Using TJSONIniFile topic

Declaration

Using TJSONIniFile

Description

TJSONIniFile provides a JSON-based alternative to traditional ini files while maintaining the familiar TCustomIniFile interface. Configuration data is stored as JSON objects where sections become JSON objects and keys within sections become properties of those objects.

The following example demonstrates basic reading and writing operations:

program JsonIniExample;

uses
  JsonIni, SysUtils;

var
  IniFile: TJSONIniFile;
begin
  // Create or open a JSON ini file
  IniFile := TJSONIniFile.Create('config.json');
  try
    // Write configuration values
    IniFile.WriteString('Database', 'Host', 'localhost');
    IniFile.WriteInteger('Database', 'Port', 5432);
    IniFile.WriteBool('Database', 'UseSSL', True);

    IniFile.WriteString('UI', 'Theme', 'Dark');
    IniFile.WriteInteger('UI', 'Width', 1024);
    IniFile.WriteInteger('UI', 'Height', 768);
    
    IniFile.UpdateFile;

    // Read configuration values with defaults
    WriteLn('Database Host: ', IniFile.ReadString('Database', 'Host', 'unknown'));
    WriteLn('Database Port: ', IniFile.ReadInteger('Database', 'Port', 0));
    WriteLn('Use SSL: ', IniFile.ReadBool('Database', 'UseSSL', False));

    WriteLn('UI Theme: ', IniFile.ReadString('UI', 'Theme', 'Light'));
    WriteLn('Window Size: ', IniFile.ReadInteger('UI', 'Width', 800), 'x',
            IniFile.ReadInteger('UI', 'Height', 600));

  finally
    IniFile.Free;
  end;
end.

The resulting JSON file structure looks like this:

{
  "Database": {
    "Host": "localhost",
    "Port": 5432,
    "UseSSL": true
  },
  "UI": {
    "Theme": "Dark",
    "Width": 1024,
    "Height": 768
  }
}

For applications that need to control when changes are written to disk, use the CacheUpdates property:

var
  IniFile: TJSONIniFile;
begin
  IniFile := TJSONIniFile.Create('config.json');
  try
    // Cache changes in memory
    IniFile.CacheUpdates := True;

    // Make multiple changes
    IniFile.WriteString('Section1', 'Key1', 'Value1');
    IniFile.WriteInteger('Section1', 'Key2', 42);
    IniFile.WriteString('Section2', 'Key1', 'Value2');

    // Write all changes to file at once
    IniFile.UpdateFile;

  finally
    IniFile.Free;
  end;
end.

To convert existing traditional ini files to JSON format, use the ConvertIni class method:

// Convert with type detection
TJSONIniFile.ConvertIni('old.ini', 'new.json', False);

// Convert keeping everything as strings
TJSONIniFile.ConvertIni('old.ini', 'new.json', True);

See also

• TCustomIniFile
• TMemIniFile
• TJSONIniFile