php 进行 HTTP 认证

<?php
    if (!isset($_SERVER['PHP_AUTH_USER'])) {
        header('WWW-Authenticate: Basic realm="My Realm"');
        header('HTTP/1.0 401 Unauthorized');
        echo 'Text to send if user hits Cancel button';
        exit;
    } else {
        echo "<p>Hello {$_SERVER['PHP_AUTH_USER']}.</p>";
        echo "<p>You entered {$_SERVER['PHP_AUTH_PW']} as your password.</p>";
    }
?>

<?php
    $realm = 'Restricted area';
    //user => password
    $users = array('admin' => 'mypass', 'guest' => 'guest');
    if (empty($_SERVER['PHP_AUTH_DIGEST'])) {
        header('HTTP/1.1 401 Unauthorized');
        header('WWW-Authenticate: Digest realm="'.$realm.
            '" qop="auth" nonce="'.uniqid().'" opaque="'.md5($realm).'"');
        die('Text to send if user hits Cancel button');
    }
    // analyze the PHP_AUTH_DIGEST variable
    if (!($data = http_digest_parse($_SERVER['PHP_AUTH_DIGEST'])) ||
        !isset($users[$data['username']]))
        die('Wrong Credentials!');
    // generate the valid response
    $A1 = md5($data['username'] . ':' . $realm . ':' . $users[$data['username']]);
    $A2 = md5($_SERVER['REQUEST_METHOD'].':'.$data['uri']);
    $valid_response = md5($A1.':'.$data['nonce'].':'.$data['nc'].':'.$data['cnonce'].':'.$data['qop'].':'.$A2);
    if ($data['response'] != $valid_response)
        die('Wrong Credentials!');
    // ok, valid username & password
    echo 'Your are logged in as: ' . $data['username'];
    // function to parse the http auth header
    function http_digest_parse($txt)
    {
        // protect against missing data
        $needed_parts = array('nonce'=>1, 'nc'=>1, 'cnonce'=>1, 'qop'=>1, 'username'=>1, 'uri'=>1, 'response'=>1);
        $data = array();
        preg_match_all('@(\w+)=([\'"]?)([a-zA-Z0-9=./\_-]+)\2@', $txt, $matches, PREG_SET_ORDER);
        foreach ($matches as $m) {
             $data[$m[1]] = $m[3];
             unset($needed_parts[$m[1]]);
        }
        return $needed_parts ? false : $data;
    }
?>

<?php
    function authenticate() {
        header('WWW-Authenticate: Basic realm="Test Authentication System"');
        header('HTTP/1.0 401 Unauthorized');
        echo "You must enter a valid login ID and password to access this resource\n";
        exit;
    }
    if (!isset($_SERVER['PHP_AUTH_USER']) ||
        ($_POST['SeenBefore'] == 1 && $_POST['OldAuth'] == $_SERVER['PHP_AUTH_USER'])) {
        authenticate();
    } else {
        echo "<p>Welcome: {$_SERVER['PHP_AUTH_USER']}<br />";
        echo "Old: {$_REQUEST['OldAuth']}";
        echo "<form action='{$_SERVER['PHP_SELF']}' METHOD='post'>\n";
        echo "<input type='hidden' name='SeenBefore' value='1' />\n";
        echo "<input type='hidden' name='OldAuth' value='{$_SERVER['PHP_AUTH_USER']}' />\n";
        echo "<input type='submit' value='Re Authenticate' />\n";
        echo "</form></p>\n";
    }