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Author Topic: What Web and Crypto components to use for Online Invoiceing REST API?  (Read 2820 times)

MrSteering

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  • Posts: 3
Hi Guys,

Pascal programming is my hobby. I should add an extension to my old program, what I already succesfully migrated from Delphi 7 to Lazarus... :)

The add-on is needed for the Hungarian NAV Online Invoice System REST API v3.0: https://onlineszamla.nav.gov.hu/api/files/container/download/Online%20Invoice%20System%203.0%20Interface%20Specification.pdf

I am newbie in web programming and encrypting, and need a bit of kickstarting help :o
I need to send, retrieve xml files and make encrypting. I would like to use as many stable/maintained and free components as possible, even if it is more work.
Specified encoding/decoding standard needs for the API:
- BASE64 encode/decode (RFC3548)
- SHA-512 encode (RFC6234)
- SHA3-512 encode (FIPS 202)
- AES-128 ECB decode (RFC3826)

Here is an example TokenExchange code I found (with commercial components), which illlustrates the needs of the REST API: https://example-code.com/delphiDll/nav_token_exchange.asp

I think I will need:
- fpWeb (TFPHTTPClient)
- CryptoLib4Pascal (as I saw it supports all)
- xml (I am using TXMLDocument already - did not find good xml binding support)

Can you please support me with some inputs on the components/packages I should use?
It would be great to have a code example based on the linked example using your proposed components/packages!

THANK YOU VERY MUCH!

Thaddy

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Re: What Web and Crypto components to use for Online Invoiceing REST API?
« Reply #1 on: January 31, 2022, 09:32:54 pm »
The best crypto lib is by Xor-El So you are on the right way ;)
https://github.com/Xor-el/CryptoLib4Pascal
Black themes should be banned.

engkin

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Re: What Web and Crypto components to use for Online Invoiceing REST API?
« Reply #2 on: February 01, 2022, 04:50:10 am »
I agree with Thaddy. You seem to have found all the right packages.

Page 16 of the pdf file has an example for calculating the signatue of the request. Here is a quick test:
Code: Pascal  [Select][+][-]
  1. program project1;
  2.  
  3. {$mode objfpc}{$H+}
  4.  
  5. uses
  6.   {$IFDEF UNIX}
  7.   cthreads,
  8.   {$ENDIF}
  9.   Classes
  10.   ,SysUtils
  11.   ,ClpDigestUtilities
  12.   ,ClpIDigest
  13.   ,ClpCryptoLibTypes
  14.   ,ClpConverters
  15.  
  16.   ,ClpEncoders
  17.  
  18.   ,RegExpr
  19.  
  20.   { you can add units after this };
  21.  
  22. function Timestamp2Str(const ATimestamp:string):string;
  23. var
  24.   re:TRegExpr;
  25. begin
  26.   re:=TRegExpr.Create;
  27.   try
  28.     re.Expression:='(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})(.\d{1,3})?Z';
  29.     re.InputString:=ATimestamp;
  30.     if re.Exec then
  31.       Result:=re.Match[1]+re.Match[2]+re.Match[3]+re.Match[4]+re.Match[5]+re.Match[6]
  32.     else
  33.       Result:='';
  34.   finally
  35.     re.Free;
  36.   end;
  37. end;
  38.  
  39. function SHA3_512(AInput:String):String;
  40. var
  41.   LDigest:IDigest;
  42.   LInputBytes:TCryptoLibByteArray;
  43.   LOutputBytes:TCryptoLibByteArray=();
  44. begin
  45.   LDigest:=TDigestUtilities.GetDigest('SHA3-512');
  46.   LInputBytes := TConverters.ConvertStringToBytes(AInput, TEncoding.UTF8);
  47.   LDigest.BlockUpdate(LInputBytes, 0, Length(LInputBytes));
  48.   SetLength(LOutputBytes,LDigest.GetDigestSize);
  49.   LDigest.DoFinal(LOutputBytes, 0);
  50.   Result:=TConverters.ConvertBytesToHexString(LOutputBytes,False);
  51. end;
  52.  
  53. function invoiceHash(const AMsg:string; const invoiceOperation: string; const invoiceData:string):string;
  54. var
  55.   hash_base:string;
  56.   hash_upper:string;
  57. begin
  58.   WriteLn(AMsg);
  59.   hash_base:=invoiceOperation+invoiceData;
  60.   WriteLn('hash_base: ',hash_base);
  61.   hash_upper:=SHA3_512(hash_base);
  62.   WriteLn('hash_upper: ',hash_upper);
  63.   WriteLn;
  64.   Result:=hash_upper;
  65. end;
  66.  
  67. var
  68.   requestId:string = 'TSTKFT1222564';
  69.   timestamp:string = '2017-12-30T18:25:45.000Z';
  70.   {technical user’s signature }key:string = 'ce-8f5e-215119fa7dd621DLMRHRLH2S';
  71.  
  72.   //the index#1 invoice data items
  73.   invoiceOperation1:string = 'CREATE';
  74.   invoiceData1:string = 'QWJjZDEyMzQ=';
  75.  
  76.   //the index#2 invoice data items
  77.   invoiceOperation2:string = 'MODIFY';
  78.   invoiceData2:string = 'RGNiYTQzMjE=';
  79.  
  80.   partial_authentication_value:string;
  81.  
  82.   ih:array of string;
  83.   base_signature:string;
  84.   request_signature:string;
  85.   i: Integer;
  86. begin
  87.   ih:=[
  88.     invoiceHash('First:', invoiceOperation1, invoiceData1),
  89.     invoiceHash('Second:', invoiceOperation2, invoiceData2)
  90.       ];
  91.  
  92.   partial_authentication_value:=requestId+Timestamp2Str(timestamp)+key;
  93.   WriteLn('partial authentication value');
  94.   WriteLn(partial_authentication_value);
  95.   WriteLn('');
  96.  
  97.   base_signature:=partial_authentication_value;
  98.   for i:=0 to High(ih) do
  99.     base_signature:=base_signature+ih[i];
  100.   SetLength(ih,0);
  101.  
  102.   WriteLn('base signature:');
  103.   WriteLn(base_signature);
  104.   WriteLn('');
  105.  
  106.   request_signature:=SHA3_512(base_signature);
  107.   WriteLn('request signature:');
  108.   WriteLn(request_signature);
  109.  
  110.   ReadLn;
  111. end.

MrSteering

  • Newbie
  • Posts: 3
Re: What Web and Crypto components to use for Online Invoiceing REST API?
« Reply #3 on: February 02, 2022, 04:25:16 pm »
Thanx a lot Guys!

I go for it than :)

MrSteering

  • Newbie
  • Posts: 3
Re: What Web and Crypto components to use for Online Invoiceing REST API?
« Reply #4 on: February 07, 2022, 01:22:35 am »
Let me ask for another shot.
Is there some documentation or good examples how to use TFPHttpClient for my needed operations:
- send requests xmls
- get response xmls
- post specific xmls
???

I think the xml handling I will be able to handle, however as earlier mentioned an xml binder would be great...

Thanx in advanced again.

 

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