USER-LOGIN.PHP

Make PHP generated web content available only to your users! I derived this function from some PHP code that I used on the administrative portion of my database driven sites. userLogged() returns true if the cookies named UserName and PassWord exist in the MySQL database as a pair. If not, it displays the content of $LogInPage.

The main thought behind this was to display the same login for all my admin pages, without have to repeat the same HTML code. Another purpose for this code was to keep MySQL queries, and other back-end code from being executed without permission.

<?
function userLogged($LogInPage)
         {
         //Without this, PHP will create a local
         //variable called $HTTP_COOKIE_VARS.
         global $HTTP_COOKIE_VARS;

         $Entered_UserName = "";
         $Entered_PassWord = "";

         if(isset($HTTP_COOKIE_VARS["UserName"]) &&
            isset($HTTP_COOKIE_VARS["PassWord"]))
           {
           $Entered_UserName = $HTTP_COOKIE_VARS["UserName"];
           $Entered_PassWord = $HTTP_COOKIE_VARS["PassWord"];
           }

         $user_name_password = mysql_query("select id from users where " .
                                           "user_name = '" . $Entered_UserName . "' and " .
                                           "password = '" . md5($Entered_PassWord) . "'");

         $user_name_password = mysql_fetch_assoc($user_name_password);

         if($user_name_password === false)
           {
           //$LogInPage should be the name of an existing file
           //with alternative web content. If you don't wish to
           //provide such content, just pass the empty string.
           if($LogInPage != "") include($LogInPage);
           return(false);
           }
         else
           return(true);
         }
?>

<form name="login">
<table align="center" cellpadding="10" cellspacing="0" border="1">
<tr>
<td>User Name </td>
<td><input type="text" name="UserName" /></td>
</tr>

<tr>
<td>Password</td>
<td><input type="password" name="PassWord" /></td>
</tr>

<tr>
<td colspan="2" align="right">
<input type="button" value="log in"
       onclick="document.cookie = 'UserName=' + document.login.UserName.value;
                document.cookie = 'PassWord=' + document.login.PassWord.value;
                document.EmptyForm.submit();">
</td>
</tr>
</table>
</form>

<form name="EmptyForm" method="post">
</form>