Pipes in Delphi for Command Prompt - delphi

How can I get Delphi to pass a string to the input pipe to a CMD process. I am able to get an error pipe and output pipe functioning properly, unfortunately not the input pipe. The code I am using is taken from an online tutorial for piping. There were several errors in the original code causing problems when it was compiled. They have been fixed but I am left with problems when trying to pass input still.
Here is the code in the Form.Create event. I also have included the WritePipe and ReadPipe methods. WritePipe does not work, ReadPipe does work. Both WriteFile and ReadFile in the Pipe methods return a successful message, only the ReadPipe actually works however.
var
DosApp: String;
DosSize: Integer;
Security : TSecurityAttributes;
start : TStartUpInfo;
byteswritten: DWord;
WriteString : ansistring;
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.hStdInput := InputPipeRead;
start.hStdOutput := OutputPipeWrite;
start.hStdError := ErrorPipeWrite;
start.dwFlags := STARTF_USESTDHANDLES + STARTF_USESHOWWINDOW;
start.wShowWindow := SW_Show;//SW_HIDE;
start.cb := SizeOf(start) ;
if CreateProcess('', PChar(DosApp), #Security, #Security, true,
CREATE_NEW_CONSOLE or SYNCHRONIZE, // CREATE_NO_WINDOW,
nil, nil, start, ProcessInfo) then
begin
MyThread := MainUnit.monitor.Create; // start monitor thread
MyThread.Priority := tpHigher;
end;
Button1.Enabled := true;
cmdcount := 1;
end;
Write Pipe:
procedure WritePipeOut(OutputPipe: THandle; InString: PWideChar);
// writes Instring to the pipe handle described by OutputPipe
var
count : integer;
byteswritten: DWord;
outputstring : PAnsiChar;
TextBuffer: array[1..32767] of AnsiChar;// char;
TextString: String;
begin
// most console programs require CR/LF after their input.
InString := PWideChar(InString + #13#10);
WriteFile(InputPipeWrite, InString[1], Length(InString), byteswritten, nil);
end;
Read Pipe:
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 AnsiChar;// char;
TextString: String;
BytesRead: Cardinal;
PipeSize: Integer;
begin
Result := '';
PipeSize := length(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;
Further note; this is for use with the Java Debugger, which requires input in stages and so I do not believe there is any alternative method other than manipulating input directly to the JDB.
Any help is much appreciated!

1) You should pass InputPipeRead as hStdInput into CreateProcess: uncomment your line start.hStdInput := InputPipeRead;
2) The WritePipeOut function has two errors: it writes a Unicode (UTF-16LE) string into a pipe, and it skips the first character (since it writes a memory area beginning at InString[1]). Instead of WriteFile(InputPipeWrite, InString[1], Length(InString),... you should write something like:
var AnsiBuf: AnsiString;
...
AnsiBuf := String(InString) + #13#10;
Write(InputPipeWrite, AnsiBuf[1], Length(AnsiBuf), byteswritten, nil);

Related

How to execute different commands from cmd in same cmd process?

I would like to start one cmd process and keep feeding it some different commands. I would like to get every text cmd output as soon as text is out. So far I have this:
function GetDosOutput(const ACommandLine: string;
AWorkDir: string = 'C:\'): string;
var
_SA: TSecurityAttributes;
_SI: TStartupInfo;
_PI: TProcessInformation;
_StdOutPipeRead, StdOutPipeWrite: THandle;
_WasOK: boolean;
_Buffer: array [0 .. 255] of AnsiChar;
_BytesRead: Cardinal;
_Handle: boolean;
begin
Result := '';
_SA.nLength := SizeOf(_SA);
_SA.bInheritHandle := True;
_SA.lpSecurityDescriptor := nil;
CreatePipe(_StdOutPipeRead, StdOutPipeWrite, #_SA, 0);
try
FillChar(_SI, SizeOf(_SI), 0);
_SI.cb := SizeOf(_SI);
_SI.dwFlags := STARTF_USESHOWWINDOW or STARTF_USESTDHANDLES;
_SI.wShowWindow := SW_HIDE;
_SI.hStdInput := GetStdHandle(STD_INPUT_HANDLE);
_SI.hStdOutput := StdOutPipeWrite;
_SI.hStdError := StdOutPipeWrite;
_Handle := CreateProcess(nil, PChar('cmd.exe /C ' + ACommandLine), nil, nil,
True, 0, nil, PChar(AWorkDir), _SI, _PI);
CloseHandle(StdOutPipeWrite);
if _Handle then
try
repeat
_WasOK := ReadFile(_StdOutPipeRead, _Buffer, 255, _BytesRead, nil);
if _BytesRead > 0 then
begin
_Buffer[_BytesRead] := #0;
Result := Result + string(_Buffer);
Application.ProcessMessages;
end;
until not _WasOK or (_BytesRead = 0);
WaitForSingleObject(_PI.hProcess, INFINITE);
finally
CloseHandle(_PI.hThread);
CloseHandle(_PI.hProcess);
end;
finally
CloseHandle(_StdOutPipeRead);
end;
end;
How do I keep same cmd.exe process and give it different commands, e.g.
1) ping stackoverflow.com, see its content as soon as one line is printed
2) ipconfig /all ?

Getting output from a shell/dos app into a Delphi app

I have a commandline application coded in delphi that I need to call from a normal desktop application (also coded in delphi). In short, I want to call the commandline app and display the text it outputs "live" in a listbox.
It's been ages since I have played around with the shell, but I distinctly remember that in order to grab the text from a commandline app - I have to use the pipe symbol ">". Like this:
C:/mycmdapp.exe >c:/result.txt
This will take any text printed to the shell (using writeLn) and dump it to a textfile called "result.txt".
But.. (and here comes the pickle), I want a live result rather than a backlog file. A typical example is the Delphi compiler itself - which manages to report back to the IDE what is going on. If my memory serves me correctly, I seem to recall that I must create a "pipe" channel (?), and then assign the pipe-name to the shell call.
I have tried to google this but I honestly was unsure of how to formulate it. Hopefully someone from the community can point me in the right direction.
Updated: This question might be identical to How do I run a command-line program in Delphi?. Some of the answers fit what I'm looking for, although the title and question itself is not identical.
As ever so often Zarco Gajic has a solution: Capture the output from a DOS (command/console) Window. This is a copy from his article for future reference:
The example runs 'chkdsk.exe c:\' and displays the output to Memo1.
Put a TMemo (Memo1) and a TButton (Button1) on your form. Put this code in the OnCLick event procedure for Button1:
procedure RunDosInMemo(DosApp: string; AMemo:TMemo);
const
READ_BUFFER_SIZE = 2400;
var
Security: TSecurityAttributes;
readableEndOfPipe, writeableEndOfPipe: THandle;
start: TStartUpInfo;
ProcessInfo: TProcessInformation;
Buffer: PAnsiChar;
BytesRead: DWORD;
AppRunning: DWORD;
begin
Security.nLength := SizeOf(TSecurityAttributes);
Security.bInheritHandle := True;
Security.lpSecurityDescriptor := nil;
if CreatePipe({var}readableEndOfPipe, {var}writeableEndOfPipe, #Security, 0) then
begin
Buffer := AllocMem(READ_BUFFER_SIZE+1);
FillChar(Start, Sizeof(Start), #0);
start.cb := SizeOf(start);
// Set up members of the STARTUPINFO structure.
// This structure specifies the STDIN and STDOUT handles for redirection.
// - Redirect the output and error to the writeable end of our pipe.
// - We must still supply a valid StdInput handle (because we used STARTF_USESTDHANDLES to swear that all three handles will be valid)
start.dwFlags := start.dwFlags or STARTF_USESTDHANDLES;
start.hStdInput := GetStdHandle(STD_INPUT_HANDLE); //we're not redirecting stdInput; but we still have to give it a valid handle
start.hStdOutput := writeableEndOfPipe; //we give the writeable end of the pipe to the child process; we read from the readable end
start.hStdError := writeableEndOfPipe;
//We can also choose to say that the wShowWindow member contains a value.
//In our case we want to force the console window to be hidden.
start.dwFlags := start.dwFlags + STARTF_USESHOWWINDOW;
start.wShowWindow := SW_HIDE;
// Don't forget to set up members of the PROCESS_INFORMATION structure.
ProcessInfo := Default(TProcessInformation);
//WARNING: The unicode version of CreateProcess (CreateProcessW) can modify the command-line "DosApp" string.
//Therefore "DosApp" cannot be a pointer to read-only memory, or an ACCESS_VIOLATION will occur.
//We can ensure it's not read-only with the RTL function: UniqueString
UniqueString({var}DosApp);
if CreateProcess(nil, PChar(DosApp), nil, nil, True, NORMAL_PRIORITY_CLASS, nil, nil, start, {var}ProcessInfo) then
begin
//Wait for the application to terminate, as it writes it's output to the pipe.
//WARNING: If the console app outputs more than 2400 bytes (ReadBuffer),
//it will block on writing to the pipe and *never* close.
repeat
Apprunning := WaitForSingleObject(ProcessInfo.hProcess, 100);
Application.ProcessMessages;
until (Apprunning <> WAIT_TIMEOUT);
//Read the contents of the pipe out of the readable end
//WARNING: if the console app never writes anything to the StdOutput, then ReadFile will block and never return
repeat
BytesRead := 0;
ReadFile(readableEndOfPipe, Buffer[0], READ_BUFFER_SIZE, {var}BytesRead, nil);
Buffer[BytesRead]:= #0;
OemToAnsi(Buffer,Buffer);
AMemo.Text := AMemo.text + String(Buffer);
until (BytesRead < READ_BUFFER_SIZE);
end;
FreeMem(Buffer);
CloseHandle(ProcessInfo.hProcess);
CloseHandle(ProcessInfo.hThread);
CloseHandle(readableEndOfPipe);
CloseHandle(writeableEndOfPipe);
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin {button 1 code}
RunDosInMemo('chkdsk.exe c:\',Memo1);
end;
Update:
The above example reads the output in one step. Here is another example from DelphiDabbler showing how the output can be read while the process is still running:
function GetDosOutput(CommandLine: string; Work: string = 'C:\'): string;
var
SA: TSecurityAttributes;
SI: TStartupInfo;
PI: TProcessInformation;
StdOutPipeRead, StdOutPipeWrite: THandle;
WasOK: Boolean;
Buffer: array[0..255] of AnsiChar;
BytesRead: Cardinal;
WorkDir: string;
Handle: Boolean;
begin
Result := '';
with SA do begin
nLength := SizeOf(SA);
bInheritHandle := True;
lpSecurityDescriptor := nil;
end;
CreatePipe(StdOutPipeRead, StdOutPipeWrite, #SA, 0);
try
with SI do
begin
FillChar(SI, SizeOf(SI), 0);
cb := SizeOf(SI);
dwFlags := STARTF_USESHOWWINDOW or STARTF_USESTDHANDLES;
wShowWindow := SW_HIDE;
hStdInput := GetStdHandle(STD_INPUT_HANDLE); // don't redirect stdin
hStdOutput := StdOutPipeWrite;
hStdError := StdOutPipeWrite;
end;
WorkDir := Work;
Handle := CreateProcess(nil, PChar('cmd.exe /C ' + CommandLine),
nil, nil, True, 0, nil,
PChar(WorkDir), SI, PI);
CloseHandle(StdOutPipeWrite);
if Handle then
try
repeat
WasOK := ReadFile(StdOutPipeRead, Buffer, 255, BytesRead, nil);
if BytesRead > 0 then
begin
Buffer[BytesRead] := #0;
Result := Result + Buffer;
end;
until not WasOK or (BytesRead = 0);
WaitForSingleObject(PI.hProcess, INFINITE);
finally
CloseHandle(PI.hThread);
CloseHandle(PI.hProcess);
end;
finally
CloseHandle(StdOutPipeRead);
end;
end;
You probably have the code on your harddisk already: the Execute function in the JclSysUtils unit of the JCL (JEDI Code Library) does what you need:
function Execute(const CommandLine: string; OutputLineCallback: TTextHandler;
RawOutput: Boolean = False; AbortPtr: PBoolean = nil): Cardinal;
You can supply it with a callback procedure:
TTextHandler = procedure(const Text: string) of object;
Did an answer too for better understanding:
{type TTextHandler =} procedure TTextHandlerQ(const aText: string);
begin
memo2.lines.add(atext);
end;
writeln(itoa(JExecute('cmd /C dir *.*',#TTextHandlerQ, true, false)));
You have to use /C then cmd /c is used to run commands in MS-DOS and terminate after command or process completion, otherwise it blocks output to memo.

Using WinInet to identify total file size before downloading it

I got the source below from a third-party site explaining how to download a file from the internet using WinInet. I'm not too familiar with API, and I took at look at the WinInet unit but did not see any API calls like what I need.
What I'm doing is adding the ability to report back progress of downloading a file. This procedure I've already wrapped inside of a TThread and everything works fine. However, just one missing piece: Finding the total size of the source file before downloading.
See below where I have a comment //HOW TO GET TOTAL SIZE? This is where I need to find out what is the total size of the file BEFORE I begin downloading it. How do I go about doing this? Because this code seems to not know the size of the file until it's done being downloaded - and that makes this addition irrelevant.
procedure TInetThread.Execute;
const
BufferSize = 1024;
var
hSession, hURL: HInternet;
Buffer: array[1..BufferSize] of Byte;
BufferLen: DWORD;
f: File;
S: Bool;
D: Integer;
T: Integer;
procedure DoWork(const Amt: Integer);
begin
if assigned(FOnWork) then
FOnWork(Self, FSource, FDest, Amt, T);
end;
begin
S:= False;
try
try
if not DirectoryExists(ExtractFilePath(FDest)) then begin
ForceDirectories(ExtractFilePath(FDest));
end;
hSession:= InternetOpen(PChar(FAppName), INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0);
try
hURL:= InternetOpenURL(hSession, PChar(FSource), nil, 0, 0, 0);
try
AssignFile(f, FDest);
Rewrite(f, 1);
T:= 0; //HOW TO GET TOTAL SIZE?
D:= 0;
DoWork(D);
repeat
InternetReadFile(hURL, #Buffer, SizeOf(Buffer), BufferLen);
BlockWrite(f, Buffer, BufferLen);
D:= D + BufferLen;
DoWork(D);
until BufferLen = 0;
CloseFile(f);
S:= True;
finally
InternetCloseHandle(hURL);
end
finally
InternetCloseHandle(hSession);
end;
except
on e: exception do begin
S:= False;
end;
end;
finally
if assigned(FOnComplete) then
FOnComplete(Self, FSource, FDest, S);
end;
end;
You can use the HEAD method and check the Content-Length to retrieve the file size of a remote file
Check these two Methods
WinInet
If you want execute a HEAD method you must use the HttpOpenRequest, HttpSendRequest and HttpQueryInfo WinInet functions .
uses
SysUtils,
Windows,
WinInet;
function GetWinInetError(ErrorCode:Cardinal): string;
const
winetdll = 'wininet.dll';
var
Len: Integer;
Buffer: PChar;
begin
Len := FormatMessage(
FORMAT_MESSAGE_FROM_HMODULE or FORMAT_MESSAGE_FROM_SYSTEM or
FORMAT_MESSAGE_ALLOCATE_BUFFER or FORMAT_MESSAGE_IGNORE_INSERTS or FORMAT_MESSAGE_ARGUMENT_ARRAY,
Pointer(GetModuleHandle(winetdll)), ErrorCode, 0, #Buffer, SizeOf(Buffer), nil);
try
while (Len > 0) and {$IFDEF UNICODE}(CharInSet(Buffer[Len - 1], [#0..#32, '.'])) {$ELSE}(Buffer[Len - 1] in [#0..#32, '.']) {$ENDIF} do Dec(Len);
SetString(Result, Buffer, Len);
finally
LocalFree(HLOCAL(Buffer));
end;
end;
procedure ParseURL(const lpszUrl: string; var Host, Resource: string);
var
lpszScheme : array[0..INTERNET_MAX_SCHEME_LENGTH - 1] of Char;
lpszHostName : array[0..INTERNET_MAX_HOST_NAME_LENGTH - 1] of Char;
lpszUserName : array[0..INTERNET_MAX_USER_NAME_LENGTH - 1] of Char;
lpszPassword : array[0..INTERNET_MAX_PASSWORD_LENGTH - 1] of Char;
lpszUrlPath : array[0..INTERNET_MAX_PATH_LENGTH - 1] of Char;
lpszExtraInfo : array[0..1024 - 1] of Char;
lpUrlComponents : TURLComponents;
begin
ZeroMemory(#lpszScheme, SizeOf(lpszScheme));
ZeroMemory(#lpszHostName, SizeOf(lpszHostName));
ZeroMemory(#lpszUserName, SizeOf(lpszUserName));
ZeroMemory(#lpszPassword, SizeOf(lpszPassword));
ZeroMemory(#lpszUrlPath, SizeOf(lpszUrlPath));
ZeroMemory(#lpszExtraInfo, SizeOf(lpszExtraInfo));
ZeroMemory(#lpUrlComponents, SizeOf(TURLComponents));
lpUrlComponents.dwStructSize := SizeOf(TURLComponents);
lpUrlComponents.lpszScheme := lpszScheme;
lpUrlComponents.dwSchemeLength := SizeOf(lpszScheme);
lpUrlComponents.lpszHostName := lpszHostName;
lpUrlComponents.dwHostNameLength := SizeOf(lpszHostName);
lpUrlComponents.lpszUserName := lpszUserName;
lpUrlComponents.dwUserNameLength := SizeOf(lpszUserName);
lpUrlComponents.lpszPassword := lpszPassword;
lpUrlComponents.dwPasswordLength := SizeOf(lpszPassword);
lpUrlComponents.lpszUrlPath := lpszUrlPath;
lpUrlComponents.dwUrlPathLength := SizeOf(lpszUrlPath);
lpUrlComponents.lpszExtraInfo := lpszExtraInfo;
lpUrlComponents.dwExtraInfoLength := SizeOf(lpszExtraInfo);
InternetCrackUrl(PChar(lpszUrl), Length(lpszUrl), ICU_DECODE or ICU_ESCAPE, lpUrlComponents);
Host := lpszHostName;
Resource := lpszUrlPath;
end;
function GetRemoteFileSize(const Url : string): Integer;
const
sUserAgent = 'Mozilla/5.001 (windows; U; NT4.0; en-US; rv:1.0) Gecko/25250101';
var
hInet : HINTERNET;
hConnect : HINTERNET;
hRequest : HINTERNET;
lpdwBufferLength: DWORD;
lpdwReserved : DWORD;
ServerName: string;
Resource: string;
ErrorCode : Cardinal;
begin
ParseURL(Url,ServerName,Resource);
Result:=0;
hInet := InternetOpen(PChar(sUserAgent), INTERNET_OPEN_TYPE_PRECONFIG, nil, nil, 0);
if hInet=nil then
begin
ErrorCode:=GetLastError;
raise Exception.Create(Format('InternetOpen Error %d Description %s',[ErrorCode,GetWinInetError(ErrorCode)]));
end;
try
hConnect := InternetConnect(hInet, PChar(ServerName), INTERNET_DEFAULT_HTTP_PORT, nil, nil, INTERNET_SERVICE_HTTP, 0, 0);
if hConnect=nil then
begin
ErrorCode:=GetLastError;
raise Exception.Create(Format('InternetConnect Error %d Description %s',[ErrorCode,GetWinInetError(ErrorCode)]));
end;
try
hRequest := HttpOpenRequest(hConnect, PChar('HEAD'), PChar(Resource), nil, nil, nil, 0, 0);
if hRequest<>nil then
begin
try
lpdwBufferLength:=SizeOf(Result);
lpdwReserved :=0;
if not HttpSendRequest(hRequest, nil, 0, nil, 0) then
begin
ErrorCode:=GetLastError;
raise Exception.Create(Format('HttpOpenRequest Error %d Description %s',[ErrorCode,GetWinInetError(ErrorCode)]));
end;
if not HttpQueryInfo(hRequest, HTTP_QUERY_CONTENT_LENGTH or HTTP_QUERY_FLAG_NUMBER, #Result, lpdwBufferLength, lpdwReserved) then
begin
Result:=0;
ErrorCode:=GetLastError;
raise Exception.Create(Format('HttpQueryInfo Error %d Description %s',[ErrorCode,GetWinInetError(ErrorCode)]));
end;
finally
InternetCloseHandle(hRequest);
end;
end
else
begin
ErrorCode:=GetLastError;
raise Exception.Create(Format('HttpOpenRequest Error %d Description %s',[ErrorCode,GetWinInetError(ErrorCode)]));
end;
finally
InternetCloseHandle(hConnect);
end;
finally
InternetCloseHandle(hInet);
end;
end;
Indy
Also check this code using indy.
function GetRemoteFilesize(const Url :string) : Integer;
var
Http: TIdHTTP;
begin
Http := TIdHTTP.Create(nil);
try
Http.Head(Url);
result:= Http.Response.ContentLength;
finally
Http.Free;
end;
end;
Answering the question of how to get a download size with WinInet. This is out of one of my file downloaders that is based on WinInet.
This is the method I use to get the download size:
function TWebDownloader.GetContentLength(URLHandle: HINTERNET): Int64;
// returns the expected download size. Returns -1 if one not provided
var
SBuffer: Array[1..20] of char;
SBufferSize: Integer;
srv: integer;
begin
srv := 0;
SBufferSize := 20;
if HttpQueryInfo(URLHandle, HTTP_QUERY_CONTENT_LENGTH, #SBuffer, SBufferSize, srv) then
Result := StrToFloat(String(SBuffer))
else
Result := -1;
end;
Use of this method requires an open request handle, and does NOT require reading any of the data:
URLHandle := HttpOpenRequest(ConnectHandle, 'GET', Pchar(sitepath), nil,
nil, nil, INTERNET_FLAG_NO_CACHE_WRITE, 0);
...
DownloadSize := GetContentLength(URLHandle);
HTH
after fixing the types it looks better like this:
function GetContentLength(URLHandle:HINTERNET):Int64;
// returns the expected download size. Returns -1 if one not provided
var
SBufferSize, srv:Cardinal;
begin
srv:=0;
SBufferSize:=20;
if Not HttpQueryInfo(URLHandle, HTTP_QUERY_CONTENT_LENGTH or HTTP_QUERY_FLAG_NUMBER, {#SBuffer} #Result, SBufferSize, srv) then Result:=-1;
end;
to call it:
{get the file handle}
hURL:=InternetOpenURL(hSession, PChar(URL), nil, 0, 0, 0);
if hURL=Nil then
begin
InternetCloseHandle(hSession);
ShowMessage('The link is incorrect!');
exit;
end;
{get the file size}
filesize:=GetContentLength(hURL);

Delphi: wait until bat-script runs to the end

I have bat-file, that make some operations. How to run this file from Delphi and wait, until it stops.
Something like that:
procedure TForm1.Button1Click(Sender: TObject);
begin
//Starting bat-file
bla-bla-bla
showmessage('Done');
end;
This executes the given command line and waits for the program started by the command line to exit. Returns true if the program returns a zero exit code and false if the program doesn't start or returns a non-zero error code.
function ExecAndWait(const CommandLine: string) : Boolean;
var
StartupInfo: Windows.TStartupInfo; // start-up info passed to process
ProcessInfo: Windows.TProcessInformation; // info about the process
ProcessExitCode: Windows.DWord; // process's exit code
begin
// Set default error result
Result := False;
// Initialise startup info structure to 0, and record length
FillChar(StartupInfo, SizeOf(StartupInfo), 0);
StartupInfo.cb := SizeOf(StartupInfo);
// Execute application commandline
if Windows.CreateProcess(nil, PChar(CommandLine),
nil, nil, False, 0, nil, nil,
StartupInfo, ProcessInfo) then
begin
try
// Now wait for application to complete
if Windows.WaitForSingleObject(ProcessInfo.hProcess, INFINITE)
= WAIT_OBJECT_0 then
// It's completed - get its exit code
if Windows.GetExitCodeProcess(ProcessInfo.hProcess,
ProcessExitCode) then
// Check exit code is zero => successful completion
if ProcessExitCode = 0 then
Result := True;
finally
// Tidy up
Windows.CloseHandle(ProcessInfo.hProcess);
Windows.CloseHandle(ProcessInfo.hThread);
end;
end;
end;
From: http://www.delphidabbler.com/codesnip?action=named&showsrc=1&routines=ExecAndWait
Here is some code and example - under Windows 7 works fine and is invisible
(funcion ExeAndWait is borrowed).
function ExeAndWait(ExeNameAndParams: string; ncmdShow: Integer = SW_SHOWNORMAL): Integer;
var
StartupInfo: TStartupInfo;
ProcessInformation: TProcessInformation;
Res: Bool;
lpExitCode: DWORD;
begin
with StartupInfo do //you can play with this structure
begin
cb := SizeOf(TStartupInfo);
lpReserved := nil;
lpDesktop := nil;
lpTitle := nil;
dwFlags := STARTF_USESHOWWINDOW;
wShowWindow := ncmdShow;
cbReserved2 := 0;
lpReserved2 := nil;
end;
Res := CreateProcess(nil, PChar(ExeNameAndParams), nil, nil, True,
CREATE_DEFAULT_ERROR_MODE
or NORMAL_PRIORITY_CLASS, nil, nil, StartupInfo, ProcessInformation);
while True do
begin
GetExitCodeProcess(ProcessInformation.hProcess, lpExitCode);
if lpExitCode <> STILL_ACTIVE then
Break;
Application.ProcessMessages;
end;
Result := Integer(lpExitCode);
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
ExeAndWait(ExtractFilePath(Application.ExeName) + 'test.bat', SW_HIDE);
ShowMessage('Done!');
end;
PS. If you like you can build batch file at runtime using TStringList class.

How in Delphi 2009 redirect console (stin, sterr)?

I try several samples in the internet and none of them work - the scripts are not executed- (maybe because are for pre Delphi 2009 unicode?).
I need to run some python scripts and pass arguments to them, like:
python "..\Plugins\RunPlugin.py" -a login -u Test -p test
And capture the output to a string & the errors to other.
This is what I have now:
procedure RunDosInMemo(DosApp:String; var OutData: String);
var
SA: TSecurityAttributes;
SI: TStartupInfo;
PI: TProcessInformation;
StdOutPipeRead, StdOutPipeWrite: THandle;
WasOK: Boolean;
Buffer: array[0..255] of Char;
BytesRead: Cardinal;
WorkDir: string;
Handle: Boolean;
begin
OutData := '';
with SA do begin
nLength := SizeOf(SA);
bInheritHandle := True;
lpSecurityDescriptor := nil;
end;
CreatePipe(StdOutPipeRead, StdOutPipeWrite, #SA, 0);
try
with SI do
begin
FillChar(SI, SizeOf(SI), 0);
cb := SizeOf(SI);
dwFlags := STARTF_USESHOWWINDOW or STARTF_USESTDHANDLES or CREATE_UNICODE_ENVIRONMENT;
wShowWindow := SW_HIDE;
hStdInput := GetStdHandle(STD_INPUT_HANDLE); // don't redirect stdin
hStdOutput := StdOutPipeWrite;
hStdError := StdOutPipeWrite;
end;
WorkDir := 'C:\';
Handle := CreateProcess(nil, PChar(DosApp),
nil, nil, True, 0, nil,
PChar(WorkDir), SI, PI);
CloseHandle(StdOutPipeWrite);
if Handle then
begin
try
repeat
WasOK := ReadFile(StdOutPipeRead, Buffer, 255, BytesRead, nil);
if BytesRead > 0 then
begin
Buffer[BytesRead] := #0;
OutData := OutData + String(Buffer);
end;
until not WasOK or (BytesRead = 0);
WaitForSingleObject(PI.hProcess, INFINITE);
finally
CloseHandle(PI.hThread);
CloseHandle(PI.hProcess);
end;
end else begin
raise Exception.Create('Failed to load python plugin');
end;
finally
CloseHandle(StdOutPipeRead);
end;
end;
Create_Unicode_Environment is a process creation flag, meant for use in the dwCreationFlags parameter of CreateFile. It is not a flag for use in the TStartupInfo record. API functions are liable to fail if you give them flag values they don't understand, and they're liable to do strange things if you give them flag values that mean something other than what you expected.
You declare a buffer of 256 Chars; recall that Char in Delphi 2009 is a 2-byte Unicode type. You then call ReadFile and tell it that the buffer is 255 bytes long instead of the real value, 512. When the documentation says that a value is the number of bytes, take that as your cue to use the SizeOf function.
Since ReadFile reads bytes, it would be a good idea to declare your buffer array to be an array of byte-sized elements, such as AnsiChar. That way, when you set Buffer[BytesRead], you won't include twice the data you actually read.
The Unicode version of CreateProcess may modify its command-line argument. You must ensure that the string you pass to that parameter has a reference count of 1. Call UniqueString(DosApp) before you call CreateProcess.
When an API function fails, you will of course want to know why. Don't just make up a reason. Use the functions provided, such as Win32Check and RaiseLastOSError. At the very least, call GetLastError, like MSDN tells you to. Don't throw a generic exception type when a more specific one is readily available.
I'm not certain the WaitForSingleObject is the way to go... I think its better to loop with GetExitCodeProcess(pi.hProcess,iExitCode) until iExitCode <> STILL_ACTIVE and then check for data on each pass through the loop.
The code as written does not operate under Delphi 2007 either, so its not a Delphi 2009 unicode issue.
Changing your inner loop to the following works:
if Handle then
begin
try
repeat
WasOK := ReadFile(StdOutPipeRead, Buffer, 255, BytesRead, nil);
for ix := 0 to BytesRead-1 do
begin
OutData := OutData + AnsiChar(Buffer[ix]);
end;
GetExitCodeProcess(pi.hProcess,iExit);
until (iExit <> STILL_ACTIVE);
finally
CloseHandle(PI.hThread);
CloseHandle(PI.hProcess);
end;
I made the following corrections/additions to the local variables:
Buffer: array[0..255] of byte;
iExit : Cardinal;
IX : integer;
I also moved the CloseHandle(StdOutPipeWrite) just before the close of the StdOutPipeRead.

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