設定路由 application/config/routes.php

$route['api/v1/url/(:any)']['DELETE'] = 'api/v1/url/delete/$1';

寫Controller application/controllers/api/v1/url.php

public function delete($url_shorten) {
    $database = $this->load->database('default',true); //設定database連線
    $query = $database //檢查紀錄是否存在
        ->from('urls')
        ->where('url_shorten',$url_shorten)
        ->get();
    if (!$query -> num_rows() > 0) { //不大於零: 不存在 
        http_response_code(404); //回應HTTP 404 Not Found
        print_r(
            json_encode(
                array(
                    'status' => 'error',
                    'code' => 404,
                    'message' => 'not-found'
                )
            )
        );
        die();
    }
    $database //執行刪除
        ->where('url_shorten',$url_shorten)
        ->delete('urls');
    $dberror = $database->error(); //try catch DB錯誤
    if ($dberror['code'] != 00000) {
        print_r(
            json_encode(
                array(
                    'status' => 'error',
                    'message' => 'an database error occurred',
                    'code' => $dberror['code'],
                )
            )
        );
        set_status_header(500,'Internal Server Error - An database error occurred'); //如果錯誤，回復http 500
    } else {
        print_r(
            json_encode(
                array(
                    'status' => 'success',
                )
            )
        );   
    }
}