There is an inconsistency of how SuperObject and TJson.ObjectToJsonObject represent certain parts of a class (i.e. Record fields). Let's have the following code snippet:
Uses rest.json, superobject;
type
TSimplePersonRec = record
FirstName: string;
LastName: string;
Age: byte;
end;
TSimplePerson = class
protected
FPersonRec: TSimplePersonRec;
public
property personRecord: TSimplePersonRec read FPersonRec write FPersonRec;
end;
// ...
{ Public declarations }
function toJson_SO(simplePerson: TSimplePerson): string;
function toJson_Delphi(simplePerson: TSimplePerson): string;
// ...
function TForm1.toJson_Delphi(simplePerson: TSimplePerson): string;
begin
result := tjson.Format(TJson.ObjectToJsonObject(simplePerson));
end;
function TForm1.toJson_SO(simplePerson: TSimplePerson): string;
var
so: ISuperObject;
ctx: TSuperRttiContext;
begin
ctx := TSuperRttiContext.Create;
try
so := ctx.AsJson<TSimplePerson>( simplePerson );
finally
ctx.Free;
end;
result := so.AsJSon(true, true);
end;
// ...
procedure TForm1.Button3Click(Sender: TObject);
var
spr: TSimplePersonRec;
sp: TSimplePerson;
begin
spr.FirstName := 'John';
spr.LastName := 'Doe';
spr.Age := 39;
sp := TSimplePerson.Create;
sp.personRecord := spr;
memo1.Lines.Add(#13'--- SuperObject ---'#13);
memo1.Lines.Add(toJson_SO(sp));
memo1.Lines.Add(#13'--- Delphi ---'#13);
memo1.Lines.Add(toJson_Delphi(sp));
end;
The OUTPUT is:
--- SuperObject ---
{
"FPersonRec": {
"LastName": "Doe",
"Age": 39,
"FirstName": "John"
}
}
--- Delphi ---
{
"personRec":
[
"John",
"Doe",
39
]
}
What's the reason for Delphi to represent records as JSON array? Is there a public standard or suggestion leading to this?
Note: For me it's more natural to represent records with {key: value} notation instead of array. Not knowing the key name to witch the value belongs may have strange results during deserialization. For Example during deserialization I could pass a new class with the same layout, containing a record with different memory layout. In this case the values will be randomly assigned or an AV could occur?
UPDATE: I'm using Delphi XE7. Also I found this of json.org:
JSON is built on two structures:
- A collection of name/value pairs. In various languages, this is realized as an object, record, struct, dictionary, hash table, keyed list, or associative array.
- An ordered list of values. In most languages, this is realized as an array, vector, list, or sequence.
So probably the question is more about is this a bug in TJson unit?
