unit PM.JSON;

interface

uses
  System.SysUtils, System.Classes, System.JSON, IdCustomHTTPServer;

type
  TJSONHelper = class
  public
    class function ReadBody(ARequest: TIdHTTPRequestInfo): TJSONObject;
    class procedure SendJSON(AResponse: TIdHTTPResponseInfo; AObj: TJSONValue;
      ACode: Integer = 200; AOwnsObj: Boolean = True);
    class procedure SendError(AResponse: TIdHTTPResponseInfo; ACode: Integer;
      const AMsg: string);
    class procedure SendOK(AResponse: TIdHTTPResponseInfo; const AMessage: string = 'OK');
  end;

implementation

class function TJSONHelper.ReadBody(ARequest: TIdHTTPRequestInfo): TJSONObject;
var
  S: string;
  LSS: TStringStream;
  LValue: TJSONValue;
begin
  if ARequest.PostStream = nil then Exit(TJSONObject.Create);
  LSS := TStringStream.Create('', TEncoding.UTF8);
  try
    ARequest.PostStream.Position := 0;
    LSS.CopyFrom(ARequest.PostStream);
    S := LSS.DataString;
  finally
    LSS.Free;
  end;
  if Trim(S) = '' then Exit(TJSONObject.Create);
  LValue := TJSONObject.ParseJSONValue(S);
  if LValue is TJSONObject then
    Result := TJSONObject(LValue)
  else
  begin
    LValue.Free;
    Result := TJSONObject.Create;
  end;
end;

class procedure TJSONHelper.SendJSON(AResponse: TIdHTTPResponseInfo;
  AObj: TJSONValue; ACode: Integer; AOwnsObj: Boolean);
begin
  AResponse.ResponseNo := ACode;
  AResponse.ContentType := 'application/json; charset=utf-8';
  AResponse.CharSet := 'utf-8';
  AResponse.ContentText := AObj.ToJSON;
  if AOwnsObj then AObj.Free;
end;

class procedure TJSONHelper.SendError(AResponse: TIdHTTPResponseInfo;
  ACode: Integer; const AMsg: string);
var
  LObj: TJSONObject;
begin
  LObj := TJSONObject.Create;
  LObj.AddPair('error', AMsg);
  SendJSON(AResponse, LObj, ACode);
end;

class procedure TJSONHelper.SendOK(AResponse: TIdHTTPResponseInfo;
  const AMessage: string);
var
  LObj: TJSONObject;
begin
  LObj := TJSONObject.Create;
  LObj.AddPair('message', AMessage);
  SendJSON(AResponse, LObj);
end;

end.