duanhe6464 2013-10-16 18:43
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PHP mysql以前声明的函数问题

I'll make this as short and sweet as possible.

I have this script called usernameget.php which echos the currently logged in username:

<?php 
include 'functions.php';
include 'db_connect.php';
sec_session_start();

$userId = $_SESSION['user_id'];

if(login_check($mysqli) == true) {

$con=mysqli_connect("localhost","myusername","mypass","mysqldb");
// Check connection
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }


$result = mysqli_query($con,"SELECT members.username FROM members WHERE id= $userId");

while ($row = mysqli_fetch_assoc($result)) 
{
   echo $row['username'];
}

/* free result set */
mysqli_free_result($result);

mysqli_close($con);

} else {
   echo 'Null User <br/>';
}

?>

This script uses functions.php (part of a secure login script located here: http://www.wikihow.com/Create-a-Secure-Login-Script-in-PHP-and-MySQL#Create_PHP_Functions ) in order to function. sec_session_start(); is just a custom session_start, but functions.php also makes it possible to get the username via $user_id.

The problem is, when I include usernameget.php in the main page (which also uses functions.php to secure,) it throws errors because it's trying to redeclare sec_session_start();

I can strip usernameget.php of this security but obviously since it banks on functions.php / sec_session_start(); it doesn't work afterwards. I've tried to write a specific USERNAMEGETfunctions.php without the session stuff for usernameget.php to use but I'm not adept enough to get it working, and it feels like an inelegant solution.

So as I understand it: functions.php and sec_session_start(); are used to secure the main page so the includes on the main page can't use functions.php or it will conflict. Would anyone be able to show me how to get this script going without redeclaring/conflicting?

Included below is the entire functions.php

<?php
function sec_session_start() {
        $session_name = 'sec_session_id'; // Set a custom session name
        $secure = false; // Set to true if using https.
        $httponly = true; // This stops javascript being able to access the session id. 

        ini_set('session.use_only_cookies', 1); // Forces sessions to only use cookies. 
        $cookieParams = session_get_cookie_params(); // Gets current cookies params.
        session_set_cookie_params($cookieParams["lifetime"], $cookieParams["path"], $cookieParams["domain"], $secure, $httponly); 
        session_name($session_name); // Sets the session name to the one set above.
        session_start(); // Start the php session
        session_regenerate_id(); // regenerated the session, delete the old one.  
}




function login($email, $password, $mysqli) {
   // Using prepared Statements means that SQL injection is not possible. 
   if ($stmt = $mysqli->prepare("SELECT id, username, password, salt FROM members WHERE email = ? LIMIT 1")) { 
      $stmt->bind_param('s', $email); // Bind "$email" to parameter.
      $stmt->execute(); // Execute the prepared query.
      $stmt->store_result();
      $stmt->bind_result($user_id, $username, $db_password, $salt); // get variables from result.
      $stmt->fetch();
      $password = hash('sha512', $password.$salt); // hash the password with the unique salt.

      if($stmt->num_rows == 1) { // If the user exists
         // We check if the account is locked from too many login attempts
         if(checkbrute($user_id, $mysqli) == true) { 
            // Account is locked
            // Send an email to user saying their account is locked
            return false;
         } else {
         if($db_password == $password) { // Check if the password in the database matches the password the user submitted. 
            // Password is correct!


               $user_browser = $_SERVER['HTTP_USER_AGENT']; // Get the user-agent string of the user.

               $user_id = preg_replace("/[^0-9]+/", "", $user_id); // XSS protection as we might print this value
               $_SESSION['user_id'] = $user_id; 
               $username = preg_replace("/[^a-zA-Z0-9_\-]+/", "", $username); // XSS protection as we might print this value
               $_SESSION['username'] = $username;
               $_SESSION['login_string'] = hash('sha512', $password.$user_browser);
               // Login successful.
               return true;    
         } else {
            // Password is not correct
            // We record this attempt in the database
            $now = time();
            $mysqli->query("INSERT INTO login_attempts (user_id, time) VALUES ('$user_id', '$now')");
            return false;
         }
      }
      } else {
         // No user exists. 
         return false;
      }
   }
}




function checkbrute($user_id, $mysqli) {
   // Get timestamp of current time
   $now = time();
   // All login attempts are counted from the past 2 hours. 
   $valid_attempts = $now - (2 * 60 * 60); 

   if ($stmt = $mysqli->prepare("SELECT time FROM login_attempts WHERE user_id = ? AND time > '$valid_attempts'")) { 
      $stmt->bind_param('i', $user_id); 
      // Execute the prepared query.
      $stmt->execute();
      $stmt->store_result();
      // If there has been more than 5 failed logins
      if($stmt->num_rows > 5) {
         return true;
      } else {
         return false;
      }
   }
}




function login_check($mysqli) {
   // Check if all session variables are set
   if(isset($_SESSION['user_id'], $_SESSION['username'], $_SESSION['login_string'])) {
     $user_id = $_SESSION['user_id'];
     $login_string = $_SESSION['login_string'];
     $username = $_SESSION['username'];

     $user_browser = $_SERVER['HTTP_USER_AGENT']; // Get the user-agent string of the user.

     if ($stmt = $mysqli->prepare("SELECT password FROM members WHERE id = ? LIMIT 1")) { 
        $stmt->bind_param('i', $user_id); // Bind "$user_id" to parameter.
        $stmt->execute(); // Execute the prepared query.
        $stmt->store_result();

        if($stmt->num_rows == 1) { // If the user exists
           $stmt->bind_result($password); // get variables from result.
           $stmt->fetch();
           $login_check = hash('sha512', $password.$user_browser);
           if($login_check == $login_string) {
              // Logged In!!!!
              return true;
           } else {
              // Not logged in
              return false;
           }
        } else {
            // Not logged in
            return false;
        }
     } else {
        // Not logged in
        return false;
     }
   } else {
     // Not logged in
     return false;
   }
}

?>
  • 写回答

2条回答 默认 最新

  • doutu3352 2013-10-16 18:47
    关注

    Don't use plain include for core function libraries, the kind which tend to get included in ALL your scripts. Use include_once instead, so that PHP will only ever include the file once, and then ignore any further include attempts. This will prevent your function redeclaration errors.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论
  • dongyikong6207 2013-10-16 19:14
    关注

    You must use require_once instead include_once because your program not will run without that files...

    include_once produce warning when try to include the file and it fails. require_once produce fatal error when try to include the and it fails.

    For core libs, you should use require_once. (http://www.php.net/manual/pt_BR/function.require.php)

    require is identical to include except upon failure it will also produce a fatal E_COMPILE_ERROR level error. In other words, it will halt the script whereas include only emits a warning (E_WARNING) which allows the script to continue.
    
    评论
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