[SOLVED] Process JSON structure

[tudi_x]

hi All,
i received a JSON format to extract the info from it (simplified structure below). it is not defined as an array although it has more than one object.
please advise what would be the best way to parse it with standard library (fpjson, jsonparser, jsonscanner).
thank you

Code: Pascal  [Select][+][-]

1. {"A":{"field1":0, "field2": false},"B":{"field1":0, "field2": false}}

[balazsszekely]

@tudi_x

If you go to LazMenu-->Tools-->Example Projects, you can find a project named "jsonviewer" with a generic parser(see attached image). You can feed your json and see what happens by debugging.

[tudi_x]

with all due respect GetMem i say we delete the wiki and point the users to the code.

[balazsszekely]

@tudi_x

with all due respect GetMem i say we delete the wiki and point the users to the code.

I'm not sure what you mean. Which wikipage are you referring to?

Just an idea to get started. I'm almost certain you can achieve the same thing with other methods too.

Code: Pascal  [Select][+][-]

1. uses fpjson, jsonparser;
2.  
3. procedure TForm1.Button1Click(Sender: TObject);
4. var
5.   Parser: TJSONParser;
6.   Data: TJSONData;
7.   JSON: TJSONStringType;
8.   I: Integer;
9.   DataName, ObjName, ObjValue: String;
10. begin
11.   JSON := '{"A":{"present":0},"B":{"present":1}}';
12.   Parser := TJSONParser.Create(JSON);
13.   try
14.     Data := Parser.Parse;
15.     try
16.       if Data.JSONType = jtObject then
17.       begin
18.         for I := 0 to Data.Count - 1 do
19.         begin
20.           if Data.Items[I].JSONType = jtObject then
21.           begin
22.             DataName := TJSONObject(Data).Names[I];
23.             ObjName := TJSONObject(Data.Items[I]).Names[0];
24.             ObjValue := TJSONObject(Data.Items[I]).Get(ObjName);
25.             ShowMessage(DataName + sLineBreak + '   ' + ObjName + sLineBreak + '        ' + ObjValue);
26.           end;
27.         end;
28.       end;
29.     finally
30.       Data.Free;
31.     end;
32.   finally
33.     Parser.Free;
34.   end;
35. end;

[tudi_x]

thank you
the below worked for me:

Code: Pascal  [Select][+][-]

1. procedure TForm1.DecodeString(AJSON: string);
2. var
3.   jsData: TJSONData;
4.   jsItem: TJSONData;
5.   i, j: word;
6.   object_name, field_name, field_value, object_type, object_items: string;
7.  
8. begin
9.   try
10.     jsData := GetJSON(AJSON);
11.  
12.     for i := 0 to jsData.Count - 1 do
13.     begin
14.       jsItem := jsData.Items[i];
15.  
16.       object_type := GetEnumName(TypeInfo(TJSONtype), Ord(jsItem.JSONType));
17.       object_name := TJSONObject(jsData).Names[i];
18.       object_items := IntToStr(jsItem.Count);
19.  
20.       memo1.Append('object type: ' + object_type + '|object name: ' + object_name + '|number of fields: ' + object_items);
21.  
22.       for j := 0 to jsItem.Count - 1 do
23.       begin
24.         field_name := TJSONObject(jsItem).Names[j];
25.         field_value := jsItem.FindPath(TJSONObject(jsItem).Names[j]).AsString;
26.  
27.         memo1.Append(field_name + '|' + field_value);
28.       end;
29.     end;
30.  
31.   finally
32.     FreeAndNil(jsData);
33.   end;
34. end;    

[tudi_x]

i updated the wiki in http://wiki.freepascal.org/JSON#JSON_Object with a link to this code.
thank you!

[balazsszekely]

i updated the wiki in http://wiki.freepascal.org/JSON#JSON_Object with a link to this code.

Thanks @tudi_x.