; {关闭定时器}
if Service_Enabled then
serversocket1.Active:=false; {退出程序时关闭服务}
end;
//退出程序按钮…
procedure TForm1.N01Click(Sender: TObject);
begin
form1.Close; {退出程序}
end;
//开启代理服务后…
procedure TForm1.ServerSocket1Listen(Sender: TObject;
Socket: TCustomWinSocket);
begin
Service_Enabled:=true; {置正在服务标志}
N11.Enabled:=false;
N21.Enabled:=true;
end;
用Delphi设计自己的代理服务器
笔者在编写一个上网计费软件时，涉及到如何对局域网中各工作站上网计费问题。一般来讲，这些工作站通过代理服务器上网，而采用现成的代理服务器软件时，由于代理服务器软件是封闭的系统，很难编写程序获取实时的上网计时信息。因此，考虑是否能编写自己的代理服务器，一方面解决群体上网，另一方面又解决上网的计费问题呢？
经过实验性编程，终于圆满地解决了该问题。现写出来，与各位同行分享。
思路
当前流行的浏览器的系统选项中有一个参数，即“通过代理服务器连接”，经过编程测
试，当局域网中一台工作站指定了该属性，再发出Internet请求时，请求数据将发送到所指定的代理服务器上，以下为请求数据包示例：
GET http://home.microsoft.com/intl/cn/ HTTP/1.0
Accept: */*
Accept-Language: zh-cn
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 5.0; Windows NT)
Host: home.microsoft.com
Proxy-Connection: Keep-Alive
其中第一行为目标URL及相关方法、协议，“Host”行指定了目标主机的地址。
由此知道了代理服务的过程：接收被代理端的请求、连接真正的主机、接收主机返回的数据、将接收数据发送到被代理端。
为此可编写一个简单的程序，完成上述网络通信重定向问题。
用Delphi设计时，选用ServerSocket作为与被代理工作站通信的套接字控件，选用ClientSocket动态数组作为与远程主机通信的套接字控件。
编程时应解决的一个重要问题是多重连接处理问题，为了加快代理服务的速度和被代理端的响应速度，套接字控件的属性应设为非阻塞型；各通信会话与套接字动态绑定，用套接字的SocketHandle属性值确定属于哪一个会话。
通信的衔接过程如下图所示：
代理服务器
Serversocket
(1) 接 收
被代理端 发 送 远程主机
(6) (2) (5)
Browser ClientSocket (4) Web Server
接 收
发 送 (3)
（1）、被代理端浏览器发出Web请求，代理服务器的Serversocket接收到请求。
（2）、代理服务器程序自动创建一个ClientSocket，并设置主机地址、端口等属性，然后连接远程主机。
（3）、远程连通后激发发送事件，将Serversocket接收到的Web请求数据包发送到远程主机。
（4）、当远程主机返回页面数据时，激发ClientSocket的读事件，读取页面数据。
（5）、代理服务器程序根据绑定信息确定属于ServerSocket控件中的哪一个Socket应该将从主机接收的页面信息发送到被代理端。
（6）、ServerSocket中的对应Socket将页面数据发送到被代理端。
程序编写
使用Delphi设计以上通信过程非常简单，主要是ServerSocket、ClientSocket的相关事
件驱动程序的程序编写。下面给出作者编写的实验用代理服务器界面与源程序清单，内含简要功能说明：
unit main;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ExtCtrls, ScktComp, TrayIcon, Menus, StdCtrls;
type
session_record=record
Used: boolean; {会话记录是否可用}
SS_Handle: integer; {代理服务器套接字句柄}
CSocket: TClientSocket; {用于连接远程的套接字}
Lookingup: boolean; {是否正在查找服务器}
LookupTime: integer; {查找服务器时间}
Request: boolean; {是否有请求}
request_str: string; {请求数据块}
client_connected: boolean; {客户机联机标志}
remote_connected: boolean; {远程服务器连接标志}
end;
type
TForm1 = class(TForm)
ServerSocket1: TServerSocket;
ClientSocket1: TClientSocket;
Timer2: TTimer;
TrayIcon1: TTrayIcon;
PopupMenu1: TPopupMenu;
N11: TMenuItem;
N21: TMenuItem;
N1: TMenuItem;
N01: TMenuItem;
Memo1: TMemo;
Edit1: TEdit;
Label1: TLabel;
Timer1: TTimer;
procedure Timer2Timer(Sender: TObject);
procedure N11Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure N21Click(Sender: TObject);
procedure N01Click(Sender: TObject);
procedure ServerSocket1ClientConnect(Sender: TObject;
Socket: TCustomWinSocket);
procedure ServerSocket1ClientDisconnect(Sender: TObject;
Socket: TCustomWinSocket);
procedure ServerSocket1ClientError(Sender: TObject;
Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
var ErrorCode: Integer);
procedure ServerSocket1ClientRead(Sender: TObject;
Socket: TCustomWinSocket);
procedure ClientSocket1Connect(Sender: TObject;
Socket: TCustomWinSocket);
procedure ClientSocket1Disconnect(Sender: TObject;
Socket: TCustomWinSocket);
procedure ClientSocket1Error(Sender: TObject; Socket: TCustomWinSocket;
ErrorEvent: TErrorEvent; var ErrorCode: Integer);
procedure ClientSocket1Write(Sender: TObject;
Socket: TCustomWinSocket);
procedure ClientSocket1Read(Sender: TObject; Socket: TCustomWinSocket);
procedure ServerSocket1Listen(Sender: TObject;
Socket: TCustomWinSocket);
procedure AppException(Sender: TObject; E: Exception);
procedure Timer1Timer(Sender: TObject);
private
{ Private declarations }
public
Service_Enabled: boolean; {代理服务是否开启}
session: array of session_record; {会话数组}
sessions: integer; {会话数}
LookUpTimeOut: integer; {连接超时值}
InvalidRequests: integer; {无效请求数}
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
//系统启动定时器，启动窗显示完成后，缩小到System Tray…
procedure TForm1.Timer2Timer(Sender: TObject);
begin
timer2.Enabled:=false; {关闭定时器}
sessions:=0; {会话数=0}
Application.OnException := AppException; {为了屏蔽代理服务器出现的异常}
invalidRequests:=0; {0错误}
LookUpTimeOut:=60000; {超时值=1分钟}
timer1.Enabled:=true; {打开定时器}
n11.Enabled:=false; {开启服务菜单项失效}
n21.Enabled:=true; {关闭服务菜单项有效}
serversocket1.Port:=988; {代理服务器端口=988}
serversocket1.Active:=true; {开启服务}
form1.hide; {隐藏界面，缩小到System Tray上}
end;
//开启服务菜单项…
procedure TForm1.N11Click(Sender: TObject);
begin
serversocket1.Active:=true; {开启服务}
end;
//停止服务菜单项…
procedure TForm1.N21Click(Sender: TObject);
begin
serversocket1.Active:=false; {停止服务}
N11.Enabled:=True;
N21.Enabled:=False;
Service_Enabled:=false; {标志清零}
end;
//主窗口建立…
procedure TForm1.FormCreate(Sender: TObject);
begin
Service_Enabled:=false;
timer2.Enabled:=true; {窗口建立时，打开定时器}
end;
//窗口关闭时…
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
timer1.Enabled:=false; {关闭定时器}
if Service_Enabled then
serversocket1.Active:=false; {退出程序时关闭服务}
end;
//退出程序按钮…
procedure TForm1.N01Click(Sender: TObject);
begin
form1.Close; {退出程序}
end;
//开启代理服务后…
procedure TForm1.ServerSocket1Listen(Sender: TObject;
Socket: TCustomWinSocket);
begin
Service_Enabled:=true; {置正在服务标志}
N11.Enabled:=false;
N21.Enabled:=true;
end;
