[SOLVED] httpsend, ssl_openssl  Download a file from
https://wow.curseforge.com
lazarus / 38-Networking and Web Programming

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TheLastCayen · 2018-09-26 12:52

Hi Everyone,

I am using
  Lazarus 1.8.4
  FPC Version 3.0.4
  Windows 7 64
  openssl-1.0.2j-x64_86-win64.zip
  synalist-code-r209-trunk

I am trying to download a file from https://wow.curseforge.com. The
site do a redirection instead of a direct download. For my example I
will use
https://wow.curseforge.com/projects/vuhdo/files/latest

Right now I am working with rvk code  from
http://forum.lazarus.freepascal.org/index.php?topic=30344.0 .

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.DownloadAddons(WebPage:string);var      HTTP: THTTPSend;     
Redirected: boolean;      Filename: String;      Line: string;      i,
j1, j2: integer;      DownloadAddon:string;    begin      Filename :=
'unknown';      DownloadAddon:=C:\Users\dbabin\Downloads\WOW\new\;   
 HTTP := THTTPSend.Create;      try        repeat          Redirected
:= False;          HTTP.HTTPMethod('GET', WebPage);          case
HTTP.Resultcode of            301, 302, 307:            begin        
    Memo1.Lines.LoadFromStream(HTTP.Document);              for i := 0
to HTTP.Headers.Count - 1 do                if (Pos('location: ',
lowercase(HTTP.Headers.Strings[i])) = 1) then                begin   
             WebPage := StringReplace(HTTP.Headers.Strings[i],
'location: ', '', []);                  HTTP.Clear;                 
Redirected := True;                  break;                end;      
    end;          end;        until not Redirected;         // extract
filename from headers        // content-disposition: attachment;
filename="zzzzzzz.zzz"; filename*=UTF-8''zzzzzz.zzz        for i := 0
to HTTP.Headers.Count - 1 do          if (Pos('content-disposition:
attachment;',            lowercase(HTTP.Headers.Strings[i])) = 1)
then          begin            Line := HTTP.Headers.Strings[i];      
    j1 := pos('filename="', Line);            if j1 > 0 then         
 begin              j1 := j1 + length('filename="');              j2
:= j1;              while (j2 < length(Line)) and (Line[j2] <> '"')
do                Inc(j2);              if j2 <= length(Line) then   
           Filename := Copy(Line, j1, j2 - j1);            end;      
  end;         HTTP.Document.SaveToFile(DownloadAddon + Filename);   
  finally        HTTP.Free;      end;      ShowMessage('Done');end;  
 
If I understand this code look for the header to get the file name and
download it. But instead my code create the empty unknown file. I am
assuming curseforge use a different way to send the file then Dropbox.
This is why I create a Memo1 and try to load the content of
HTTP.Document so I can modify the code. But memo1 stay empty.

Anyone know what I am doing wrong when I am trying to read the
HTTP.Document? Or there is a better way to download the file?

Thank you

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balazsszekely · 2018-09-27 04:32

QuoteAnyone know what I am doing wrong when I am trying to read the
HTTP.Document? Or there is a better way to download the file?
Please test attached project. You should change the values in
"Button1click" according to your needs.

PS: The code can be further optimized. If you are on windows and you
don't have the openssl dll's, the application will download it for
you, however there is no visual feedback for this. Also you should
create a new unit with a TDownload class, where all the download
related stuff is implemented. Now everything is in the main
unit...looks ugly.

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TheLastCayen · 2018-09-27 05:23

Oh wow, this is better than I was expecting.
Thank you Very much GetMem, I am really impressed with your quick
answer and the work you did. I tested it with few other site and it
works perfectly:)

Have a great day.