[SOLVED] REST API Consuming Help needed
lazarus / 38-Networking and Web Programming

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Blestan · 2017-11-04 19:56

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

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Leledumbo · 2017-11-05 03:54

You have several options:
https://github.com/fundamentalslib/fundamentals5http://wiki.lazarus.fr
eepascal.org/DCPcrypthttp://www.wolfgang-
ehrhardt.de/crchash_en.htmlhttps://github.com/Xor-el/HashLib4Pascal

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Blestan · 2017-11-05 12:15

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;

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Blestan · 2017-11-05 14:58

problem solved! )

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

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william22 · 2018-10-08 09:57

Dear Blestan,

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