<br>用Delphi設(shè)計(jì)自己的代理服務(wù)器
<br>
<br> �牴P者在編寫(xiě)一個(gè)上網(wǎng)計(jì)費(fèi)軟件時(shí)，涉及到如何對(duì)局域網(wǎng)中各工作站上網(wǎng)計(jì)費(fèi)問(wèn)題。一般來(lái)講，這些工作站通過(guò)代理服務(wù)器上網(wǎng)，而采用現(xiàn)成的代理服務(wù)器軟件時(shí)，由于代理服務(wù)器軟件是封閉的系統(tǒng)，很難編寫(xiě)程序獲取實(shí)時(shí)的上網(wǎng)計(jì)時(shí)信息。因此，考慮是否能編寫(xiě)自己的代理服務(wù)器，一方面解決群體上網(wǎng)，另一方面又解決上網(wǎng)的計(jì)費(fèi)問(wèn)題呢？
<br> �牻�(jīng)過(guò)實(shí)驗(yàn)性編程，終于圓滿地解決了該問(wèn)題。現(xiàn)寫(xiě)出來(lái)，與各位同行分享。
<br>
<br>1、思路
<br>當(dāng)前流行的瀏覽器的系統(tǒng)選項(xiàng)中有一個(gè)參數(shù)，即“通過(guò)代理服務(wù)器連接”，經(jīng)過(guò)編程測(cè)
<br>試，當(dāng)局域網(wǎng)中一臺(tái)工作站指定了該屬性，再發(fā)出Internet請(qǐng)求時(shí)，請(qǐng)求數(shù)據(jù)將發(fā)送到所指定的代理服務(wù)器上，以下為請(qǐng)求數(shù)據(jù)包示例：
<br> �牐牐牐牐牐牐牐燝EThttp://home.microsoft.com/intl/cn/HTTP/1.0
<br> �牐牐牐牐牐牐牐燗ccept:*/*
<br> �牐牐牐牐牐牐牐燗ccept-Language:zh-cn
<br> �牐牐牐牐牐牐牐燗ccept-Encoding:gzip,deflate
<br> �牐牐牐牐牐牐牐燯ser-Agent:Mozilla/4.0(compatible;MSIE5.0;WindowsNT)
<br> �牐牐牐牐牐牐牐燞ost:home.microsoft.com
<br> �牐牐牐牐牐牐牐燩roxy-Connection:Keep-Alive
<br>其中第一行為目標(biāo)URL及相關(guān)方法、協(xié)議，“Host”行指定了目標(biāo)主機(jī)的地址。
<br>由此知道了代理服務(wù)的過(guò)程：接收被代理端的請(qǐng)求、連接真正的主機(jī)、接收主機(jī)返回的數(shù)據(jù)、將接收數(shù)據(jù)發(fā)送到被代理端。
<br>為此可編寫(xiě)一個(gè)簡(jiǎn)單的程序，完成上述網(wǎng)絡(luò)通信重定向問(wèn)題。
<br>用Delphi設(shè)計(jì)時(shí)，選用ServerSocket作為與被代理工作站通信的套接字控件，選用ClientSocket動(dòng)態(tài)數(shù)組作為與遠(yuǎn)程主機(jī)通信的套接字控件。
<br>編程時(shí)應(yīng)解決的一個(gè)重要問(wèn)題是多重連接處理問(wèn)題，為了加快代理服務(wù)的速度和被代理端的響應(yīng)速度，套接字控件的屬性應(yīng)設(shè)為非阻塞型；各通信會(huì)話與套接字動(dòng)態(tài)綁定，用套接字的SocketHandle屬性值確定屬于哪一個(gè)會(huì)話。
<br>通信的銜接過(guò)程如下圖所示：
<br>
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐牐牬�理服務(wù)器
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐牐�
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐牐燬erversocket
<br> �牐牐牐牐牐牐牐牐牐牐�(1)�牐牐牐牐牻樱犑�
<br> �牐牐牐牨淮�理端�牐牐牐牐牐牐牐牐牥l(fā)�犓停牐牐牐牐牐牐牐牐牐牐牐犨h(yuǎn)程主機(jī)
<br> �牐牐牐牐牐牐牐牐牐牐�(6)�牐牐牐�(2)�牐牐�(5)
<br> �牐牐牐燘rowser�牐牐牐牐牐牐牐牐燙lientSocket�牐牐�(4)�牐牐牐牐牐燱ebServer
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐牐牐牻樱犑�
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐牐牐牥l(fā)�犓停牐牐牐牐�(3)
<br>
<br>
<br>（1）、被代理端瀏覽器發(fā)出Web請(qǐng)求，代理服務(wù)器的Serversocket接收到請(qǐng)求。
<br>（2）、代理服務(wù)器程序自動(dòng)創(chuàng)建一個(gè)ClientSocket，并設(shè)置主機(jī)地址、端口等屬性，然后連接遠(yuǎn)程主機(jī)。
<br>（3）、遠(yuǎn)程連通后激發(fā)發(fā)送事件，將Serversocket接收到的Web請(qǐng)求數(shù)據(jù)包發(fā)送到遠(yuǎn)程主機(jī)。
<br>（4）、當(dāng)遠(yuǎn)程主機(jī)返回頁(yè)面數(shù)據(jù)時(shí)，激發(fā)ClientSocket的讀事件，讀取頁(yè)面數(shù)據(jù)。
<br>（5）、代理服務(wù)器程序根據(jù)綁定信息確定屬于ServerSocket控件中的哪一個(gè)Socket應(yīng)該將從主機(jī)接收的頁(yè)面信息發(fā)送到被代理端。
<br>（6）、ServerSocket中的對(duì)應(yīng)Socket將頁(yè)面數(shù)據(jù)發(fā)送到被代理端。
<br>
<br>2、程序編寫(xiě)
<br>使用Delphi設(shè)計(jì)以上通信過(guò)程非常簡(jiǎn)單，主要是ServerSocket、ClientSocket的相關(guān)事
<br>件驅(qū)動(dòng)程序的程序編寫(xiě)。下面給出作者編寫(xiě)的實(shí)驗(yàn)用代理服務(wù)器界面與源程序清單，內(nèi)含簡(jiǎn)要功能說(shuō)明：
<br>
<br>unitmain;
<br>
<br>interface
<br>
<br>uses
<br> Windows,Messages,SysUtils,Classes,Graphics,Controls,Forms,Dialogs,
<br> ExtCtrls,ScktComp,TrayIcon,Menus,StdCtrls;
<br>
<br>type
<br> �爏ession_record=record
<br> �牐燯sed:boolean;�牐牐牐牐牐牐牐牐牐牐�
<br> �牐燬S_Handle:integer;�牐牐牐牐牐牐牐牐�
<br> �牐燙Socket:TClientSocket;�牐牐牐牐牐牐�
<br> �牐燣ookingup:boolean;�牐牐牐牐牐牐牐牐�
<br> �牐燣ookupTime:integer;�牐牐牐牐牐牐牐�
<br> �牐燫equest:boolean;�牐牐牐牐牐牐牐牐牐�
<br> �牐爎equest_str:string;�牐牐牐牐牐牐牐�
<br> �牐燾lient_connected:boolean;�牐牐牐牐�
<br> �牐爎emote_connected:boolean;�牐牐牐牐�
<br>end;
<br>
<br>type
<br> TForm1=class(TForm)
<br> �燬erverSocket1:TServerSocket;
<br> �燙lientSocket1:TClientSocket;
<br> �燭imer2:TTimer;
<br> �燭rayIcon1:TTrayIcon;
<br> �燩opupMenu1:TPopupMenu;
<br> �燦11:TMenuItem;
<br> �燦21:TMenuItem;
<br> �燦1:TMenuItem;
<br> �燦01:TMenuItem;
<br> �燤emo1:TMemo;
<br> �燛dit1:TEdit;
<br> �燣abel1:TLabel;
<br> �燭imer1:TTimer;
<br> �爌rocedureTimer2Timer(Sender:TObject);
<br> �爌rocedureN11Click(Sender:TObject);
<br> �爌rocedureFormCreate(Sender:TObject);
<br> �爌rocedureFormClose(Sender:TObject;varAction:TCloseAction);
<br> �爌rocedureN21Click(Sender:TObject);
<br> �爌rocedureN01Click(Sender:TObject);
<br> �爌rocedureServerSocket1ClientConnect(Sender:TObject;
<br> �牐燬ocket:TCustomWinSocket);
<br> �爌rocedureServerSocket1ClientDisconnect(Sender:TObject;
<br> �牐燬ocket:TCustomWinSocket);
<br> �爌rocedureServerSocket1ClientError(Sender:TObject;
<br> �牐燬ocket:TCustomWinSocket;ErrorEvent:TErrorEvent;
<br> �牐爒arErrorCode:Integer);
<br> �爌rocedureServerSocket1ClientRead(Sender:TObject;
<br> �牐燬ocket:TCustomWinSocket);
<br> �爌rocedureClientSocket1Connect(Sender:TObject;
<br> �牐燬ocket:TCustomWinSocket);
<br> �爌rocedureClientSocket1Disconnect(Sender:TObject;
<br> �牐燬ocket:TCustomWinSocket);
<br> �爌rocedureClientSocket1Error(Sender:TObject;Socket:TCustomWinSocket;
<br> �牐燛rrorEvent:TErrorEvent;varErrorCode:Integer);
<br> �爌rocedureClientSocket1Write(Sender:TObject;
<br> �牐燬ocket:TCustomWinSocket);
<br> �爌rocedureClientSocket1Read(Sender:TObject;Socket:TCustomWinSocket);
<br> �爌rocedureServerSocket1Listen(Sender:TObject;
<br> �牐燬ocket:TCustomWinSocket);
<br> �爌rocedureAppException(Sender:TObject;E:Exception);
<br> �爌rocedureTimer1Timer(Sender:TObject);
<br> **
<br> �爗**declarations}
<br> public
<br> �燬ervice_Enabled:boolean;�牐牐牐牐�
<br> �爏ession:arrayofsession_record;�牐牐�
<br> �爏essions:integer;�牐牐牐牐牐牐牐牐�
<br> �燣ookUpTimeOut:integer;�牐牐牐牐�
<br> �營(yíng)nvalidRequests:integer;�牐牐牐牐牐�
<br> end;
<br>
<br>var
<br> Form1:TForm1;
<br>
<br>implementation
<br>
<br>{$R*.DFM}
<br>
<br>file://系統(tǒng)啟動(dòng)定時(shí)器，啟動(dòng)窗顯示完成后，縮小到SystemTray…
<br>procedureTForm1.Timer2Timer(Sender:TObject);
<br>begin
<br> �爐imer2.Enabled:=false;�牐�
<br> �爏essions:=0;�牐牐牐牐牐牐�
<br> �燗pplication.OnException:=AppException;�牐�
<br> �爄nvalidRequests:=0;�牐牐牐牐�
<br> �燣ookUpTimeOut:=60000;�牐牐�
<br> �爐imer1.Enabled:=true;�牐牐牐�
<br> �爊11.Enabled:=false;�牐牐牐牐�
<br> �爊21.Enabled:=true;�牐牐牐牐�
<br> �爏erversocket1.Port:=988;�牐牐�
<br> �爏erversocket1.Active:=true;�牐�
<br> �爁orm1.hide;�牐牐牐牐牐牐牐爗隱藏界面，縮小到SystemTray上}
<br>end;
<br>
<br>file://開(kāi)啟服務(wù)菜單項(xiàng)…
<br>procedureTForm1.N11Click(Sender:TObject);
<br>begin
<br> �爏erversocket1.Active:=true;�牐�
<br>end;
<br>
<br>
<br>file://停止服務(wù)菜單項(xiàng)…
<br>procedureTForm1.N21Click(Sender:TObject);
<br>begin
<br> �爏erversocket1.Active:=false;�牐牐�
<br> �燦11.Enabled:=True;
<br> �燦21.Enabled:=False;
<br> �燬ervice_Enabled:=false;�牐牐牐牐�
<br>end;
<br>
<br>
<br>file://主窗口建立…
<br>procedureTForm1.FormCreate(Sender:TObject);
<br>begin
<br> �燬ervice_Enabled:=false;
<br> �爐imer2.Enabled:=true;�牐牐牐�
<br>end;
<br>
<br>file://窗口關(guān)閉時(shí)…
<br>procedureTForm1.FormClose(Sender:TObject;varAction:TCloseAction);
<br>begin
<br> �爐imer1.Enabled:=false;�牐牐牐牐�
<br> �爄fService_Enabledthen
<br> �牐爏erversocket1.Active:=false;��
<br>end;
<br>
<br>file://退出程序按鈕…
<br>procedureTForm1.N01Click(Sender:TObject);
<br>begin
<br> �爁orm1.Close;�牐牐牐牐牐牐牐牐牐�
<br>end;
<br>
<br>file://開(kāi)啟代理服務(wù)后…
<br>procedureTForm1.ServerSocket1Listen(Sender:TObject;
<br> Socket:TCustomWinSocket);
<br>begin
<br> �燬ervice_Enabled:=true;�牐牐牐牐牐�
<br> �燦11.Enabled:=false;
<br> �燦21.Enabled:=true;
<br>end;
<br>
<br>file://被代理端連接到代理服務(wù)器后，建立一個(gè)會(huì)話，并與套接字綁定…
<br>procedureTForm1.ServerSocket1ClientConnect(Sender:TObject;
<br> Socket:TCustomWinSocket);
<br>var
<br>i,j:integer;
<br>begin
<br> �爅:=-1;
<br> �爁ori:=1tosessionsdo�牐牐牐牐牐牐�
<br> �牐爄fnotsession[i-1].Usedandnotsession[i-1].CSocket.activethen
<br> �牐牐牐燽egin
<br> �牐牐牐牐爅:=i-1;�牐牐牐牐牐牐牐牐牐牐�
<br> �牐牐牐牐爏ession[j].Used:=true;�牐牐�
<br> �牐牐牐牐燽reak;
<br> �牐牐牐爀nd
<br> �牐爀lse
<br> �牐牐牐爄fnotsession[i-1].Usedandsession[i-1].CSocket.activethen
<br> �牐牐牐牐牐牐爏ession[i-1].CSocket.active:=false;
<br> �爄fj=-1then
<br> �牐燽egin�牐牐牐牐牐牐牐牐牐牐牐牐牐牐�
<br> �牐牐牐爅:=sessions;
<br> �牐牐牐爄nc(sessions);
<br> �牐牐牐爏etlength(session,sessions);
<br> �牐牐牐爏ession[j].Used:=true;�牐牐牐牐牐牐牐牐牐牐牐�
<br> �牐牐牐爏ession[j].CSocket:=TClientSocket.Create(nil);
<br> �牐牐牐爏ession[j].CSocket.OnConnect:=ClientSocket1Connect;
<br> �牐牐牐爏ession[j].CSocket.OnDisconnect:=ClientSocket1Disconnect;
<br> �牐牐牐爏ession[j].CSocket.OnError:=ClientSocket1Error;
<br> �牐牐牐爏ession[j].CSocket.OnRead:=ClientSocket1Read;
<br> �牐牐牐爏ession[j].CSocket.OnWrite:=ClientSocket1Write;
<br> �牐牐牐爏ession[j].Lookingup:=false;
<br> �牐爀nd;
<br> �爏ession[j].SS_Handle:=socket.socketHandle;�牐�
<br> �爏ession[j].Request:=false;�牐牐牐牐牐牐牐牐牐�
<br> �爏ession[j].client_connected:=true;�牐牐牐牐牐�
<br> �爏ession[j].remote_connected:=false;�牐牐牐牐�
<br> �爀dit1.text:=inttostr(sessions);
<br>end;
<br>
<br>file://被代理端斷開(kāi)時(shí)…
<br>procedureTForm1.ServerSocket1ClientDisconnect(Sender:TObject;
<br> Socket:TCustomWinSocket);
<br>var
<br>i,j,k:integer;
<br>begin
<br> �爁ori:=1tosessionsdo
<br> �牐爄f(session[i-1].SS_Handle=socket.SocketHandle)andsession[i-1].Usedthen
<br> �牐牐牐燽egin
<br> �牐牐牐牐爏ession[i-1].client_connected:=false;��
<br> �牐牐牐牐爄fsession[i-1].remote_connectedthen
<br> �牐牐牐牐牐牐爏ession[i-1].CSocket.active:=false��
<br> �牐牐牐牐爀lse
<br> �牐牐牐牐牐牐爏ession[i-1].Used:=false;�牐牐牐牐�
<br> �牐牐牐牐燽reak;
<br> �牐牐牐爀nd;
<br> �爅:=sessions;
<br> �爇:=0;
<br> �爁ori:=1tojdo�牐牐牐牐牐牐牐牐牐牐牐�
<br> �牐燽egin
<br> �牐牐牐爄fsession[j-i].Usedthen
<br> �牐牐牐牐燽reak;
<br> �牐牐牐爄nc(k);
<br> �牐爀nd;
<br> �爄fk%26gt;0then�牐牐牐牐牐牐牐牐牐牐牐牐�
<br> �牐燽egin
<br> �牐牐牐爏essions:=sessions-k;
<br> �牐牐牐爏etlength(session,sessions);
<br> �牐爀nd;
<br> �爀dit1.text:=inttostr(sessions);
<br>end;
<br>
<br>file://通信錯(cuò)誤出現(xiàn)時(shí)…
<br>procedureTForm1.ServerSocket1ClientError(Sender:TObject;
<br> Socket:TCustomWinSocket;ErrorEvent:TErrorEvent;
<br> varErrorCode:Integer);
<br>var
<br>i,j,k:integer;
<br>begin
<br> �爁ori:=1tosessionsdo
<br> �牐爄f(session[i-1].SS_Handle=socket.SocketHandle)andsession[i-1].Usedthen
<br> �牐牐牐燽egin
<br> �牐牐牐牐爏ession[i-1].client_connected:=false;��
<br> �牐牐牐牐爄fsession[i-1].remote_connectedthen
<br> �牐牐牐牐牐牐爏ession[i-1].CSocket.active:=false��
<br> �牐牐牐牐爀lse
<br> �牐牐牐牐牐牐爏ession[i-1].Used:=false;�牐牐牐牐�
<br> �牐牐牐牐燽reak;
<br> �牐牐牐爀nd;
<br> �爅:=sessions;
<br> �爇:=0;
<br> �爁ori:=1tojdo
<br> �牐燽egin
<br> �牐牐牐爄fsession[j-i].Usedthen
<br> �牐牐牐牐燽reak;
<br> �牐牐牐爄nc(k);
<br> �牐爀nd;
<br> �爄fk%26gt;0then
<br> �牐燽egin
<br> �牐牐牐爏essions:=sessions-k;
<br> �牐牐牐爏etlength(session,sessions);
<br> �牐爀nd;
<br> �爀dit1.text:=inttostr(sessions);
<br> �爀rrorcode:=0;
<br>end;
<br>
<br>file://被代理端發(fā)送來(lái)頁(yè)面請(qǐng)求時(shí)…
<br>procedureTForm1.ServerSocket1ClientRead(Sender:TObject;
<br> Socket:TCustomWinSocket);
<br>var
<br>tmp,line,host:string;
<br>i,j,port:integer;
<br>begin
<br> �爁ori:=1tosessionsdo�牐牐牐牐牐牐牐�
<br> �牐爄fsession[i-1].Usedand(session[i-1].SS_Handle=socket.sockethandle)then
<br> �牐牐牐燽egin
<br> �牐牐牐牐牐爏ession[i-1].request_str:=socket.ReceiveText;��
<br> �牐牐牐牐牐爐mp:=session[i-1].request_str;�牐牐牐牐牐牐牐�
<br> �牐牐牐牐牐爉emo1.lines.add(tmp);
<br> �牐牐牐牐牐爅:=pos(char(13)+char(10),tmp);�牐牐牐牐牐牐牐�
<br> �牐牐牐牐牐爓hilej%26gt;0do�牐牐牐牐牐牐牐牐牐牐�
<br> �牐牐牐牐牐牐燽egin
<br> �牐牐牐牐牐牐牐牐爈ine:=copy(tmp,1,j-1);�牐牐牐牐牐牐牐牐�
<br> �牐牐牐牐牐牐牐牐燿elete(tmp,1,j+1);�牐牐牐牐牐牐牐牐牐牐�
<br> �牐牐牐牐牐牐牐牐爅:=pos('Host',line);�牐牐牐牐牐牐牐牐牐�
<br> �牐牐牐牐牐牐牐牐爄fj%26gt;0then
<br> �牐牐牐牐牐牐牐牐牐燽egin
<br> �牐牐牐牐牐牐牐牐牐牐牐燿elete(line,1,j+5);�牐牐牐牐牐牐�
<br> �牐牐牐牐牐牐牐牐牐牐牐爅:=pos(':',line);
<br> �牐牐牐牐牐牐牐牐牐牐牐爄fj%26gt;0then
<br> �牐牐牐牐牐牐牐牐牐牐牐牐燽egin
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐爃ost:=copy(line,1,j-1);
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐燿elete(line,1,j);
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐爐ry
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐牐爌ort:=strtoint(line);
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐爀xcept
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐牐爌ort:=80;
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐爀nd;
<br> �牐牐牐牐牐牐牐牐牐牐牐牐爀nd
<br> �牐牐牐牐牐牐牐牐牐牐牐爀lse
<br> �牐牐牐牐牐牐牐牐牐牐牐牐燽egin
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐爃ost:=trim(line);�牐牐牐牐牐牐牐�
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐爌ort:=80;
<br> �牐牐牐牐牐牐牐牐牐牐牐牐爀nd;
<br> �牐牐牐牐牐牐牐牐牐牐牐爄fnotsession[i-1].remote_connectedthen��
<br> �牐牐牐牐牐牐牐牐牐牐牐牐燽egin
<br> �牐牐牐牐牐牐牐牐牐牐牐牐牐牐爏ession[i-1].Request:=true;�牐牐�