Parsing JSON for Ulugbek Nurjanov

.pas

program JSONParsingExample;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.SysUtils,
  System.Net.HttpClient,
  System.Generics.Collections,
  System.JSON;

type
  TValute = class(TObject)
    private
      FName: string;
      FNominal: Integer;
      FNumCode: string;
      FID: string;
      FCharCode: string;
      FPrevious: Single;
      FValue: Single;
      procedure SetCharCode(const Value: string);
      procedure SetID(const Value: string);
      procedure SetName(const Value: string);
      procedure SetNominal(const Value: Integer);
      procedure SetNumCode(const Value: string);
      procedure SetPrevious(const Value: Single);
      procedure SetValue(const Value: Single);
    public
      property ID : string read FID write SetID;
      property NumCode : string read FNumCode write SetNumCode;
      property CharCode : string read FCharCode write SetCharCode;
      property Nominal : Integer read FNominal write SetNominal;
      property Name : string read FName write SetName;
      property Value : Single read FValue write SetValue;
      property Previous : Single read FPrevious write SetPrevious;
  end;

  TSomeClass = class(TObject)
    private
      FDate: string;
      FPreviousDate: string;
      FPreviousURL: string;
      FTimeStamp: string;
    FValutes: TObjectlist<TValute>;
      procedure SetDate(const Value: string);
      procedure SetPreviousDate(const Value: string);
      procedure SetPreviousURL(const Value: string);
      procedure SetTimeStamp(const Value: string);
      procedure SetValutes(const Value: TObjectlist<TValute>);
    public
      constructor Create;
      destructor Destroy; override;
      property Date : string read FDate write SetDate;
      property PreviousDate : string read FPreviousDate write SetPreviousDate;
      property PreviousURL : string read FPreviousURL write SetPreviousURL;
      property TimeStamp : string read FTimeStamp write SetTimeStamp;
      //We threat Valutes as ObjectList (Cleaner)
      property Valutes : TObjectlist<TValute> read FValutes write SetValutes;
  end;

var
  httpresponse : IHTTPResponse;
  jsoncontent : string;


{ TSomeClass }

constructor TSomeClass.Create;
begin
  FValutes := TObjectList<TValute>.Create(True);
end;

destructor TSomeClass.Destroy;
begin
  FValutes.Free;
  inherited;
end;

procedure TSomeClass.SetDate(const Value: string);
begin
  FDate := Value;
end;

procedure TSomeClass.SetPreviousDate(const Value: string);
begin
  FPreviousDate := Value;
end;

procedure TSomeClass.SetPreviousURL(const Value: string);
begin
  FPreviousURL := Value;
end;

procedure TSomeClass.SetTimeStamp(const Value: string);
begin
  FTimeStamp := Value;
end;

procedure TSomeClass.SetValutes(const Value: TObjectlist<TValute>);
begin
  FValutes := Value;
end;

{ TValute }

procedure TValute.SetCharCode(const Value: string);
begin
  FCharCode := Value;
end;

procedure TValute.SetID(const Value: string);
begin
  FID := Value;
end;

procedure TValute.SetName(const Value: string);
begin
  FName := Value;
end;

procedure TValute.SetNominal(const Value: Integer);
begin
  FNominal := Value;
end;

procedure TValute.SetNumCode(const Value: string);
begin
  FNumCode := Value;
end;

procedure TValute.SetPrevious(const Value: Single);
begin
  FPrevious := Value;
end;

procedure TValute.SetValue(const Value: Single);
begin
  FValue := Value;
end;

function ParseValute(JSONObject : TJSONObject) : TArray<TValute>;
begin
  //TODO.
end;

function ParseJSONResponse(const aJSON : string) : TSomeClass;
var
  vJSONScenario : TJSONValue;
  vJSONPair : TJSONPair;
  a : TDateTime;
  x : Integer;
begin
  vJSONScenario := TJSONValue.Create;
  vJSONScenario := TJSONObject.ParseJSONValue(aJSON, False);
  if vJSONScenario = nil then raise Exception.Create('Invalid JSON string!')
  else if vJSONScenario is TJSONArray then raise Exception.Create('Passed JSON is an Array!');
  Result := TSomeClass.Create;
  for x := 0 to TJSONObject(vJSONScenario).Count - 1 do
  begin
    vJSONPair := TJSONObject(vJSONScenario).Pairs[x];
    if vJSONPair.JsonString.Value = 'Date' then Result.Date := TJSONObject(vJSONScenario).GetValue('Date').ToString.Replace('"','');
    if vJSONPair.JsonString.Value = 'PreviousDate' then Result.PreviousDate := TJSONObject(vJSONScenario).GetValue('PreviousDate').ToString.Replace('"','');
    if vJSONPair.JsonString.Value = 'PreviousURL' then Result.PreviousURL := TJSONObject(vJSONScenario).GetValue('PreviousURL').ToString.Replace('"','');
    if vJSONPair.JsonString.Value = 'Timestamp' then Result.TimeStamp := TJSONObject(vJSONScenario).GetValue('Timestamp').ToString.Replace('"','');
    if vJSONPair.JsonString.Value = 'Valute' then Result.Valutes.AddRange(ParseValute(vJSONScenario.GetValue('Valute') as TJSONObject));
  end;
end;

begin
  try
    { TODO -oUser -cConsole Main : Insert code here }
    with THTTPClient.Create do
    begin
      try
        httpresponse := Get('https://www.cbr-xml-daily.ru/daily_json.js');
        if httpresponse.ContentLength = 0 then raise Exception.Create('Empty response')
        else if httpresponse.HeaderValue['content-type'] <> 'application/javascript' then raise Exception.Create('Invalid content type... not a real JSON response');
        jsoncontent := httpresponse.ContentAsString();
      finally
        Free;
      end;
    end;
    // We need to parse response
    ParseJSONResponse(jsoncontent);

  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.