Delphi 7: how to execute shell command and check the result?

Question

I'm using Delphi 7 and can't predict the target version of Windows.

I need to create a database (probably MySql, but might be something else) and define some table structures. I do not need to populate any data. Unfortunately, all of the ADO components seem to expect that a database already exists and they will then allow you to manipulate it.

So, since it's only a few simple commands, I thought that I might as well use ShellExectute().

Agree? Disagree?

Can anyone give me a sample code which will attempt to run "MySql --version" and let me check the result? After that I should be able to figure it out for myself. Thanks.

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[edit]

No offence intended, but I do know how to google. It's just that I don't find useful results. It's my own fault for not being explicit in this question, so please accept my apology - what I need is a code example, not just the name of a component.

Sorry (and thanks for the replies so far (all of which are +1))

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[edit]

The links which Robert gives do the job (procedure RunDosInMemo() does the trick) ... B U T you Must remember to include an .exe extension (so, 'notepad.exe', not just 'notepad', and to ge a full path if your command is not on the path.

Answer 1

I wonder why everybody who wants launch a new process tends to use ShellExecute instead, which is designed to open file in associated application?

You want new process? Then use CreateProcess. End of story.

CreateProcess allows you to wait for process, to get its exit code, to read its console output and many more.

Answer 2

Here is an article that explains it detail

Capture the output from a DOS (command/console) Window

But in short you need to Create two pipes to read and write the output. Then you need to set StdInput and StdOutput in the TStartUpInfo structure, then pass this structure to the CreateProcess() call.

Here is another article that shows how to Wait for the process to finish.

Answer 3

What you are looking for, probably, is an embedded database. Some options:

• Firebird Embedded
• MySQL Embedded
• SQLite

With either of databases and with appropriate data access components (not sure about ADO support for embedded FB and MySQL), you will be able to:

• attach without a DB
• create a DB
• then create the tables

Answer 4

Use DSiExecuteAndCapture from DSiWin32:

var
  exitCode: integer;
  output  : TStringList;
begin
  output := TStringList.Create;
  try
    if DSiExecuteAndCapture('mysql --version', output, '', exitCode) = 0 then
      Log(Format('error %d, cannot start', [GetLastError])) 
    else begin
      // check exitCode and output
    end;
  finally FreeAndNil(output); end;
end;

Answer 5

I saved this from a newsgroup post a long time ago; I don't know who originall wrote it, though.

This code allows you to run a DOS application and capture it's output in a TMemo. You can then pull what you need out of the memo with a little trial and error parsing the lines.

procedure TFMainForm.RunDosInMemo(const DosApp: String; AMemo: TRichEdit);
const
  ReadBuffer = 2400;
var
  Security : TSecurityAttributes;
  StdInPipeR, StdInPipeW : THandle;
  StdOutPipeR, StdOutPipeW : THandle;
  StartInfo : TStartUpInfo;
  ProcessInfo : TProcessInformation;
  Buffer : PByte;
  BytesAvailable, BytesRead : DWord;
  sDosApp: String;
  sData: RawByteString;
begin
  sDosApp := DosApp;
  UniqueString(sDosApp);

  with Security do begin
    nLength := SizeOf(TSecurityAttributes);
    bInheritHandle := True;
    lpSecurityDescriptor := nil;
  end;

  if CreatePipe(StdInPipeR, StdInPipeW, @Security, 0) then
  try

    SetHandleInformation(StdInPipeW, HANDLE_FLAG_INHERIT, 0);
    if CreatePipe(StdOutPipeR, StdOutPipeW, @Security, 0) then
    try
      SetHandleInformation(StdOutPipeR, HANDLE_FLAG_INHERIT, 0);
      GetMem(Buffer, ReadBuffer);
      try
        ZeroMemory(@StartInfo, SizeOf(StartInfo));
        StartInfo.cb := SizeOf(StartInfo);
        StartInfo.hStdOutput := StdOutPipeW;
        StartInfo.hStdInput := StdInPipeR;
        StartInfo.dwFlags := STARTF_USESTDHANDLES or STARTF_USESHOWWINDOW;
        StartInfo.wShowWindow := SW_HIDE;

        if CreateProcess(nil, 
                         PChar(sDosApp), 
                         nil, 
                         nil, 
                         True, 
                         NORMAL_PRIORITY_CLASS, 
                         nil, 
                         nil, 
                         StartInfo, 
                         ProcessInfo) then
          try
            while WaitForSingleObject(ProcessInfo.hProcess, 500) <> WAIT_TIMEOUT do
              Application.ProcessMessages;
            while PeekNamedPipe(StdOutPipeR, nil, 0, nil, BytesAvailable, nil) do 
            begin
              if BytesAvailable < 1 then 
                Break;
              if BytesAvailable > ReadBuffer then 
                BytesAvailable := ReadBuffer;
              if not ReadFile(StdOutPipeR, 
                              Buffer[0], 
                              BytesAvailable, 
                              BytesRead, 
                              nil) then 
                Break;
              SetString(sData, PAnsiChar(Buffer), BytesRead);
              // assign an appropriate codepage for the output data:
              // 0 for default Ansi, 1252 or 20157 for ASCII, 1200 for 
              // Unicode, etc...
              SetCodePage(sData, ...);
              // this is faster and more efficient than reading/writing the 
              // Text property directly...
              AMemo.SelStart := AMemo.GetTextLen;
              AMemo.SelLength := 0;
              AMemo.SelText := sData;
            end;
          finally
            CloseHandle(ProcessInfo.hThread);
            CloseHandle(ProcessInfo.hProcess);
          end;
      finally
        FreeMem(Buffer);
      end;
    finally
      CloseHandle(StdOutPipeR);
      CloseHandle(StdOutPipeW);
    end;
  finally
    CloseHandle(StdInPipeR);
    CloseHandle(StdInPipeW);
  end;
end;

Answer 6

I wrote a unit and set of components to handle console redirection in delphi quite a long time ago:

http://www.fulgan.com/delphi/dospipes15.zip

But beyond that, you shouldn't have to go through that: use the ADO connection component just to connect to the database's default catalog and then use the "execute" method to create whatever database and schema you need. The database SERVER need to be properly installed and running for this to work but, at least with MSSQL, there is no problem with creating new databases this way. the exact connection string to use might change depending on the target DB, though.