Json fragment (tech)

Un fragment JSon est un élément d'un document JSon qui peut être manipulé comme une variable.

Exemple :

//Procedure TestJson;
var json:TJSon; va,v1,v2:variant;
begin
  json := TJson.Create(
  '{"a":[{"e1":1,"e2":2,"e3":{"e31":"v31","e32":["e321","e322"]}}]}'
  );
  va := json.a[0];
  v1 := json.a[0].e1; 
  v2 := va.e1;
  if v1<>v2 
   then showMessage('failed')
   else showMessage('Ok'); 
end;

Type de données

Type de donnée	Usage
variant	Tout fragment
TjsonStruct	Structure
TjsonArray	Tableau

Opération sur un fragment

op1	op2	ope	rslt
j1={a:0}	j2={b:0}	j1.assign(j2)	j1=={b:0}
j1={a:0}	j2={b:0}	j1.merge(j2)	j1==[{a:0},{b:0}]
j1={s:{a:0}}	j2={s:{b:0}}	j1.s.assign(j2.s)	j1=={s:{b:0}}
j1={s:{a:0}}	j2={s:{b:0}}	j1.s.merge(j2.s)	j1=={s:{a:0,b:0}}
j1={a:0}	j2={s:{b:0}}	j1.assign(j2.s)	j1=={b:0}
j1={a:0}	j2={s:{b:0}}	j1.merge(j2.s)	j1=={a:0,b:0}

AddStruct

var json1,json2:TJSon; vs,v1,v2:variant;
begin
  json1 := TJson.Create('{}');
  json1.AddStruct('b').c := 1;
 
  v1 := json1.b.c; 
  if v1=1 
   then showMessage('ok')
   else showMessage('failed'); 
end;

//Procedure TestJson1;
var json1,json2:TJson;
begin
  json1 := Tjson.Create('{}'); 
  json1.meta.id := 1;
 
  json2 := TJson.Create('{}');
  json2.bp.name := 'name';
  json2.bp.version := '1';
  json2.bp.addStruct('data','{...}');
  showMessage(json2.AsString);
 
  json1.meta.addStruct('bp',json2.bp);
  showMessage(json1.AsString);
  json1.CopyToClipboard;  
end;

Clear (tableau)

//Procedure TestJson4;
var json:TJSon; va,v1:variant;
begin
  json := TJson.Create('{}');
  json.b[0].a[0].Values := '1';
  va := json.b[0].a; 
  va.Clear(0);
 
  if va.count=0 
   then showMessage('ok')
   else showMessage('failed'); 
end;

Assign

//Procedure TestJSon8;
var json1,json2:TJSon; vb,v1:variant;
begin
  json1 := TJson.Create('{}');
  json1.a.b := 1;
  json1.a.AddStruct('b','{c:1}');
 
  vb := json1.a.b; 
  if not vb.Exists('c') then 
   begin 
     showMessage('failed'); 
     Exit;
   end; 
 
  v1 := vb.c; 
  if (v1<>1) then 
   begin 
     showMessage('failed'); 
     Exit;
   end; 
 
  // replace content of b 
  vb.Assign('{d:2}');
 
  if vb.Exists('c') then 
   begin 
     showMessage('failed'); 
     Exit;
   end; 
 
  if not vb.Exists('d') then 
   begin 
     showMessage('failed'); 
     Exit;
   end; 
 
  v1 := vb.d; 
  if (v1=2)
   then showMessage('ok')
   else showMessage('failed'); 
end;

Merge

//Procedure TestJson9;
var json1,json2:TJSon; vs,v1,v2:variant;
begin
  json1 := TJson.Create('{}');
  json1.a.b.x := 1;
  json1.a.b.Merge('{c:1}');
 
  v1 := json1.a.b.c; 
  if v1=1 
   then showMessage('ok')
   else showMessage('failed'); 
end;

//Procedure TestJson9;
var json1,json2:TJSon; vx,v1,v2:variant;
begin
  json1 := TJson.Create('{}');
  json1.a.b.c := 1;
  v1 := json1.a.b; 
  if not v1.Exists('c') then
   begin
     showMessage('failed (1)');
     Exit; 
   end; 
 
  json2 := TJson.Create('{}');
  json2.a.b.d := 1;
  v2 := json2.a.b;
  if not v2.Exists('d') then
   begin
     showMessage('failed (2)');
     Exit; 
   end; 
 
  v1.merge(v2); 
 
  if not v1.Exists('d') then
   begin
     showMessage('failed (3)');
     Exit; 
   end; 
 
  vx := json1.a.b.d; 
  if vx=1 
   then showMessage('ok')
   else showMessage('failed (2)'); 
end;