環境資訊：
- Ubuntu 14.04 64 Bit (lsb_release -a)
- PHP 5.5.9 (php -v)
- CodeIgniter 2.2.0 (echo CI_VERSION)
接著，透過
github.com/chriskacerguis/codeigniter-restserver 擴充 CodeIgniter：
$ wget https://raw.githubusercontent.com/chriskacerguis/codeigniter-restserver/master/application/config/rest.php -O /path/ci_proj/application/config/rest.php
$ wget https://raw.githubusercontent.com/chriskacerguis/codeigniter-restserver/master/application/libraries/Format.php -O /path/ci_proj/application/libraries/Format.php
$ wget https://raw.githubusercontent.com/chriskacerguis/codeigniter-restserver/master/application/libraries/REST_Controller.php -O /path/ci_proj/application/libraries/REST_Controller.php
接著，請確認 application/config/rest.php 設定：
$config[rest_default_format] = 'json'; // 預設為 xml
之後，就可以撰寫簡單的 RESTful API 啦：
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
require(APPPATH.'/libraries/REST_Controller.php');
class Item extends REST_Controller {
public function index_get() {
$this->list_get();
}
public function index_post() {
$this->add_post();
}
public function index_put() {
$this->update_put();
}
public function index_delete() {
$this->delete_delte();
}
public function list_get() {
echo "list";
}
public function add_post() {
echo "create";
}
public function update_put() {
echo "put";
}
public function remove_delete() {
echo "remove";
}
}
測試方式：
取得清單(GET)
$ curl -X GET http://localhost/ci_proj/item/list
$ curl -X GET http://localhost/ci_proj/item/
新增資料(POST)
$ curl -X POST http://localhost/ci_proj/item/add
$ curl -X POST http://localhost/ci_proj/item/
更新資料(PUT)
$ curl -X PUT http://localhost/ci_proj/item/update
$ curl -X PUT http://localhost/ci_proj/item/
刪除資料(DELETE)
$ curl -X DELETE http://localhost/ci_proj/item/delete
$ curl -X DELETE http://localhost/ci_proj/item/
也可以用 wget --method GET/POST/PUT/DELETE 等進行測試。
至於 RESTful 常見的 HTTP STATUS CODE，可以參考
Using HTTP Methods for RESTful Services
例如:
取得清單成功回應 200 OK，失敗則為 404 NOT FOUND；新增資料成功 200 OK 或是 201 LOCATION 到新增項目的 URI，失敗為 404 NOT FOUND；更新資料成功為 200 OK，失敗為 404 NOT FOUND；刪除資料成功為 200 OK，失敗為 404 NOT FOUND。
接著，是設計每個 GET, POST, PUT, DELETE API 細節，可以分別使用 $this->get('param')、$this->post('param')、$this->put('param') 和 $this->delete('param') 取得對應資料，而回應時，需要的 HTTP Status Code 可以使用：
$this->response( array('status' => true), 200);
$this->response( array('status' => false, 'error' => 'error message'), 400);
$this->response( array('status' => false, 'error' => 'error message'), 404);
若要 debug 的話，大概可以用：
$this->response( array('status' => true, 'get' => $this->get(), 'post' => $this->post(), 'put' => $this->put(), 'delete' => $this->delete() ), 200);
搭配 curl -i -X GET|POST|PUT|DELETE -d 'key=value' 方式進行，除了可以看到 HTTP Response code 外，也能看到 get, post, put, delete 各種參數資訊：
$ curl -i -X DELETE -d "haha=hehe" CGI
HTTP/1.1 200 OK
Server: Apache/2.4.7 (Ubuntu)
X-Powered-By: PHP/5.5.9-1ubuntu4.5
Content-Length: 68
Content-Type: application/json; charset=utf-8
{"status":true,"get":[],"post":[],"put":[],"delete":{"haha":"hehe"}}
