Simplifying a rest php api

api.php

<?php

class Api 
{
    public static function is_password($password, $confirm) 
    {
        $v = Validator::make(array(
            'password' => $password,
            'password_confirmation' => $confirm
        ), array(
            'password' => 'required|confirmed'
        ));
        
        if ($v->fails()) {
            $message = current($v->errors->messages);
            return $message[0];
        }   
        
        return true;
    }
    
    public static function is_email($email, $unique = true)
    {
        $v = Validator::make(array(
            'email' => $email
        ), array(
            'email' => 'required|email' . ($unique ? '|unique:users' : ''),
        ));
    
        if ($v->fails()) {
            return $v->errors;
        }
    
        return true;
    }
    
    public static function clean($html)
    {
        if (is_array($html)) {
            foreach ($html as $key => $value)
                $html[$key] = s($value);
    
            return $html;
        }
    
        return Sanitize::purify($html);
    }

    public static function get_inputs()
    {
        if ($_SERVER['REQUEST_METHOD'] == 'PUT') {            
            $request_string = file_get_contents('php://input');
            $inputs = json_decode($request_string, 1);
        } else {
            $inputs = Input::all();
        }
        
        return static::clean($inputs);
    }

    public static function update(&$model, $ignore = array())
    {
        $inputs = self::get_inputs();
        
        foreach ($inputs as $key => $value) {
            if (is_array($ignore)) {
                if (in_array($key, $ignore)) {
                    continue;
                }
            }
            
            $model->$key = $s[$key];   
        }
        
        return $inputs;
    }
    
    public static function json($data) 
    {
        return json($data);   
    }
    
    public static function success($message = true)
    {
        return Response::json(array(
            'success' => $message 
        ));
    }
    
    public static function error($message)
    {
        return Response::json(array(
            'error' => $message
        ), 404);
    }
}

controller.php

<?php
class Api_V1_User_Controller extends Base_Controller
{
    public function post_index()
    {
        $user = new User;
        $s = Api::update($user, array('password', 'password_confirmation'));
        
        $pass_check = Api::is_password($s['password'], $s['password_confirmation']);
        if ($pass_check !== true) {
            return Api::error($pass_check);
        }
        
        if (! Api::is_email($user->email)) {
            return Api::error("Either email was invalid or is already registered.");
        }
    
        $user->account_user_id = Auth::user()->account_user_id;
        $user->password = Hash::make($s['password']);
        $user->permissions = Auth::user()->permissions;
        $user->save();
    
        Api::success(array(
            'user' => to_json($user),
        ));
    }
}