In the second tutorial of this series, we looked at parsing a JSON document and reading from an object. This tutorial will just extend do that.

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With json_SetIterator, not only can you loop through arrays but you can also loop through objects too, to get a key/value list. See this page to learn about iterators in noxDB.

We are using two new APIs here:

• json_GetName which returns a string of current items key.
• json_GetValue which returns a string of the current items value. You can also use one of the many json_Get* functions available, like json_GetStr, json_GetInt or json_GetBool.

Dcl-S  Document Pointer;
Dcl-S  name     Varchar(10);
Dcl-S  value    Varchar(40);
Dcl-DS list     likeds(JSON_ITERATOR);

Document = JSON_ParseString (
  '{                      '+
  '  a:123,               '+
  '  b:"text",            '+
  '  c:"More text"        '+
  '}'
);

list = json_SetIterator(Document);
dow json_ForEach(list);
  name  = json_GetName(list.this);
  value = json_GetValue(list.this);
enddo;

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Next, what if you have data which has objects within objects? Luckily list.this also allows you to access subnodes too.

You can use json_GetValuePtr to determine whether the current item in the list is a primitive value or an object.

Document = json_ParseString('{ a: 1, b : { c : 2 , d : 3 }}');

list = json_SetIterator(Document);
dow json_ForEach(list);
  name  = json_GetNameAsPath(list.this:'.');
  value = json_GetValue (list.this);

  //Check if item is an object.
  If (json_GetValuePtr(list.this:*Null) = *Null);
    Dsply (name + ' is an object');
    //Do work with list.this here.
  else;
    dsply (name + value);
  endif;

enddo;