[SOLVED] REST API Consuming Help needed

[Blestan]

HI guys im writing a lib to access Kraken.com tradind lib but i have problems with sha256 and sha512 functions to generate signing for the private functions ... can.you point me a good and consistent across languages hash lib? i tried. hash4pascal but cannot make it to work ... i need sha256 w/o key ..

thanks in advance

[Leledumbo]

You have several options:

• https://github.com/fundamentalslib/fundamentals5
• http://wiki.lazarus.freepascal.org/DCPcrypt
• http://www.wolfgang-ehrhardt.de/crchash_en.html
• https://github.com/Xor-el/HashLib4Pascal

[Blestan]

according to the api docs the requests must be signned as follow

API-Key = API key
API-Sign = Message signature using HMAC-SHA512 of (URI path + SHA256(nonce + POST data)) and base64 decoded secret API key

here is my code but i still get error EAPI Invalid Key

Code: [Select]

function TKrakenAPI.QueryPrivate(const URI: string; Params: String): XVar;
var S: TMemoryStream;
    J: TJSONParser;

    URL,
    Sign,
    Sha256,
    Nonce: String;

    R,I,L: Integer;
    LHMAC: IHMAC;
    sha512: PChar;
    buf: array [00..64] of char;
begin

  Nonce:=IntToStr(DateTimeToUnix(Now));
  Params:='nonce='+nonce+'&'+params;
  sha256:=Nonce+Params;
  URL:=kraken_private+URI;
  L:=Length(URL);
  Getmem(sha512,L+32);
  Move(URL[1],Sha512^,L);

  with THashFactory.TCrypto.CreateSHA2_256().ComputeUntyped(sha256[1],Length(Sha256)) do
       move(getbytes[0],sha512[L],32);

  LHMAC:= THashFactory.THMAC.CreateHMAC(THashFactory.TCrypto.CreateSHA2_512);
  LHMAC.Key := TConverters.ConvertStringToBytes(DecodeStringBase64(FSecret), TEncoding.UTF8);


  // sign:=EncodeStringBase64(LHMAC.ComputeUntyped(sha512,L+32).ToString);

  move(LHMAC.ComputeUntyped(sha512,L+32).GetBytes[0],Buf[0],64);
  Buf[64]:=#0;
  sign:=EncodeStringBase64(Pchar(@Buf[0]));

  try
  FNET.AddHeader('API-Key:',FKEY);
  FNET.AddHeader('API-Sign:',Sign);
  FNET.AddHeader('Content-Type', 'application/x-www-form-urlencoded');
  FNET.AddHeader('Content-Length', IntToStr(Length(Params)));
   writeln(Nonce);
   writeln(URL);
   writeln(sha512);
   writeln(sign);


   S:=TMemoryStream.Create;
   J:=TJSONParser.Create;
   FNet.FormPOST(KrakenURL+URL,Params,S);
   R:=J.Parse(S.Memory,S.Size);
   writeln(R);
   if R>0 then Result:=J.UseXON
          else Result:=XVar.Null;

   with Result['result'] do
    for i:=0 to Count-1 do writeln(Keys[i].AsString,'=',Vars[i].AsString);
  finally
    J.Free;
    S.Free;
  end;
end;                           


[Blestan]

problem solved! )

if someone is interested in kraken.com API access from fpc feel free to contact me

[william22]

Dear Blestan,

Could you please share your code?
I'm having throuble posting the private functions.