本文實例講述了php使用Header函數,PHP_AUTH_PW和PHP_AUTH_USER做用戶驗證的方法。分享給大家供大家參考，具體如下：
在php中，可以使用Header函數做一些有趣的事情，用戶驗證就是其中一個很有意思的功能。具體用法：
Header("WWW-Authenticate: Basic realm="USER LOGIN"");Header("HTTP/1.0 401 Unauthorized"); 在頁首設計這兩個Header函數，頁面在載入前會出現一個登錄框，要求輸入用戶名和密碼。習慣了在頁面登錄的我們，是否覺得這樣的登錄很原始，又很新奇呢？
為了獲取從這個對話框中傳來的用戶名和密碼，需要用到php提供的兩個特殊變量$PHP_AUTH_USER和$PHP_AUTH_PW，要這樣使用這兩個特殊變量好像需要在php.ini中設置相關的選項，不然就只能像下面這樣引用：
$_SERVER['PHP_AUTH_USER']$_SERVER['PHP_AUTH_PW']
獲取到用戶提交上來的用戶名和密碼之后，要怎樣處理邏輯就跟我們一般的程序處理沒有什么區別了。下面提供兩個例程供參考：
<?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);}?> 另外一個參考的例程：
<?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!';}?> 
