Downloading a file in Delphi

Why not make use of Indy? If you use the TIdHTTP component, it's simple:

procedure TMyForm.DownloadFile;    var  IdHTTP1: TIdHTTP;  Stream: TMemoryStream;  Url, FileName: String;begin      Url := 'http://www.rejbrand.se';  Filename := 'download.htm';  IdHTTP1 := TIdHTTP.Create(Self);  Stream := TMemoryStream.Create;  try    IdHTTP1.Get(Url, Stream);    Stream.SaveToFile(FileName);  finally    Stream.Free;    IdHTTP1.Free;  end;end;

You can even add a progress bar by using the OnWork and OnWorkBegin events:

procedure TMyForm.IdHTTPWorkBegin(ASender: TObject; AWorkMode: TWorkMode;AWorkCountMax: Int64);begin  ProgressBar.Max := AWorkCountMax;  ProgressBar.Position := 0;end;procedure TMyForm.IdHTTPWork(ASender: TObject; AWorkMode: TWorkMode; AWorkCount: Int64);begin  ProgressBar.Position := AWorkCount;end;procedure TMyForm.DownloadFile;    var  IdHTTP1: TIdHTTP;  Stream: TMemoryStream;  Url, FileName: String;begin      Url := 'http://www.rejbrand.se';  Filename := 'download.htm';  IdHTTP1 := TIdHTTP.Create(Self);  Stream := TMemoryStream.Create;  try    IdHTTP1.OnWorkBegin := IdHTTPWorkBegin;    IdHTTP1.OnWork := IdHTTPWork;    IdHTTP1.Get(Url, Stream);    Stream.SaveToFile(FileName);  finally    Stream.Free;    IdHTTP1.Free;  end;end;

I'm not sure if these events fire in the context of the main thread, so any updates done to VCL components may have to be done using the TIdNotify component to avoid threading issues. Maybe someone else can check that.

The second approach is the standard way of using Internet resources using WinINet, a part of Windows API. I have used it a lot, and it has always worked well. The first approach I have never tried. (Neither is "very complicated". There will always be a few additional steps when using the Windows API.)

If you want a very simple method, you could simply call UrlMon.URLDownloadToFile. You will not get any fine control (at all!) about the download, but it is very simple.

Example:

URLDownloadToFile(nil,                  'http://www.rejbrand.se',                  PChar(ExtractFilePath(Application.ExeName) + 'download.htm'),                  0,                  nil);

For people that has later version of delphi, you can use this:

var  http : TNetHTTPClient;  url : string;  stream: TMemoryStream;begin  http := TNetHTTPClient.Create(nil);  stream := TMemoryStream.Create;  try    url := YOUR_URL_TO_DOWNLOAD;    http.Get(url, stream);    stream.SaveToFile('D:\Temporary\1.zip');  finally    stream.Free;    http.Free;  end;end;