Exception in SynMustache using nested expression helpers

EMartin · 2017-01-23 20:17:46

Hi @ab, I try using nested expression helpers and I get an exception when last expression helper finalize. I can reproduce the issue with a modified version of sample "23 - Javascript Tests".

https://drive.google.com/file/d/0Bx7LPc … sp=sharing

Can you see the problem ? I need use this feature.

Thanks in advance.

Esteban.

EMartin · 2017-01-25 14:57:48

I cannot solve the problem yet, but I found a strange behavior. I changed the function FromBase64 and ToBase64.

...
class procedure TMainForm.FromBase64(const Value: variant; out result: variant);
var
  lValue, lResp: RawByteString;
begin
  VariantToRawByteString(Value, lValue);
  lResp := SynCommons.Base64ToBin(lValue);
  RawByteStringToVariant(lResp, result);
end;
...
class procedure TMainForm.ToBase64(const Value: variant; out result: variant);
var
  lValue, lResp: RawByteString;
begin
  VariantToRawByteString(Value, lValue);
  lResp := SynCommons.BinToBase64(lValue);
  RawByteStringToVariant(lResp, result);
end;

but the error continue, if I hardcoded in ToBase64 the result variable this works

...
class procedure TMainForm.FromBase64(const Value: variant; out result: variant);
var
  lValue, lResp: RawByteString;
begin
  VariantToRawByteString(Value, lValue);
  lResp := SynCommons.Base64ToBin(lValue);
  RawByteStringToVariant(lResp, result);
end;
...
class procedure TMainForm.ToBase64(const Value: variant; out result: variant);
var
  lValue, lResp: RawByteString;
begin
  VariantToRawByteString(Value, lValue);
  lResp := SynCommons.BinToBase64(lValue);
//  RawByteStringToVariant(lResp, result);
  result := 'dGV4dCBlbmNvZGVkIHdpdGggYmFzZTY0IHVzaW5nIGJpbnRvYmFzZTY0IGZ1bmN0aW9u';
end;

or if I hardcode the lValue variable in FromBase64, too this works

...
class procedure TMainForm.FromBase64(const Value: variant; out result: variant);
var
  lValue, lResp: RawByteString;
begin
  lValue := 'dGV4dCBlbmNvZGVkIHdpdGggYmFzZTY0IHVzaW5nIGJpbnRvYmFzZTY0IGZ1bmN0aW9u';
//  VariantToRawByteString(Value, lValue);
  lResp := SynCommons.Base64ToBin(lValue);
  RawByteStringToVariant(lResp, result);
end;
...
class procedure TMainForm.ToBase64(const Value: variant; out result: variant);
var
  lValue, lResp: RawByteString;
begin
  VariantToRawByteString(Value, lValue);
  lResp := SynCommons.BinToBase64(lValue);
  RawByteStringToVariant(lResp, result);
end;

I am very confused.

Any help is appreciated.

Esteban.

EMartin · 2017-01-25 15:00:42

I forgot to mention, in Delphi XE 10.1 Berlin the exception "Invalid Pointer Operation" is raised, in Delphi 7 the application it freezes.

Thanks.

Esteban.

ab · 2017-01-25 16:11:37

Because VariantToRawByteString are not true text variants which are compatible with JSON and mustache, but some custom variant types to be used internally for data transfert.

EMartin · 2017-01-25 16:47:43

Ok, but in the sample application I am not using VariantToRawByteString, but direct use of Base64ToBin and BinToBase64.

EMartin · 2017-01-25 20:16:13

I found a solution, is not the better but works for me, I made a copy of "const Value: variant" param and I work with that copy.

class procedure TMainForm.FromBase64(const Value: variant; out result: variant);
var
  lValue: RawByteString;
begin
  lValue := Copy(Value, 1, Length(Value));
  result := SynCommons.Base64ToBin(lValue);
end;

class procedure TMainForm.ToBase64(const Value: variant; out result: variant);
var
  lValue: RawByteString;
begin
  lValue := Copy(Value, 1, Length(Value));
  result := SynCommons.BinToBase64(lValue);
end;

@ab, is there a better solution ?

Thanks.

Esteban

EMartin · 2017-01-27 11:31:50

Just for curiosity, is not this a bug ? I mean, the sample application fail but with this patch no.

Esteban.

mORMot Open Source

#1 2017-01-23 20:17:46

Exception in SynMustache using nested expression helpers

#2 2017-01-25 14:57:48

Re: Exception in SynMustache using nested expression helpers

#3 2017-01-25 15:00:42

Re: Exception in SynMustache using nested expression helpers

#4 2017-01-25 16:11:37

Re: Exception in SynMustache using nested expression helpers

#5 2017-01-25 16:47:43

Re: Exception in SynMustache using nested expression helpers

#6 2017-01-25 20:16:13

Re: Exception in SynMustache using nested expression helpers

#7 2017-01-27 11:31:50

Re: Exception in SynMustache using nested expression helpers

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