header() function in php : No any redirection!_问答_开发者

I have written a very very very simple!! script in php. header redirection not working. 1- encoding : UTF-8 without BOM 2- with adding ob_start() the problem is countiueing. What is wrong in my code;

<?php  session_start();
   require_once("funcs.php"); 
   db_connection();
   $username = $_POST['username'];
   $password = $_POST['pwd'];
   $submit = $_POST['login'];
   if($submit){
    if (!filled_out($_POST)) {
                echo "please fill all fields";
            }
     else{
        $query = "SELECT * FROM *** WHERE username ='{$username}' AND password ='{$password}'";
        $result = mysql_query($query);
            if(mysql_num_rows($result) == 1){
              开发者_运维知识库   $found_user = mysql_fetch_array($result);
                 $_SESSION['id']  = $found_user['id'];
                 $_SESSION['username'] = $found_user['username'];
                 $_SESSION['password'] = $found_user['password'];
                 setcookie(session_name(), '', time()+86400, '/');
                 header("Location: tst.php");
                 }
                 else{
                    echo "incorrect username or password";
                 }

           }
      }     


?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>
<body>
<form id="form1" name="form1" method="post" action="">
  <p>
    <label for="username">
      Username:
    </label>
    <input type="text" name="username" id="username" />
  </p>
  <p>
    <label for="textfield">
      Password
    </label>
    <input type="password" name="pwd" id="pwd" />
  </p>
  <p>
    <input name="login" type="submit" id="login" value="Log in" />
  </p>
</form>
</body>
</html>
<?php 

 db_disconnect();

?>

and tst.php:

<?php session_start();  
  require_once("funcs.php");    
  if (!isset($_SESSION['id'])){
           header("Location : login.php");
         }
 ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
</head>
<body>
<table id="structure">
  <tr>
    <td id="navigation">&nbsp;</td>
    <td id="page"><?php echo "welcome"."". $_SESSION['username']; ?></td>
  </tr>
</table>
</body>
</html>

wthit oppening tst.php directly, header() doesnot redirect to login.php

Try adding die():

  header("Location: tst.php");
  die();

You should always add a die() because a location header is just a request to the browser to change the page. If you don't die(), the rest of the page will still reach the browser, including possibly sensitive data the user is not meant to see.

Try removing the space after "Location":

header("Location: login.php");

Please heed my comment about formatting your code correctly as it's extremely difficult to spot anything else that may be amiss.

Check for white space before your opening <?php tags. It's hard to tell from your formatting here whether there is any, but the whitespace will be sent before your code executes, preventing headers. Also check for white space after any closing tags in included files. (better practice is to omit closing tags altogether)

old answer

You're using setcookie() which will send headers, then trying to redirect. You cannot redirect once headers have been sent. (sorry, this was incorrect)

I guess the redirect works, but you overwrite the Session-Cookie with an empty value. So the tst.php creates a new empty Session and redirects back to login.php.

Try:

// DELETE this line: setcookie(session_name(), '', time()+86400, '/');
header("Location: tst.php?".SID);

Importent: header+session always need SID for not loosing the session!

Corrected: Thanks to @Pekka.

header is not just a php function. It really modifies a part of http header, so it is impossible to have a part of header, then html data, then another header. To make it work, you should put your header at the beginning of the file, before any html output is done.

The redirection can take a relative or absolute URL. The problem is with the space BEFORE the colon. Try it like this: