Uniface User Forum

 View Only
  • 1.  WINAPI Interface for base64

    Posted 07-01-2022 03:33
    We're using U9.2 - before $encode/$decode were implemented & we'd like to decode base64 we're receiving.

    Tried to use the cryptBinaryToStringA operation in the crypt32.dll but not sure how to define the parameters: a couple are 'pointers'.
    Presumably we also have to specify the dll in the asn file?

    Can anybody help?

    Crypt32.dll Wincrypt.h
    C++ function to convert an array of bytes into a formatted string.
    If the function succeeds, the function returns nonzero (TRUE).
    If the function fails, it returns zero (FALSE).

    BOOL CryptBinaryToStringA(
    [in] const BYTE *pbBinary, Pointer to the array of bytes to be converted into a string.
    [in] DWORD cbBinary, Number of elements in the pbBinary array.
    [in] DWORD dwFlags, Format of the resulting formatted string.
    [out, optional] LPSTR pszString,
    [in, out] DWORD *pcchString);

    R W
    Hargreaves Lansdown Asset Mgmt
    Bristol GB

  • 2.  RE: WINAPI Interface for base64

    Posted 07-07-2022 09:07
    Are sure that the CryptBinaryToStringA function is decoding data? If I read it correctly then it is encoding or converting data to a formatted string (like e.g. Base64). I think you would need CryptStringToBinaryA to decode Base64.

    Anyway, looking at the interface definition I don't think that there is a straight forward way to call the mentioned function with a C Call-Out signature. I have never tried to call a parameter that is a pointer to an array of bytes. I know there is a way to handle a pointer to a string, but that is different (AFAIK).

    But why not use a default Windows command line tool that can do this, and call it from Uniface (with e.g. the Operating System Commands signature)? If I understand it correctly then the Certutil.exe can decode Base64 data. See (e.g.):
    I hope this helps.

    Daniel Iseli
    Principal Technical Support Engineer
    Uniface Services
    Rocket Software, Switzerland

  • 3.  RE: WINAPI Interface for base64

    Posted 08-24-2022 02:25
    Nope, I wasn't sure. 
    Gave up with trying a callout to WINAPI.

    Peter Lammersma suggested trying certUtil - and it worked!

    Just noticed that another component uses xmlsave/xmlload to perform the conversion...but didn't try it for the new instance as certUtil works fine.

    R W
    Hargreaves Lansdown Asset Mgmt
    Bristol GB