[fpc-pascal] Null values with JSON RPC

[Michael Van Canneyt]

On Fri, 7 Aug 2020, Ryan Joseph via fpc-pascal wrote:

>
>
>> On Aug 7, 2020, at 8:31 PM, Michael Van Canneyt <michael at freepascal.org> wrote:
>> 
>> An option to allow nulls to be detected and handles would of course be a nice
>> addition.
>> 
>> For the time being, you can just set jdoIgnorePropertyErrors on the destreamer options.
>
> Quick check right now and setting that option still seems to give the same
> error.  I'll look into it more tomorrow when I have some time.  There's
> seems to be a DoRestoreProperty override which could be interesting but
> I'm not sure if the error is trigger before here or not.

try
     B:=Not Assigned(FOnRestoreProp);
     If Not B then
       begin
       FOnRestoreProp(Self,AObject,PropInfo,PropData,B);
       If B then
         exit;
       end;
     DoRestoreProperty(AObject,PropInfo,PropData);
   except
     On E : Exception do
       If Assigned(FOnPropError) then
         begin
         B:=False;
         FOnPropError(Self,AObject,PropInfo,PropData,E,B);
         If Not B then
           Raise;
         end
       else if Not (jdoIgnorePropertyErrors in Options) then
         Raise;
   end;

The exception will still be raised, but should be caught.

I added a jdoIgnoreNulls which changes the above to:

   if (PropData.JSONType=jtNull) then
       if Not (jdoIgnoreNulls in Options) then
         DoRestoreProperty(AObject,PropInfo,PropData);

Committed in SVN. I will still add a jsoNullClearsProperty which will clear
the property using the 'natural' empty value (0, Nil, '' etc).

Michael.