Delphi 10, Digital Persona and MySQL - mysql

Question

I am at my wits end at the moment. I have looked everywhere for a way of verifying a captured fingerprint in my MySQL database using the Digital Persona SDK(One Touch) and Delphi 10. I am able to save the fingerprint as a longblob in my database but I am unable to verify from my database. Hopefully someone here would be able to assist me. Reader is a U.Are.U 4500.
Below is the code I use to save the fingerprint, but I have no idea how to query the database when I need to verify the fingerprint again.
procedure TForm1.FPCaptureComplete(ASender: TObject;
const ReaderSerNum: WideString; const pSample: IDispatch);
var
l_interface : IDispatch;
outFile : File;
vt : integer ;
vtByteBuf : PByteArray;
aryLow : integer;
aryHigh : integer;
rawDataSize: integer;
loopIndex : integer;
begin
l_interface := FPGetImage.ConvertToPicture(pSample);
lblInfo.Caption:='Sample Captured';
SetOlePicture(pbPrint.Picture,IPictureDisp(l_interface)); //display print
if breginprogress=true then begin
if index > 4 then index:=1; //reset index if beyond 4 presses
if index=1 then
begin
lbl1.Font.Color:=clGreen;
lbl2.Font.Color:=clYellow;
end;
if index=2 then
begin
lbl2.Font.Color:=clGreen;
lbl3.Font.Color:=clYellow;
end;
if index=3 then
begin
lbl3.Font.Color:=clGreen;
lbl4.Font.Color:=clYellow;
end;
if index=4 then lbl4.Font.Color:=clGreen;
index := index + 1;
//Create registration\enrollment featureset from sample captured
try
FPExtraction.CreateFeatureSet(pSample,DataPurposeEnrollment);
except
on E: Exception do begin
showmessage('Exception inside CreateFeatureSet');
showmessage(E.Message);
FPregister.Clear;
ResetLabels;
index:=1;
exit;
end;
end;
if FPExtraction.FeatureSet <> nil then
//Add features to registration object
FPRegister.AddFeatures(FPExtraction.FeatureSet)
else begin
Showmessage('Could not create featureset, poor press');
FPRegister.Clear;
ResetLabels;
index:=1;
exit; //return
end;
//If 4 successful features added, status should be 'Ready'
if FPRegister.TemplateStatus=TemplateStatusTemplateReady then begin
lblResult.Caption:='User Enrolled - Press Finger for Verification';
lbl1.Visible:=false; lbl2.Visible:=false; lbl3.Visible:=false; lbl4.Visible:=false;
FPTemplate:=FPRegister.Template as DPFPShrXLib_TLB.DPFPTemplate;
breginprogress:=false; //stop registration process, enable verification
//Before saving data to database you will need to get the raw data (variant)
try
vrnt:=FPTemplate.Serialize; //raw data is now stored in this variant
aryLow:=VarArrayLowBound(vrnt,1);
aryHigh:=varArrayHighBound(vrnt,1);
aryHigh:=aryHigh-aryLow;
vtByteBuf:=VarArrayLock(vrnt); //lock down the array
for loopIndex := 0 to aryHigh - 1 do
fpData[loopIndex]:=vtByteBuf[loopIndex];
VarArrayUnlock(vrnt);
//Save fpData to database here
//Database logic is not provided here. Plenty examples on web on
//How to save a byte array (binary data) to database.
SaveFP;
except
on E: Exception do showmessage('Trouble saving data');
end;
end;
end;
end;
//This is the pysical save
procedure TForm1.SaveFP;
var
tptStream: TMemoryStream;
p: Pointer;
begin
MemberTbl.Insert;
MemberTbl.FieldByName('MemberName').AsString := NameEdit.Text;
tptStream := TMemoryStream.Create();
tptStream.Position := 0;
p := VarArrayLock(vrnt);
tptStream.Write(p^, VarArrayHighBound(vrnt, 1));
VarArrayUnlock(vrnt);
(MemberTbl.FieldByName('MemberFP') as BlobField).LoadFromStream(tptStream);
MemberTbl.Post;
tptStream.Free();
end;

Answer 1

I've created a component wrapper for the DigitalPersona One Touch for Windows SDK Version 1.6.1 (August 2010)
I've tested it with the DigitalPersona U.are.U 4000B reader, but according to the documentation, it should work with the DigitalPersona U.are.U 4500 reader too
You can have a look and download the component here
Then you can add code like this on the OnCaptured event handler:
procedure TForm1.DPFingerPrintReader1Captured(Reader: TDPFingerPrintReader; FingerComparer: IFingerComparer);
var
LFingerPrintField: TField;
begin
LFingerPrintField := YourDataSet.FieldByName('FingerPrintField');
while not YourDataSet.Eof do
begin
if FingerComparer.CompareTo(LFingerPrintField.AsString) then
begin
ShowMessage('Found');
Exit;
end;
YourDataSet.Next;
end;
ShowMessage('NOT Found');
end;