The Implementation of an FTP Server

The MakeDirectory command enables us to create a new directory on the  server side. The event below does that by using Delphi's CreateDir function:

procedure TForm1.IdFTPServer1MakeDirectory(ASender:TIdFTPServerContext;
var VDirectory: String);
var
ldir:string;
begin
ldir:= setslashes(Homedir+VDirectory);
if not DirectoryExists(ldir) then
if not CreateDir(ldir) then
raise Exception.Create('Cannot create '+ldir);
end;

The retrieve file event enables the client to download a file. We use Tstreams to open and read a given file:

procedure TForm1.IdFTPServer1RetrieveFile(ASender:TIdFTPServerContext;
const AFileName: String; var VStream: TStream);
begin
VStream := TFileStream.Create(setSlashes

(HomeDir+AFilename),fmOpenRead);
end;

procedure TForm1.IdFTPServer1RenameFile(ASender:TIdFTPServerContext;
  const ARenameFromFile, ARenameToFile: String);
begin
if not Renamefile(ARenameFromFile,ARenameToFile) then
begin
   Raise Exception.Create('Could not rename file');
end;
end;

The event below executes when the client requests a directory to be removed. Here we use Delphi's RemoveDir() function to delete a directory:

procedure TForm1.IdFTPServer1RemoveDirectory(ASender:TIdFTPServerContext;
var VDirectory: String);
Var
LFile : String;
begin
LFile := setslashes(homedir + VDirectory);
if directoryexists(LFile) then begin
RemoveDir(LFile);
end
else
begin
Raise Exception.Create('Could not remove directory');
   end;
end;