Command Line Communication via Delphi

Question

I tried using delphi to send commands to the command line. However, I cannot do this because I used the CreateProcess method for this. I tried changing StdOutPipeWrite, however CreateProcess does not seem to allow the commands after passing through the initial CreateProcess command. Is there a way to use a descriptor to continue sending and receiving commands and messages with the command line and delphi?

Answer 1

My friend Glenn9999 from tek-tips.com wrote a good FAQ on this . I do not know if he was SO, but he deserves all of this. I copied the code from this page here for future reference. It uses channels for communication between the console and delphi.

unit mcunit; { written by Glenn9999 @ tek-tips.com. Posted here 6/21/2011 } interface uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type monitor = class(TThread) // pipe monitoring thread for console output private TextString: String; procedure UpdateCaption; protected procedure Execute; override; end; TForm1 = class(TForm) CommandText: TMemo; CommandRun: TComboBox; Button2: TButton; SaveDialog1: TSaveDialog; procedure FormDestroy(Sender: TObject); procedure Button2Click(Sender: TObject); procedure FormCreate(Sender: TObject); private { Private declarations } public { Public declarations } cmdcount: integer; end; var Form1: TForm1; InputPipeRead, InputPipeWrite: THandle; OutputPipeRead, OutputPipeWrite: THandle; ErrorPipeRead, ErrorPipeWrite: THandle; ProcessInfo : TProcessInformation; myThread: monitor; implementation {$R *.DFM} procedure WritePipeOut(OutputPipe: THandle; InString: string); // writes Instring to the pipe handle described by OutputPipe var byteswritten: DWord; begin // most console programs require CR/LF after their input. InString := InString + #13#10; WriteFile(OutputPipe, Instring[1], Length(Instring), byteswritten, nil); end; function ReadPipeInput(InputPipe: THandle; var BytesRem: Integer): String; { reads console output from InputPipe. Returns the input in function result. Returns bytes of remaining information to BytesRem } var TextBuffer: array[1..32767] of char; TextString: String; BytesRead: Integer; PipeSize: Integer; begin Result := ''; PipeSize := Sizeof(TextBuffer); // check if there is something to read in pipe PeekNamedPipe(InputPipe, nil, PipeSize, @BytesRead, @PipeSize, @BytesRem); if bytesread > 0 then begin ReadFile(InputPipe, TextBuffer, pipesize, bytesread, nil); // a requirement for Windows OS system components OemToChar(@TextBuffer, @TextBuffer); TextString := String(TextBuffer); SetLength(TextString, BytesRead); Result := TextString; end; end; procedure monitor.Execute; { monitor thread execution for console output. This must be threaded. checks the error and output pipes for information every 40 ms, pulls the data in and updates the memo on the form with the output } var BytesRem: DWord; begin while not Terminated do begin // read regular output stream and put on screen. TextString := ReadPipeInput(OutputPipeRead, BytesRem); if TextString <> '' then Synchronize(UpdateCaption); // now read error stream and put that on screen. TextString := ReadPipeInput(ErrorPipeRead, BytesRem); if TextString <> '' then Synchronize(UpdateCaption); sleep(40); end; end; procedure monitor.UpdateCaption; // synchronize procedure for monitor thread - updates memo on form. begin With Form1.CommandText.Lines do Add(TextString); end; procedure TForm1.FormDestroy(Sender: TObject); begin WritePipeOut(InputPipeWrite, 'EXIT'); // quit the CMD we started MyThread.Terminate; // close process handles CloseHandle(ProcessInfo.hProcess); CloseHandle(ProcessInfo.hThread); // close pipe handles CloseHandle(InputPipeRead); CloseHandle(InputPipeWrite); CloseHandle(OutputPipeRead); CloseHandle(OutputPipeWrite); CloseHandle(ErrorPipeRead); CloseHandle(ErrorPipeWrite); end; procedure TForm1.Button2Click(Sender: TObject); { takes the input from the command edit box and processes it } var UpText: String; begin UpText := UpperCase(CommandRun.Text); // done to eliminate case-sensitivity if UpText = 'CLR' then // clear the memo begin CommandText.Clear; WritePipeOut(InputPipeWrite, #13); end else if UpText = 'SAVELOG' then // save the memo box to a file. begin if SaveDialog1.Execute then begin CommandText.Lines.SaveToFile(SaveDialog1.FileName); CommandText.Lines.Add('Log file saved.'); end else CommandText.Lines.Add('Log file not saved.'); end // expand this, it needs to catch any variation where the command-interpreter // is called. Any different ideas? else if UpText = 'CMD' then inc(cmdcount) else if UpText = 'COMMAND' then inc(cmdcount) // terminate app if user types exit, else let alone else if UpText = 'EXIT' then begin if cmdcount = 1 then Application.Terminate else dec(cmdcount); end else WritePipeOut(InputPipeWrite, CommandRun.Text); CommandRun.Items.Add(CommandRun.Text); CommandRun.Text := ''; CommandRun.SetFocus; end; procedure TForm1.FormCreate(Sender: TObject); { upon form creation, this calls the command-interpreter, sets up the three pipes to catch input and output, and starts a thread to monitor and show the output of the command-interpreter } var DosApp: String; DosSize: Integer; Security : TSecurityAttributes; start : TStartUpInfo; begin CommandText.Clear; // get COMSPEC variable, this is the path of the command-interpreter SetLength(Dosapp, 255); DosSize := GetEnvironmentVariable('COMSPEC', @DosApp[1], 255); SetLength(Dosapp, DosSize); // create pipes With Security do begin nlength := SizeOf(TSecurityAttributes) ; binherithandle := true; lpsecuritydescriptor := nil; end; CreatePipe(InputPipeRead, InputPipeWrite, @Security, 0); CreatePipe(OutputPipeRead, OutputPipeWrite, @Security, 0); CreatePipe(ErrorPipeRead, ErrorPipeWrite, @Security, 0); // start command-interpreter FillChar(Start,Sizeof(Start),#0) ; start.cb := SizeOf(start) ; start.hStdInput := InputPipeRead; start.hStdOutput := OutputPipeWrite; start.hStdError := ErrorPipeWrite; start.dwFlags := STARTF_USESTDHANDLES + STARTF_USESHOWWINDOW; start.wShowWindow := SW_HIDE; if CreateProcess(nil, PChar(DosApp), @Security, @Security, true, CREATE_NEW_CONSOLE or SYNCHRONIZE, nil, nil, start, ProcessInfo) then begin MyThread := monitor.Create(false); // start monitor thread MyThread.Priority := tpHigher; end; Button2.Enabled := true; cmdcount := 1; end; end. 

Answer 2

First declare use:

 ShellAPI 

Then use this:

 ShellExecute(0, nil, 'cmd.exe', '/c **YOUR_COMMAND_HERE**', nil, HIDE_WINDOW);