DelphiXe10 Json解析类(SuperObject)

# SuperObject ## What is JSON ? - JSON (JavaScript Object Notation) is a lightweight data-interchange format. - It is easy for humans to read and write. - It is easy for machines to parse and generate. - It is based on a subset of the JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999. - JSON is a text format that is completely language independent but uses conventions that are familiar to programmers. - These properties make JSON an ideal data-interchange language. - You can get more informations on [json.org](http://www.json.org). ```js { "name": "Jon Snow", /* this is a comment */ "dead": true, "telephones": ["000000000", "111111111111"], "age": 33, "size": 1.83, "adresses": [ { "adress": "foo", "city": "The wall", "pc": 57000 }, { "adress": "foo", "city": "Winterfell", "pc": 44000 } ] } ``` ## Parsing a JSON data structure ```pas var obj: ISuperObject; begin obj := SO('{"foo": true}'); obj := TSuperObject.ParseString('{"foo": true}'); obj := TSuperObject.ParseStream(stream); obj := TSuperObject.ParseFile(FileName); end; ``` ## Accessing data There isn't individual datastructure for each supported data types. They are all an object: the ISuperObject. ```pas val := obj.AsString; val := obj.AsInteger; val := obj.AsBoolean; val := obj.AsDouble; val := obj.AsArray; val := obj.AsObject; val := obj.AsMethod; ``` ## How to read a property value of an object ? ```pas val := obj.AsObject.S['foo']; // get a string val := obj.AsObject.I['foo']; // get an Int64 val := obj.AsObject.B['foo']; // get a Boolean val := obj.AsObject.D['foo']; // get a Double val := obj.AsObject.O['foo']; // get an Object (default) val := obj.AsObject.M['foo']; // get a Method val := obj.AsObject.N['foo']; // get a null object ``` ## How to read a value from an array ? ```pas // the advanced way val := obj.AsArray.S[0]; // get a string val := obj.AsArray.I[0]; // get an Int64 val := obj.AsArray.B[0]; // get a Boolean val := obj.AsArray.D[0]; // get a Double val := obj.AsArray.O[0]; // get an Object (default) val := obj.AsArray.M[0]; // get a Method val := obj.AsArray.N[0]; // get a null object ``` ## Using paths Using paths is a very productive method to find an object when you know where is it. This is some usage cases: ```pas obj['foo']; // get a property obj['123']; // get an item array obj['foo.list']; // get a property from an object obj['foo[123]']; // get an item array from an object obj['foo(1,2,3)']; // call a method obj['foo[]'] := value; // add an item array ``` you also can encapsulate paths: ```pas obj := so('{"index": 1, "items": ["item 1", "item 2", "item 3"]}'); obj['items[index]'] // return "item 2" ``` or recreate a new data structure from another: ```pas obj := so('{"index": 1, "items": ["item 1", "item 2", "item 3"]}'); obj['{"item": items[index], "index": index}'] // return {"item": "item 2", "index": 1} ``` ## Browsing data structure ### Using Delphi enumerator. Using Delphi enumerator you can browse item's array or property's object value in the same maner. ```pas var item: ISuperObject; begin for item in obj['items'] do ... ``` you can also browse the keys and values of an object like this: ```pas var item: TSuperAvlEntry; begin for item in obj.AsObject do ... begin item.Name; item.Value; end; ``` ### Browsing object properties without enumerator ```pas var item: TSuperObjectIter; begin if ObjectFindFirst(obj, item) then repeat item.key; item.val; until not ObjectFindNext(item); ObjectFindClose(item); ``` ### Browsing array items without enumerator ```pas var item: Integer; begin for item := 0 to obj.AsArray.Length - 1 do obj.AsArray[item] ``` ## RTTI & marshalling in Delphi 2010 ```pas type TData = record str: string; int: Integer; bool: Boolean; flt: Double; end; var ctx: TSuperRttiContext; data: TData; obj: ISuperObject; begin ctx := TSuperRttiContext.Create; try data := ctx.AsType<TData>(SO('{str: "foo", int: 123, bool: true, flt: 1.23}')); obj := ctx.AsJson<TData>(data); finally ctx.Free; end; end; ``` ## Saving data ```pas obj.AsJSon(options); obj.SaveTo(stream); obj.SaveTo(filename); ``` ## Helpers ```pas SO(['prop1', true, 'prop2', 123]); // return an object {"prop1": true, "prop2": 123} SA([true, 123]); // return an array [true, 123] ``` ## Non canonical forms The SuperObject is able to parse non canonical forms. ```pas // unquoted identifiers SO('{foo: true}'); // unescaped or unquoted strings SO('{собственность: bla bla bla}'); // excadecimal SO('{foo: \xFF}'); ```