Download form - which library to use?
lazarus / 38-Networking and Web Programming

----------------------------------------------------------------------
mesiarm · 2013-06-27 14:28

Hi. I want to make some download form with progress bar something like
VLC player has  - when you click to download update. How to make it
and which library (Synapse, Indy etc.) to use? I have Synapse,but i´m
not sure if there is something to use progress bar and download big
files (I want to download around 30 MB file).

----------------------------------------------------------------------
Rails · 2013-06-27 15:33

Use TProgressBar in ComCtrls.

----------------------------------------------------------------------
Leledumbo · 2013-06-27 15:43

All available networking libraries (fcl-net, synapse, lnet, indy) are
AFAIK capable of doing this.
Synapse:
http://synapse.ararat.cz/doku.php/public:howto:ftp_progressbar
(applicable to THTTPSend, only change from DSock to Sock to get the
socket instance).

----------------------------------------------------------------------
mesiarm · 2013-06-28 20:05

thanks.... i tried it i made this program ...I don´t know.. how to
continue....

i looked to this
http://www.ararat.cz/synapse/doku.php/public:howto:onstatus
i tried
Code: [Select]http.Sock.OnStatus := SockPutCallBack(Sender:
TObject,HR_ReadCount, value)
I´m not sure with parameters and I don´t know which value to use

Can you explain me a bit working of this program  please?

Code: [Select]unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
ComCtrls,
  StdCtrls, blcksock, synafpc, synsock, synautil, synacode, synaip,
httpsend;

type

  { TForm1 }

  TForm1 = class(TForm)
    httpclick: TButton;
    pr: TProgressBar;
    procedure httpclickClick(Sender: TObject);
  private
    { private declarations }
  public
    procedure SockPutCallBack(Sender: TObject;
  Reason: THookSocketReason; const Value: string);
    { public declarations }
  end;

var
  Form1: TForm1;
  CurrentBytes,TotalBytes : integer;
  http : THttpsend;
implementation

{$R *.lfm}



procedure TForm1.SockPutCallBack(Sender: TObject;
  Reason: THookSocketReason; const Value: string);
begin
  case Reason of
    HR_WriteCount: // HR_ReadCount // Value contains number of bytes
      begin
        inc(CurrentBytes, StrToIntDef(Value, 0)); // Increment
uploaded bytes
        pr.Position := Round(1000 * (CurrentBytes / TotalBytes));
      end;
    HR_Connect: CurrentBytes := 0; // Reset
    (*
      else
        begin
          v := getEnumName(typeInfo(THookSocketReason),
            integer(Reason)) + ' ' + Value);
          MemoLog.Lines.Add(v); // Show log in a Memo field
        end;
    *)
  end;
end;
procedure TForm1.httpclickClick(Sender: TObject);
begin
  http := THTTPSend.Create;
    try
      http.Sock.OnStatus := SockPutCallBack;
      finally
        http.free;
      end;
end;

end.

----------------------------------------------------------------------
Jurassic Pork · 2013-06-29 00:18

hello,
1 - you must get the size of the file which you want to download
before downloading, to have the TotalBytes value.
2 - The downloading procedure need to be in a thread else your Form
will freeze while download.

here is an example  ( not sure, must be checked) :
Code: [Select]unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics,
  Dialogs, StdCtrls, ComCtrls, httpsend,blcksock,typinfo, synamisc;

type
   { THTTPDownload }

  THTTPDownload = class(TThread)
    private
      http : THTTPsend;
      TotalBytes    :  integer;
      CurrentBytes  :  integer;
      fURL: string;
      fFileName: string;
    procedure SocketGetCallBack(Sender: TObject; Reason:
THookSocketReason;
    const Value: string);
    public
      constructor Create(URL, FileName: string);
      procedure Execute; override;
  end;

  { TForm1 }

  TForm1 = class(TForm)
    Button1: TButton;
    ELink: TEdit;
    ProgressBar1: TProgressBar;
    procedure Button1Click(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}
{ THTTPDownload }

constructor THTTPDownload.Create(URL, FileName: string);
begin
  inherited Create(True);
  fURL:= URL;
  fFileName:= FileName;
end;
procedure THTTPDownload.SocketGetCallBack(Sender: TObject; Reason:
THookSocketReason;
  const Value: string);
begin
  if TotalBytes=0 then
    exit;
  case Reason of
    HR_ReadCount:
    begin
      Inc(CurrentBytes, StrToIntDef(Value, 0));
      Form1.ProgressBar1.Position := Round(100 * (CurrentBytes /
TotalBytes));
    end;
    HR_Connect: CurrentBytes := 0;
  end;
end;

procedure THTTPDownload.Execute;
const
  MaxRetries=3;
var
  HTTPGetResult: boolean;
  RetryAttempt: integer;
  i:integer;
  s:string;
  httpresult : boolean;
begin
  httpresult:=false;
  RetryAttempt:=1;
  http :=THTTPSend.Create;
  http.Sock.OnStatus := @SocketGetCallBack;
  try
    try
      // try to get the file size
      if http.HTTPMethod('HEAD', fURL) then
         begin
       // search for "Content-Length:" in header
            for i:=0 to http.Headers.Count-1 do
            begin
             s:=UpperCase(http.Headers[i]);
              if pos('CONTENT-LENGTH:',s)>0 then
              TotalBytes :=
StrToIntDef(copy(s,pos(':',s)+1,length(s)),0);
              end;
          http.Headers.Clear;

         end;
      // Try to get the file
      HTTPGetResult:=http.HTTPMethod('GET', fURL);
      while (HTTPGetResult=false) and (RetryAttempt<MaxRetries) do
      begin
        sleep(500*RetryAttempt);
        HTTPGetResult:=http.HTTPMethod('GET', fURL);
        RetryAttempt:=RetryAttempt+1;
      end;
      // If we have an answer from the server, check if the file
      // was sent to us.
      case http.Resultcode of
        100..299:
          begin
            with TFileStream.Create(fFileName,fmCreate or fmOpenWrite)
do
            try
              Seek(0, soFromBeginning);
              CopyFrom(http.Document, 0);
            finally
              Free;
            end;
            httpresult:=true;
          end; //informational, success
        300..399: httpresult:=false; //redirection. Not implemented,
but could be.
        400..499: httpresult:=false; //client error; 404 not found etc
        500..599: httpresult:=false; //internal server error
        else httpresult:=false; //unknown code
      end;
    except
      // We don't care for the reason for this error; the download
failed.
      httpresult:=false;
    end;
  finally
    http.Free;
  end;
end;

{ TForm1 }


procedure TForm1.Button1Click(Sender: TObject);
  var i:integer;
  s:string;
  download: THTTPDownload;
begin
  Progressbar1.Position := 0;
  download:= THTTPDownload.Create(Elink.Text,'file.dwl');
 // download.OnTerminate:= @DownloadTerminiated;
  download.Resume;
end;

end.
Friendly,  J.P

----------------------------------------------------------------------
mesiarm · 2013-06-30 09:29

Thank you   It works. I edited it bit and I want to ask - How to
implement redirect? For example if I want to download from 
http://get.videolan.org/vlc/2.0.7/win32/vlc-2.0.7-win32.exe it returns
only few Kb file because it won´t redirect ..... And is there chance
to even download latest version? maybe download from folder
http://get.videolan.org:81/vlc/last/win32/ .... and else .... how can
I extract domain from url? I tried more examples with basic pos
function  but i didn´t worked

----------------------------------------------------------------------
Leledumbo · 2013-06-30 10:18

QuoteHow to implement redirect? For example if I want to download
from  http://get.videolan.org/vlc/2.0.7/win32/vlc-2.0.7-win32.exe it
returns only few Kb file because it won´t redirectNothing is magical,
so you have to go down to lower level a bit. That page returns html
with this fragment:
Quote<meta http-equiv="refresh" content="5;URL='http://free.nchc.org.t
w/vlc/vlc/2.0.7/win32/vlc-2.0.7-win32.exe'" />The bold part is the
real URL that directly gets the file. Scan that meta tag (manual
parsing should be enough, full html parsing could be slow).
QuoteAnd is there chance to even download latest version? maybe
download from folder http://get.videolan.org:81/vlc/last/win32/You
know the URL, so just do it. Many repo provide a "symlink" to the
latest version, without specific version in the filename, but VLC
doesn't seem to follow that so you still have to scan the html.
Assuming the filename format doesn't change, you could just look for
.exe suffix (there's only one file).
Quoteand else .... how can I extract domain from url? I tried more
examples with basic pos function  but i didn´t
workedhttp://www.freepascal.org/docs-html/fcl/uriparser/index.html

----------------------------------------------------------------------
mesiarm · 2013-07-07 18:47

Thank you for advices. I´ll try it, but how to access http directory
list, since there is no index.html file? ...and I have one other
problem... i have main form which opens updater form as
modal(Showmodal) and when i click on button in updater form it start
downloading...and in thread in code above I have problem communicating
with updater form and it´s progressbar. It raises exception while
accesing to progressbar and when I use assigned(updaterform) in button
onclick it returns false. It worked when I had it as separate form in
test project, but stopped working, when I added it to my project. I
dont know, where can be I mistake....

----------------------------------------------------------------------
Jurassic Pork · 2013-07-08 03:01

hello,
with this code it's OK for me (unit2 contains Updater form modal with
a progressbar) :
Code: [Select]unit Unit2;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
ComCtrls,
  httpsend,blcksock,typinfo, synamisc;

type
    { THTTPDownload }

  THTTPDownload = class(TThread)
    private
      http : THTTPsend;
      TotalBytes    :  integer;
      CurrentBytes  :  integer;
      fURL: string;
      fFileName: string;
    procedure SocketGetCallBack(Sender: TObject; Reason:
THookSocketReason;
    const Value: string);
     procedure downloadterminated(Sender: TObject);

    public
      constructor Create(URL, FileName: string);
      procedure Execute; override;
  end;

  { TUpdater }

  TUpdater = class(TForm)
    ProgressBar1: TProgressBar;

  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Updater: TUpdater;

implementation

{$R *.lfm}

{ THTTPDownload }

constructor THTTPDownload.Create(URL, FileName: string);
begin
  inherited Create(True);
  fURL:= URL;
  fFileName:= FileName;
  OnTerminate := @downloadterminated;
end;

procedure THTTPDownload.downloadterminated(Sender: TObject);
 begin
 Updater.Close;
 end;
procedure THTTPDownload.SocketGetCallBack(Sender: TObject; Reason:
THookSocketReason;
  const Value: string);
begin
  if TotalBytes=0 then
    exit;
  case Reason of
    HR_ReadCount:
    begin
      Inc(CurrentBytes, StrToIntDef(Value, 0));
      Updater.ProgressBar1.Position := Round(100 * (CurrentBytes /
TotalBytes));
    end;
    HR_Connect: CurrentBytes := 0;
  end;
end;

procedure THTTPDownload.Execute;
const
  MaxRetries=3;
var
  HTTPGetResult: boolean;
  RetryAttempt: integer;
  i:integer;
  s,Redirstr:string;
  httpresult : boolean;
  TextHttp : TStringList;
begin
  httpresult:=false;
  RetryAttempt:=1;
  Texthttp := TStringList.Create();
  http :=THTTPSend.Create;
  http.Sock.OnStatus := @SocketGetCallBack;
  try
    try
      // try to get the file size
      if http.HTTPMethod('HEAD', fURL) then
         begin
       // search for "Content-Length:" in header
            for i:=0 to http.Headers.Count-1 do
            begin
             s:=UpperCase(http.Headers[i]);
              if pos('CONTENT-LENGTH:',s)>0 then
              TotalBytes :=
StrToIntDef(copy(s,pos(':',s)+1,length(s)),0);
              end;
          http.Headers.Clear;

         end;
      // Try to get the file
      HTTPGetResult:=http.HTTPMethod('GET', fURL);
      while (HTTPGetResult=false) and (RetryAttempt<MaxRetries) do
      begin
        sleep(500*RetryAttempt);
        HTTPGetResult:=http.HTTPMethod('GET', fURL);
        RetryAttempt:=RetryAttempt+1;
      end;
      // If we have an answer from the server, check if the file
      // was sent to us.
      case http.Resultcode of
        100..299:
          begin
            with TFileStream.Create(fFileName,fmCreate or fmOpenWrite)
do
            try
              Seek(0, soFromBeginning);
              CopyFrom(http.Document, 0);
            finally
              Free;
            end;
            httpresult:=true;
          end; //informational, success
        300..399: begin
                  Texthttp.LoadFromStream(http.document);
 //                 RedirStr := HTTPGetResult.
                  httpresult:=false; //redirection. Not implemented,
but could be.
                  end;
        400..499: httpresult:=false; //client error; 404 not found etc
        500..599: httpresult:=false; //internal server error
        else httpresult:=false; //unknown code
      end;
    except
      // We don't care for the reason for this error; the download
failed.
      httpresult:=false;
    end;
  finally
    http.Free;
  end;
end;
end. 
call from Form1 :
Code: [Select]procedure TForm1.Button1Click(Sender: TObject);
  var i:integer;
  s:string;
  download: THTTPDownload;
begin
  Updater.Progressbar1.Position := 0;
  download:= THTTPDownload.Create(Elink.Text,'file.dwl');
  download.Resume;
  Updater.ShowModal;
  download.free;
end;
Code not safe (you must add exception management, etc...)

friendly, J.P

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mesiarm · 2013-07-08 18:29

thanks..  I would rather control download thread from second form
since it´s declared there and I don´t want to move it. I know that
there is some problem with forms, because when i have set updater as
the main form (right after Application.Initialize) it worked. But
normally when I call assigned(updater) in onclick button it returns
false ...and raises excteption, when thread tries to comunicate with
updater form.      I also tried creating
Application.Createform(Tupdater, updater) in main form without
success...What could be a problem ? I have also tried updater.Show
instead of Showmodal.....

----------------------------------------------------------------------
mesiarm · 2013-07-08 18:31

and please how to read the http directory list? since
http://get.videolan.org:81/vlc/last/win32/ doesnt have any index.html
file.....

----------------------------------------------------------------------
Jurassic Pork · 2013-07-09 00:56

for your first problem, please post in attachment or show in a message
your source project to see what is wrong (sorry i don't understand how
are your forms).
for http directory list , here is an experimental code (not sure than
the reg expression is the best one) using regexpr to parse html (
because http directory listing is a html page) .
1 - to use regexpr unit add :
Code: [Select]uses regexpr;2 - put the html text returned from
"http://get.videolan.org:81/vlc/last/win32/"   in a tstringlist :
Code: [Select]var TextHttp : TStringList;
...
 Texthttp := TStringList.Create();     
...
 Texthttp.LoadFromStream(http.document);
and here is a procedure to extract directory list   with regexpr :
Code: [Select]procedure ListHTTPFiles(httpText : TstringList);   //
J.P  July 2013
var x: integer;
   re: TRegExpr;
    s : string;
begin
  re := TRegExpr.Create;
  // expression to extract href and value from html line like :
  // <li><a href="vlc-2.0.7-win32.7z"> vlc-2.0.7-win32.7z</a></li>
  re.Expression := '<li><a href=\"(.*)\">(.*)</a>.+';
  For x := 0 to httpText.Count -1  do
  begin
  s := httpText.Strings[x];
  if re.Exec(s) then
  ShowMessage('href : ' + re.Match[1] + ' - value : ' + re.Match[2]);
  end;
  re.Free;
end;
called from this line :
Code: [Select]ListHTTPFiles(Texthttp);
friendly, J.P

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mesiarm · 2013-07-09 18:12

I think it is a bit complicated with my project so I will post a image
Code: [Select]http://img199.imageshack.us/img199/5716/ddyb.png

----------------------------------------------------------------------
mesiarm · 2013-07-12 14:28

i tried your procedure and it works. I have changed it to function and
added .exe suffix to regural expression and it works, but i don´t know
when call this function, because if I call it at beggining
http.document is empty and later it points to url to directory. Should
I make second connection or?

----------------------------------------------------------------------
Jurassic Pork · 2013-07-12 14:58

hello,
here is  the code  for   procedure      THTTPDownload.Execute;  ( the
game : find where is  ListHTTPFiles function   )

Code: [Select]procedure THTTPDownload.Execute;
const
  MaxRetries=3;
var
  HTTPGetResult: boolean;
  RetryAttempt: integer;
  i:integer;
  s,Redirstr:string;
  httpresult : boolean;
  TextHttp : TStringList;
begin
  httpresult:=false;
  RetryAttempt:=1;
  Texthttp := TStringList.Create();
  http :=THTTPSend.Create;
  http.Sock.OnStatus := @SocketGetCallBack;
  try
    try
      // try to get the file size
      if http.HTTPMethod('HEAD', fURL) then
         begin
       // search for "Content-Length:" in header
            for i:=0 to http.Headers.Count-1 do
            begin
             s:=UpperCase(http.Headers[i]);
              if pos('CONTENT-LENGTH:',s)>0 then
              TotalBytes :=
StrToIntDef(copy(s,pos(':',s)+1,length(s)),0);
              end;
          http.Headers.Clear;

         end;
      // Try to get the file
      HTTPGetResult:=http.HTTPMethod('GET', fURL);
      while (HTTPGetResult=false) and (RetryAttempt<MaxRetries) do
      begin
        sleep(500*RetryAttempt);
        HTTPGetResult:=http.HTTPMethod('GET', fURL);
        RetryAttempt:=RetryAttempt+1;
      end;
      // If we have an answer from the server, check if the file
      // was sent to us.
      case http.Resultcode of
        100..299:
          begin
              Texthttp.LoadFromStream(http.document);
              ListHTTPFiles(Texthttp);
            with TFileStream.Create(fFileName,fmCreate or fmOpenWrite)
do
            try
              Seek(0, soFromBeginning);
              CopyFrom(http.Document, 0);
            finally
              Free;
              Texthttp.free;
            end;
            httpresult:=true;
          end; //informational, success
        300..399: begin
                  Texthttp.LoadFromStream(http.document);
 //                 RedirStr := HTTPGetResult.
                  httpresult:=false; //redirection. Not implemented,
but could be.
                  end;
        400..499: httpresult:=false; //client error; 404 not found etc
        500..599: httpresult:=false; //internal server error
        else httpresult:=false; //unknown code
      end;
    except
      // We don't care for the reason for this error; the download
failed.
      httpresult:=false;
    end;
  finally
    http.Free;
  end;
end; 
Friendly, J.P

----------------------------------------------------------------------
BigChimp · 2013-07-12 15:19

Hmmm, that code looks very familiar

----------------------------------------------------------------------
BeniBela · 2013-07-12 20:08

Everyone is always writing this so needless complicated.

With my Internet Tools, getting the absolute url of the first to an
exe on that page:

Code: [Select]uses simpleinternet;
var
  listingPage, absoluteUrlToFirstExe: String;
begin
  listingPage := 'http://get.videolan.org:81/vlc/last/win32/';
  absoluteUrlToFirstExe := process(listingPage, 'resolve-
uri(//a/@href[ends-with(., "exe")], "'+listingPage+'")').toString;
  showMessage(absoluteUrlToFirstExe);
end;

----------------------------------------------------------------------
mesiarm · 2013-07-12 20:56

Yes it is much faster and easier but it doesnt support Onstatus - for
progressbar to work....

----------------------------------------------------------------------
mesiarm · 2013-07-12 21:17

and Jurassic Pork ... I found it, but it is procedure in your case and
I don´t see how your code works...because with this code I will ask
server for directory index file... it will return it with Resultcode
200 and then change file to read? should´t it be sooner?

----------------------------------------------------------------------
BeniBela · 2013-07-12 22:10

Quote from: mesiarm on July 12, 2013, 10:56:41 pmbut it doesnt support
Onstatus - for progressbar to work....

Why would you want to show a progressbar while downloading the
directory listing?
That should be almost instantaneously.

Anyways:

Code: [Select]uses simpleinternet;
procedure tform.progress(sender: TObject; progress, maxprogress:
longint);
begin
  progressbar1.position := progress;
  progressbar1.max := maxprogress;
end;

procedure tform.download;
var
  listingPage, absoluteUrlToFirstExe: String;
begin
  needInternetAccess;
  defaultInternet.OnProgress:=@progress;
  listingPage := 'http://get.videolan.org:81/vlc/last/win32/';
  absoluteUrlToFirstExe := process(listingPage, 'resolve-
uri(//a/@href[ends-with(., "exe")], "'+listingPage+'")').toString;
  showMessage(absoluteUrlToFirstExe);
end;

on Windows at least.
(on Linux it does not work. More precise, on Linux progress is the
same value as synapse's THttpSend.DownloadSize, which seems to be not
what I expected it to be)

----------------------------------------------------------------------
Jurassic Pork · 2013-07-13 00:21

hello,

BeniBela : read the entire post . mesiarm wants to download a big file
but for this he wants to know the last name of the file ( with the
version in the name).

Mesiarm : Sorry    i show you a wrong way. Forget the ListHTTPFiles.
to do what you want :
1 - get the Filename of the last version of vlc
2 - get the Url from which the file will be downloaded.
3 - download the file

to do this a function to extract text from URL ( on 200 (OK) or 302
(redirect) result code )
Code: [Select]function GetTextFromURL(URL,regExpress: string): String;
var
  HTTPGetResult: Boolean;
  HTTPSender: THTTPSend;
  TextHttp : TStringList;
  x: integer;
  re: TRegExpr;
  s : string;
begin
  Result := '';
  HTTPSender := THTTPSend.Create;
  try
    HTTPGetResult := HTTPSender.HTTPMethod('GET', URL);
    if (HTTPSender.ResultCode = 200) or
       (HTTPSender.ResultCode = 302) then
     begin
       Texthttp := TStringList.Create();
       Texthttp.LoadFromStream(HTTPSender.Document);
       re := TRegExpr.Create;
       // expression to extract text from URL :
       re.Expression := regexpress;
       For x := 0 to Texthttp.Count -1  do
       begin
       s := Texthttp.Strings[x];
       if re.Exec(s) then Result := re.Match[1];
       end;
       re.Free;
       Texthttp.Free;
     end;
  finally
    HTTPSender.Free;
  end;
end;
code to download the file :
Code: [Select]procedure TForm1.Button1Click(Sender: TObject);
  var i:integer;
  URLtoDL,FileNameToDL:string;
  download: THTTPDownload;
begin
  FileNameToDL :=
GetTextFromURL('http://get.videolan.org:81/vlc/last/win32/',
                  '<li><a href=\"(.*\.exe)\".+');
  if FileNameToDL <> '' then
  begin
  URLtoDL :=
GetTextFromURL('http://get.videolan.org:81/vlc/last/win32/' +
             FileNameToDL,'<p>The document has moved <a
href=\"(.*\.exe)\".+');
  if URLtoDL <> '' then
    begin
     Updater.Progressbar1.Position := 0;
     download:= THTTPDownload.Create(URLtoDL, FileNameToDL);
     download.Resume;
     Updater.ShowModal;
     download.free;
    end;
  end;
end;
if you want more simple, use the great benibela's internet tools 
 (GPL)
here : http://benibela.de/sources_en.html#internettools

Friendly, J.P

----------------------------------------------------------------------
mesiarm · 2013-07-14 09:37

Jurrasic Pork thank you very much for your patience with me and for
your advices   and  BeniBela also thank you   And please look at this
image - it ´s preview of my project - 
http://img199.imageshack.us/img199/5716/ddyb.png Acessing to form ....
in main form updater is global variable ... and I have also changed
Owner from nil to Application and Showmodal to Show and deleted
updater.Free line  but it didnt worked. Now I have added line : Code:
[Select]if assigned (self) then showmessage ('yes in form activate')
else showmessage ('no in form activate');    to Tupdater.Formactivate
and it returns yes... so in formactivate and other form methods it
works because I have changed updater to self.... But in thread I have
to call it as updater because thread is other class and there it
returns no (if I call Code: [Select]if assigned (updater) then
showmessage ('yes in thread') else showmessage ('no in thread');  and
even Code: [Select]  if fupdater = nil then showmessage ('yes nil')
else showmessage ('no nil');   returns yes nil in thread) Please help
me ...

----------------------------------------------------------------------
Jurassic Pork · 2013-07-14 15:11

hello mesiarm,
the best solution would be to put your whole project in attachment (if
it is possible) to see what is wrong.

Friendly, J.P

----------------------------------------------------------------------
mesiarm · 2013-07-28 12:56

Sorry I wasn´t online for long time but now I have created demo
project of my problem because I wanted to know where s the problem -
here it is : http://uploadir.com/uploads/l79yb6ji/downloads/new

----------------------------------------------------------------------
Jurassic Pork · 2013-07-28 15:46

Hello Mesiarm,
i don't know why you don't work with Form2 all the time and why you
use fupdater variable.

With those changes it seems that your project run :

1 - remove unit2 from the uses at the beginning of the unit1.
Code: [Select]interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
StdCtrls;
2 - replace your code by this code after  implementation :
Code: [Select]implementation
uses Unit2;  //  here is the trick
{$R *.lfm}

{ TForm1 }

procedure TForm1.btnClick(Sender: TObject);

begin
  Form2.showmodal;
  end;

end.
3 - in the unit2 replace all the occurences of Fupdater by Form2.

Friendly, J.P

----------------------------------------------------------------------
mesiarm · 2013-07-30 18:48

Yes than you... now it works.... and please can you explain me what´s
difference in using in interface and implementation part? Idon´t
understand that....

----------------------------------------------------------------------
Jurassic Pork · 2013-07-30 22:54

for example read this about circular unit references

----------------------------------------------------------------------
mesiarm · 2013-08-01 21:44

ok thanks   I have read it. now I want to implement cancel button and
I have downloadthread.terminate command in cancelonclick, but it won´t
cancel download... I have read that terminate only send instruction to
terminate and i didn´t found way to force terminate thread ...so i
wanted to add while not terminated loop.... debbugging I have found
that during download is still running this command:  Code:
[Select]HTTPGetResult:=http.HTTPMethod('GET', fURL); so i have added
Code: [Select]while not terminated do
HTTPGetResult:=http.HTTPMethod('GET', fURL); It didn´t worked... I
wanted to use something like Application.ProcessMessages and since I
can´t use this command inside thread I tried this code which i had
found
Code: [Select]  if MsgWaitForMultipleObjects(0, nil, FALSE, 10,
QS_ALLINPUT) = WAIT_OBJECT_0 then
    begin
      while PeekMessage(Msg, 0, 0, 0, PM_REMOVE) do
      begin
        TranslateMessage(Msg);
        DispatchMessage(Msg);
      end;
    end;    without success. What can I do with it?

----------------------------------------------------------------------
mesiarm · 2013-09-19 20:45

Hm I found it, with http.Abort.... but Jurrasic Pork you have earlier
gave me function GetTextFromURL and it worked till now...please look
at it...  now I don´t know, why it stopped working and although it
with redirect with code you have said to me, when it connect to
server, it will return 302 Moved Temporarily