本文实例讲述了php使用Header函数,PHP_AUTH_PW和PHP_AUTH_USER做用户验证的方法。分享给大家供大家参考，具体如下：
在php中，可以使用Header函数做一些有趣的事情，用户验证就是其中一个很有意思的功能。具体用法：
Header("WWW-Authenticate: Basic realm="USER LOGIN"");Header("HTTP/1.0 401 Unauthorized"); 在页首设计这两个Header函数，页面在载入前会出现一个登录框，要求输入用户名和密码。习惯了在页面登录的我们，是否觉得这样的登录很原始，又很新奇呢？
为了获取从这个对话框中传来的用户名和密码，需要用到php提供的两个特殊变量$PHP_AUTH_USER和$PHP_AUTH_PW，要这样使用这两个特殊变量好像需要在php.ini中设置相关的选项，不然就只能像下面这样引用：
$_SERVER['PHP_AUTH_USER']$_SERVER['PHP_AUTH_PW']
获取到用户提交上来的用户名和密码之后，要怎样处理逻辑就跟我们一般的程序处理没有什么区别了。下面提供两个例程供参考：
<?phpif(!isset($PHP_AUTH_USER)) {Header("WWW-authenticate: basic realm="XXX"");Header("HTTP/1.0 401 Unauthorized");$title="Login Instructions";?><blockquote>In order to enter this section of the web site, you must be an XXXsubscriber. If you are a subscriber and you are having trouble loggingin,please contact <a href="mailto:support@xxx.com">support@xxx.com</a>.</blockquote><?phpexit;} else {mysql_pconnect("localhost","nobody","") or die("Unable to connect to SQL server");mysql_select_db("xxx") or die("Unable to select database");$user_id=strtolower($PHP_AUTH_USER);$password=$PHP_AUTH_PW;$query = mysql_query("select * from users where user_id='$user_id' and password='$password'");if(!mysql_num_rows($query)) {Header("WWW-authenticate: basic realm="XXX"");Header("HTTP/1.0 401 Unauthorized");$title="Login Instructions";?><blockquote>In order to enter this section of the web site, you must be an XXXsubscriber. If you are a subscriber and you are having troublelogging in,please contact <a href="mailto:support@xxx.com">support@xxx.com</a>.</blockquote><?phpexit;}$name=mysql_result($query,0,"name");$email=mysql_result($query,0,"email");mysql_free_result($query);}?> 另外一个参考的例程：
<?php//assume user is not authenticated$auth = false;$user = $_SERVER['PHP_AUTH_USER'];$pass = $_SERVER['PHP_AUTH_PW'];if ( isset($user) && isset($pass) ){//connect to dbinclude 'db_connect.php';//SQL query to find if this entered username/password is in the db$sql = "SELECT * FROM healthed_workshop_admin WHEREuser = '$PHP_AUTH_USER' ANDpass = '$PHP_AUTH_PW'";//put the SQL command and SQL instructions into variable$result = mysql_query($sql) or die('Unable to connect.');//get number or rows in command; if more than 0, row is found$num_matches = mysql_num_rows($result);if ($num_matches !=0){//matching row found authenticates user$auth = true;}}if (!$auth){header('WWW-Authenticate: Basic realm="Health Ed Presentation Admin"');header('HTTP/1.0 401 Unauthorized');echo 'You must enter a valid username & password.';exit;}else{echo 'Success!';}?>
