CodeIgniter JSON Response Controller - Converts data into JSON format and sends it back.

RESPONSE_Controller.php

<?php
defined( 'BASEPATH' ) OR exit( 'No direct script access allowed' );

/**
 * CodeIgniter JSON Response Controller
 * Converts data into JSON format and sends it back.
 *
 * @package         CodeIgniter
 * @author          Troyan Victor, WebDesignSun Team
 * @license         MIT
 * @version         1.0.0
 */

abstract class RESPONSE_Controller extends CI_Controller {
    /**
     * Set HTTP Status.
     *
     * @param int
     */
    protected function set_HTTP_status( $code = 200 )
    {
        if ( function_exists( 'http_response_code' ) ) {
            http_response_code( $code );
        } else {
            switch ( $code ) {
                case 100:
                    $status = 'Continue';
                    break;
                case 101:
                    $status = 'Switching Protocols';
                    break;
                case 200:
                    $status = 'OK';
                    break;
                case 201:
                    $status = 'Created';
                    break;
                case 202:
                    $status = 'Accepted';
                    break;
                case 203:
                    $status = 'Non-Authoritative Information';
                    break;
                case 204:
                    $status = 'No Content';
                    break;
                case 205:
                    $status = 'Reset Content';
                    break;
                case 206:
                    $status = 'Partial Content';
                    break;
                case 300:
                    $status = 'Multiple Choices';
                    break;
                case 301:
                    $status = 'Moved Permanently';
                    break;
                case 302:
                    $status = 'Moved Temporarily';
                    break;
                case 303:
                    $status = 'See Other';
                    break;
                case 304:
                    $status = 'Not Modified';
                    break;
                case 305:
                    $status = 'Use Proxy';
                    break;
                case 400:
                    $status = 'Bad Request';
                    break;
                case 401:
                    $status = 'Unauthorized';
                    break;
                case 402:
                    $status = 'Payment Required';
                    break;
                case 403:
                    $status = 'Forbidden';
                    break;
                case 404:
                    $status = 'Not Found';
                    break;
                case 405:
                    $status = 'Method Not Allowed';
                    break;
                case 406:
                    $status = 'Not Acceptable';
                    break;
                case 407:
                    $status = 'Proxy Authentication Required';
                    break;
                case 408:
                    $status = 'Request Time-out';
                    break;
                case 409:
                    $status = 'Conflict';
                    break;
                case 410:
                    $status = 'Gone';
                    break;
                case 411:
                    $status = 'Length Required';
                    break;
                case 412:
                    $status = 'Precondition Failed';
                    break;
                case 413:
                    $status = 'Request Entity Too Large';
                    break;
                case 414:
                    $status = 'Request-URI Too Large';
                    break;
                case 415:
                    $status = 'Unsupported Media Type';
                    break;
                case 500:
                    $status = 'Internal Server Error';
                    break;
                case 501:
                    $status = 'Not Implemented';
                    break;
                case 502:
                    $status = 'Bad Gateway';
                    break;
                case 503:
                    $status = 'Service Unavailable';
                    break;
                case 504:
                    $status = 'Gateway Time-out';
                    break;
                case 505:
                    $status = 'HTTP Version not supported';
                    break;
                default:
                    exit( 'Unknown http status code "' . htmlentities( $code ) . '"' );
                    break;
            }

            $protocol = isset( $_SERVER['SERVER_PROTOCOL'] ) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.0';

            header( $protocol . ' ' . $code . ' ' . $status );
        }
    }

    /**
     * Generate response.
     *
     * @param array
     * @param NULL
     */
    protected function send_JSON_response( $data, $code = NULL )
    {
        $this->send_response( NULL === $data ? NULL : json_encode( $data ), $code, array( 'Content-Type' => 'application/json' ) );
    }

    /**
     * Send Data in response.
     *
     * @param array
     * @param NULL
     * @param array
     */
    protected function send_response( $data, $code = NULL, $headers = array() )
    {
        if ( NULL === $data && NULL === $code ) {
            $code = 404;
        } else if ( NULL === $code ) {
            $code = 200;
        }

        $this->set_HTTP_status( $code );

        foreach ( $headers as $key => $value ) header( $key . ': ' . $value );

        echo $data;

        // exit
        $this->terminate( 0 );
    }

    /**
     * Complete the query.
     *
     * @param int
     */
    protected function terminate( $code = 0 )
    {
        exit( $code );
    }
}