【CodeIgniter】Digest（ダイジェスト）認証ライブラリ

Digest_auth.php

<?php
if (!defined('BASEPATH'))
	exit('No direct script access allowed');
	
class Digest_auth
{
	private $realm         = "Restricted Area";
	
	private $username      = "username";
	
	private $password      = "password";
	
	private $logged_in_key = 'logged_in';
	
	public function __construct(array $config = array())
	{
		$this->CI = & get_instance();
		$this->CI->load->library('session');
		
		if(count($config))
		{
			$this->initialize($config);
		}
	}
	
	public function initialize($config = array())
	{
		foreach ($config as $key => $val)
		{
			if (isset($this->$key))
			{
				$method = 'set_'.$key;
				if (method_exists($this, $method))
				{
					$this->$method($val);
				}
				else
				{
					$this->$key = $val;
				}
			}
		}
		return $this;
	}
	
	private function set_username($username)
	{
		$this->username = $username;
	}
	
	private function set_password($password)
	{
		$this->password = $password;		
	}
	
	public function get_username()
	{
		return $this->username;
	}
	
	private function get_password()
	{
		return $this->password;
	}
	
	public function login()
	{
		$logged_in = $this->CI->session->userdata($this->logged_in_key);
		
		if ($logged_in !== true)
		{
			if ($this->auth())
			{
				$this->CI->session->set_userdata($this->logged_in_key, true);
			} else
			{
				header('HTTP/1.1 401 Authorization Required');
				header('WWW-Authenticate: Digest realm="' . $this->realm . '", qop="auth", nonce="' . uniqid() . '", opaque="' . md5($this->realm) . '"');
				header('Content-type: text/html; charset='.mb_internal_encoding());
				die("Please enter a valid username and password");
			}
		}
	}
	
	private function auth()
	{
		if (!$this->CI->input->server('PHP_AUTH_DIGEST'))
		{
			return false;
		} else
		{
			// PHP_AUTH_DIGEST 変数を精査する
			$data = $this->http_digest_parse($this->CI->input->server('PHP_AUTH_DIGEST'));
			if (!$data || $data['username'] != $this->get_username())
				return false;
			
			// 有効なレスポンスを生成する
			$hash_1 = md5(sprintf("%s:%s:%s", $data['username'], $this->realm, $this->get_password()));
			$hash_2 = md5(sprintf("%s:%s", $this->CI->input->server('REQUEST_METHOD'), $data['uri']));
			$valid_response = md5(sprintf("%s:%s:%s:%s:%s:%s", $hash_1, $data['nonce'], $data['nc'], $data['cnonce'], $data['qop'], $hash_2));
			
			if ($data['response'] != $valid_response)
				return false;
				
			return true;
		}
	}
	
	// http auth ヘッダをパースする関数
	private function http_digest_parse($txt)
	{
		// データが失われている場合への対応
		$needed_parts = array(
			'nonce'    => true,
			'nc'       => true,
			'cnonce'   => true,
			'qop'      => true,
			'username' => true,
			'uri'      => true,
			'response' => true
		);
		
		$data = array();
		
		$keys = implode('|', array_keys($needed_parts));
		preg_match_all('@(' . $keys . ')=(?:([\'"])([^\2]+?)\2|([^\s,]+))@', $txt, $matches, PREG_SET_ORDER);
	
		foreach ($matches as $m) {
			$data[$m[1]] = $m[3] ? $m[3] : $m[4];
			unset($needed_parts[$m[1]]);
		}
		
		return $needed_parts ? false : $data;
	}
}

Welcome.php

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

class Welcome extends CI_Controller {


	public function index()
	{
		$this->load->view('welcome_message');
	}
	
	public function digest_auth()
	{
		$this->load->library('Digest_auth', array(
			'username' => 'username',
			'password' => 'password'
		));
		
		$this->digest_auth->login();
		
	}
}