爲什麼此代碼用於檢查代理有效性崩潰？

Question

我的程序中有以下代碼。當我嘗試檢查代理是否是有效代理時，它會使我的程序崩潰。任何想法如何解決這一問題？我使用的是印10

if checkproxy('http://www.google.com') label1.text:='Good' else label1.text:='bad'; 

如果我嘗試調用另一個idHTTP請求checkproxy崩潰的程序之後連接。

這是實際的代碼....這將返回錯誤......

function TregForm.webSession(sURL : ansistring) : ansistring; 
    var sstream : Tstringstream; 
     httpcon : TIdHTTP; 
     antifreeze : TIdAntiFreeze; 
begin 
    result := ''; 
    sstream := tstringstream.Create(''); 
    try 
    if length(SettingsForm.edtProxyServer.text) >= 7 then // 0.0.0.0 
    if checkproxy(' http://www.google.com ') then 
    begin 
     antifreeze := TIdAntiFreeze.Create(nil); 
     httpcon := TIdHTTP.create; 
     httpcon.ProxyParams.BasicAuthentication:=true; 
     httpcon.ProxyParams.ProxyPassword:=SettingsForm.edtProxyPass.Text; 
     httpcon.ProxyParams.ProxyPort:=strtoint(SettingsForm.edtProxyPort.Text); 
     httpcon.ProxyParams.ProxyServer:=SettingsForm.edtProxyServer.Text; 
     httpcon.ProxyParams.ProxyUsername:=SettingsForm.edtProxyUserName.Text; 
    end 
    else 
    begin 
     showmessage('Proxy Server Not Working.. Attempting to bypass the Proxy'); 
     antifreeze := TIdAntiFreeze.Create(nil); 
     httpcon := TIdHTTP.create; 
     //httpcon.Request.ProxyConnection:=''; 
     //httpcon.ProxyParams.BasicAuthentication:=false; 
     //httpcon.ProxyParams.ProxyPassword:=''; 
     //httpcon.ProxyParams.ProxyPort:=0; 
     //httpcon.ProxyParams.ProxyServer:=''; 
     //httpcon.ProxyParams.ProxyUsername:=''; 
    end; 
    httpcon.HandleRedirects := true; 
    antifreeze.Active := true; 
    HttpCon.Get(sURL,sstream); 
    result := utf8towidestring(sstream.DataString); 
    except 
    httpcon.Disconnect; 
    end; 
    antifreeze.Active := false; 
    freeandnil(httpcon); 
    freeandnil(antifreeze); 
    freeandnil(sstream); 
end;
 

function TregForm.checkproxy(sURL : ansistring) : boolean; var //sstream : Tstringstream; httpcon : TIdHTTP; antifreeze : TIdAntiFreeze; begin result := true; try antifreeze := TIdAntiFreeze.Create(nil); httpcon := TIdHTTP.create; //sstream := tstringstream.Create(''); httpcon.ProxyParams.BasicAuthentication:=true; httpcon.ProxyParams.ProxyPassword:=SettingsForm.edtProxyPass.Text; httpcon.ProxyParams.ProxyPort:=strtoint(SettingsForm.edtProxyPort.Text); httpcon.ProxyParams.ProxyServer:=SettingsForm.edtProxyServer.Text; httpcon.ProxyParams.ProxyUsername:=SettingsForm.edtProxyUserName.Text;
 

httpcon.HandleRedirects := true; 
antifreeze.Active := true; 
HttpCon.Request.ProxyConnection:=SettingsForm.edtProxyServer.Text; 
HttpCon.head(sURL); 
httpCon.Disconnect; 
 

除了 在E：EIdException就開始 結果：= FALSE; 結束; 關於E：例外開始 // showmessage（'外部錯誤：'+＃13＃10 + E.Message）; showmessage（'Proxy Settings Error'）; 結果：= false; 結束; 結束; antifreeze.Active：= false; freeandnil（httpcon）; freeandnil（防凍液）; // freeandnil（sstream）; 結束;

錯誤消息：E001B844A模塊key.exe中的異常AccessViolation。 模塊'key.exe'中地址爲005B844A的訪問衝突。讀地址00000000

Answer 1

的在上面的代碼，如果「SettingsForm.edtProxyServer.text」小於7個字符，你將不得不在您使用防凍液和HttpCon無需先創建它們的情況。

我試驗了一下你的代碼，並在我的WinXP SP3（D2010，Indy v10.5.5）上進行了測試。這應該是工作代碼...

procedure TForm1.Button1Click(Sender: TObject); 
Var 
    Resp : String; 
begin 
    Resp := webSession('http://www.celarius.com'); 
    if Length(Resp)>0 then 
     MessageDlg('Got the body ok',mtInformation,[mbOk],0); 
end; 

function TForm1.webSession(sURL : ansistring) : ansistring; 
var 
    SStream : Tstringstream; 
    HTTPCon : TIdHTTP; 
    AntiFreeze : TIdAntiFreeze; 
begin 
    Result := ''; 
    if Length(SettingsForm.edtProxyServer.text) >= 7 then // 0.0.0.0 
    Try 
     SStream := NIL; 
     AntiFreeze := NIL; 
     HTTPCon := NIL; 
     Try 
      SStream := tstringstream.Create(''); 
      { Create & Set IdHTTP properties } 
      HTTPCon := TIdHTTP.create; 
      HTTPCon.HandleRedirects := true; 
      { Check Proxy } 
      if checkproxy('http://www.google.com') then 
      Begin 
       HTTPCon.ProxyParams.ProxyServer := SettingsForm.edtProxyServer.text; 
       HTTPCon.ProxyParams.ProxyPort := StrToInt(SettingsForm.edtProxyPort.Text); 
       HTTPCon.ProxyParams.BasicAuthentication := True; 
       HTTPCon.ProxyParams.ProxyUsername := SettingsForm.edtProxyServer.Text; 
       HTTPCon.ProxyParams.ProxyPassword := SettingsForm.edtProxyUserName.Text; 
      End; 
      { Create another AntiFreeze - only 1/app } 
      AntiFreeze := TIdAntiFreeze.Create(nil); 
      AntiFreeze.Active := true; 
      HTTPCon.Get(sURL,SStream); 
      Result := UTF8ToWideString(SStream.DataString); 
     Finally 
      If Assigned(HTTPCon) then FreeAndNil(HTTPCon); 
      If Assigned(AntiFreeze) then FreeAndNil(AntiFreeze); 
      If Assigned(SStream) then FreeAndNil(SStream); 
     End; 
    Except 
     { Handle exceptions } 
     On E:Exception do 
      MessageDlg('Exception: '+E.Message,mtError, [mbOK], 0); 
    End; 
end; 

function TForm1.checkproxy(sURL : ansistring) : boolean; 
var 
    HTTPCon : TIdHTTP; 
    AntiFreeze : TIdAntiFreeze; 
begin 
    Result := False; 
    Try 
     { Inti vars } 
     AntiFreeze := NIL; 
     HTTPCon := NIL; 
     Try 
      { AntiFreeze } 
      AntiFreeze := TIdAntiFreeze.Create(NIL); 
      AntiFreeze.Active := true; 
      { Create & Set IdHTTP properties } 
      HTTPCon := TIdHTTP.Create(NIL); 
      HTTPCon.ProxyParams.ProxyServer := SettingsForm.edtProxyServer.text; 
      HTTPCon.ProxyParams.ProxyPort := StrToInt(SettingsForm.edtProxyPort.Text); 
      HTTPCon.ProxyParams.BasicAuthentication := True; 
      HTTPCon.ProxyParams.ProxyUsername := SettingsForm.edtProxyServer.Text; 
      HTTPCon.ProxyParams.ProxyPassword := SettingsForm.edtProxyUserName.Text; 
      HTTPCon.HandleRedirects := true; 
      HTTPCon.ConnectTimeout := 1000; 
      HTTPCon.Request.Connection := 'close'; 
      HTTPCon.Head(sURL); 
     Finally 
      { Cleanup } 
      if Assigned(HTTPCon) then 
      Begin 
       { Return Success/Failure } 
       Result := HTTPCon.ResponseCode = 200; 
       If HTTPCon.Connected then HTTPCon.Disconnect; 
       FreeAndNil(HTTPCon); 
      End; 
      if Assigned(AntiFreeze) then FreeAndNil(AntiFreeze); 
     End; 
    Except 
     On E:EIdException do ; 
     { Handle exceptions } 
     On E:Exception do 
      MessageDlg('Exception: '+E.Message,mtError, [mbOK], 0); 
    End; 
end;