public class SharinPixActionDemoCtrl {
    public String parameters {get; set;}
    
    public SharinPixActionDemoCtrl(ApexPages.StandardController controller) {
        Id accId = controller.getId();
        
        Map<String, Object> params = new Map<String, Object> {
            'exp' => 1528281766,
            'abilities' => new Map<String, Object> {
                accId => new Map<String, Object> {
                    'Access' => new Map<String, Object> {
                        'see' => true,
                        'image_list' => true,
                        'image_upload' => true,
                        'image_tag' => true,
                        'image_delete' => true
                    },
                    'Tags' => new Map<String, Object> {
                        'car' => new Map<String, String> {
                            'en' => 'car',
                            'fr' => 'voiture'
                        }        
                    },
                    'Action' => new List<String> {
                        'Add to description'        
                    }
                }
            } 
        };
        parameters = JSON.serialize(params);
    }
}