文章正文：
用 Delphi 设计自己的代理服务器
file://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;
file://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;
file://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
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;
file://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;
file://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;