myJSON

JSON parser for delphi 7 and earlier (and maybe even later)

Types:

myJSONItem - JSON node
myJDType - type of node (Object/Array/Value)
myJVType - value's subtype (Text/Number/Boolean)

myJSONItem

properties

Name: string - Node name (read only)
Item[name]: myJSONItem - Sub-item with specified name (read only, default property). Creates an item if it doesn't exist yet.
Code: string - Encoded JSON of this node and all of it's child nodes. Assign encoded JSON to this property to parse it.
Key[index]: string - Names of this node's children (won't work for arrays)
Value[index]: myJSONItem - Values of this node's child
Has[name]: boolean - returns true if node has a child with specified name

methods

Count: integer - Returns count of child nodes (works for both arrays and objects)
Remove(n) - Removes N-th child
LoadFromFile / SaveToFile - Obviously
Clear - Removes all child nodes, won't work on leaf nodes
setArray(newLength: integer) - Explicitly sets type to dtArray and allocates the memory

getters and setters:

All values are stored as strings, therefore there are number of getters to do all conversion for you. Each of this getters lets you to specify default values. Each setter will convert values to string.

getStr / setStr // string
getInt / setInt // integer
getNum / setNum // double (float)
getBool / setBool // boolean. True: 'true' or any number > 0. False: 'false' (or any other string, actually) or any number <= 0.

There are also methods for working with null-values

isNull: boolean - returns true if value is explicitly set to null
setNull - explicitly sets value to null

As it turned out assigning Code to Code works well for root elements, or when you assign root element's code to some child element. However, when you try to clone children this way, Code getter will return it with the leading "key":, and when the receiver will parse it, it'll see "key" and treat it as if it was a text value. Therefore I added (there were other options though) a method for reading value as an encoded JSON string

getJSON: string - returns value as an encoded JSON string (without adding key to it even if there is one)

Example 1: Reading values

conf.json

{
  "window": {
    "width": 400,
    "height": 300
   },
   "fonts": [
     "Arial",
     "Tahoma"
   ]
}

test1.pas

...
config := myJSONItem.Create;
list := TStringList.Create;
...
config.LoadFromFile('conf.json');
wnd.Width := config['window']['width'].getInt(DEFAULT_WIDTH);
for i := 0 to config['fonts'].Count - 1 do
  list.Add(config['fonts'].Value[i].getStr);
...
config.Free;

Example 2: Assigning values

...
a := myJSONItem.Create;
b := myJSONItem.Create;

a.Code := '{"item1":"value 1","item2":[3,4,5]}';
a['item3'].setStr('value 3');
Writeln(a.Code); // {"item1":"value 1","item2":[3,4,5],"item3":"value 3"}
b['desc'].setStr('And now for something completelly different');
b['c'].Code := a.Code;
Writeln(b.Code); // {"desc":"And now for something completelly different","c":{"item1":"value 1","item2":[3,4,5],"item3":"value 3"}}

telmedola/myJSON