PHP Header Already Sent Error

Question

I am having trouble with my code.It is supposed to redirect to a page if the login is okay.I am getting a successfully login but I am getting a error with the header forward.Here is the line which the problem is occurring:

header("Location: members.php");

Here is the error message: Warning: Cannot modify header information - headers already sent

Here is my full code for the page if it helps:

<?php 
    // Connects to your Database 
    include("dbconnect.php");
    mysql_select_db("maxgee_close2");
    //Checks if there is a login cookie

    if(isset($_COOKIE['ID_my_site']))
     //if there is, it logs you in and directes you to the members page
    { 
        $username = $_COOKIE['ID_my_site']; 
        $password = $_COOKIE['Key_my_site'];
        $check = mysql_query("SELECT * FROM users WHERE username = '$username'")or die(mysql_error());
        while($info = mysql_fetch_array( $check )) 
        {
            if ($pass != $info['password'])
            {
            }
            else
            {
                header("Location: members.php");
            }
        }
    }
    //if the login form is submitted 
    if (isset($_POST['submit'])) { // if form has been submitted
     // makes sure they filled it in
        if(!$_POST['username'] | !$_POST['password']) {
            die('You did not fill in a required field.');
        }
        // checks it against the database

        if (!get_magic_quotes_gpc()) {
            $_POST['email'] = addslashes($_POST['email']);
        }
        $check = mysql_query("SELECT * FROM users WHERE username = '".$_POST['username']."'")or die(mysql_error());

        //Gives error if user dosen't exist
        $check2 = mysql_num_rows($check);
        if ($check2 == 0) {
            die('That user does not exist in our database. <a href=add.php>Click Here to Register</a>');
        }
        while($info = mysql_fetch_array( $check ))  
        {
            $_POST['password'] = stripslashes($_POST['password']);

            $info['password'] = stripslashes($info['password']);

            $_POST['password'] = md5($_POST['password']);

            //gives error if the password is wrong

            if ($_POST['password'] != $info['password']) {
                die('Incorrect password, please try again.');
            }
            else 
            { 
                // if login is ok then we add a cookie 
                $_POST['username'] = stripslashes($_POST['username']); 
                $hour = time() + 3600; 

              //then redirect them to the members area and the line with the error
              header("Location: members.php");
            }
        } 
      }
      else
      { 
        // if they are not logged in
         ?>
         <form action="<?php echo $_SERVER['PHP_SELF']?>" method="post">
         <h1>Login</h1>
         Username:
        <input type="text" name="username" maxlength="40"> 
        Password:
        <input type="password" name="password" maxlength="50"> 
        <input type="submit" name="submit" value="Login">
        </form> 
    <?php 
     } 
     include("topsite.php");
    ?>

No problem you should accept one of the answers that helped you, and welcome to stack overflow! — StackOverflowed, Oct 22 '12 at 05:20
I will....I Still have the restriction where I have to wait 15 minutes and then I will! @StackOverflowed — maxgee, Oct 22 '12 at 05:21
You have some SQL injection vulnerabilities as well - setting the `$_COOKIE['ID_my_site']` value to `'; DROP TABLE users; SELECT '` for example. — doublesharp, Oct 22 '12 at 05:24

score 1 · Answer 1 · answered Oct 22 '12 at 05:11

1

There is a space at the starting of your code..

<?php

Try after removing that.

For more info look at this.

answered Oct 22 '12 at 05:11

Ashwini Agarwal

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Thank you!My bad stupid mistake! – maxgee Oct 22 '12 at 05:18
Can you check the code and see if there is a problem with adding the cookie because I am having trouble with the members page finding the cookie? – maxgee Oct 22 '12 at 05:20

score 1 · Answer 2 · answered Oct 22 '12 at 05:12

1

You probably have a space before your <?php tag. It looks like it's there in your example.

answered Oct 22 '12 at 05:12

doublesharp

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Thank you!My bad stupid mistake! – maxgee Oct 22 '12 at 05:17

score 1 · Answer 3 · answered Oct 22 '12 at 05:12

1

There's a space before php tag. Any space outside of your PHP tags will be considered whitespace for output.

answered Oct 22 '12 at 05:12

StackOverflowed

5,854
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Thank you!My bad stupid mistake! – maxgee Oct 22 '12 at 05:18

score 1 · Accepted Answer · answered Oct 22 '12 at 05:19

1

You have written

$password = $_COOKIE['Key_my_site'];

But you are comparing $pass with $info['password'] and it should be

    if ($password != $info['password']){

    } else {

        header("Location: members.php");
    }

You can modify your query in a better way by writing

$check = mysql_query("SELECT * FROM users WHERE username = '$username' AND password = '$password'")or die(mysql_error());

if(mysql_num_rows($check) == 0) header("Location: members.php");

answered Oct 22 '12 at 05:19

Abhishek Saha

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1
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How does that solve the original issue? – John Dvorak Oct 22 '12 at 05:21
if $pass is not define, it will throw error which acts as an output and that is triggering the header error. Basically it prints before the header. – Abhishek Saha Oct 22 '12 at 05:23
@JanDvorak I asked for him to look for a different problem...he is just helping me out! – maxgee Oct 22 '12 at 05:24
`display errors` should always be disabled on production. Good point anyways. – John Dvorak Oct 22 '12 at 05:26
Worth noting that the mysql php extension is deprecated and that the code contains sql injection vulnerabilities. – doublesharp Oct 22 '12 at 05:31
@doublesharp, I dont disagree. But he has asked for how to rectify the error and not good practices to follow. – Abhishek Saha Oct 22 '12 at 05:33

score 0 · Answer 5 · answered Oct 22 '12 at 05:13

0

its a good practice to make php files without the closing tag:

?>

just write something like:

//end of file

you can see it for example in codeIgniter php files

answered Oct 22 '12 at 05:13

Rustam Kichinsky

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1
7

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WHY??? I disagree with this unsourced claim!!! – John Dvorak Oct 22 '12 at 05:15
because after the closing php tag may be some whitespaces, that is the only reason – Rustam Kichinsky Oct 22 '12 at 05:16
you mean, "you have to choose between malformed PHP, breaking the UNIX convention and having to `ob` any includes before headers"? Still a good point. I vote for #2 - breaking the UNIX convention. – John Dvorak Oct 22 '12 at 05:20
@JanDvorak What UNIX convention do you speak of? – Ja͢ck Oct 22 '12 at 05:29
@jan: that's a recommendation by ramus. ;-) – itachi Oct 22 '12 at 05:30
@itachi who is ramus? Link please – John Dvorak Oct 22 '12 at 05:31
maybe Rasmus Lerdorf? :), i just readed about that in codeigniter documentation, thats all) – Rustam Kichinsky Oct 22 '12 at 05:32
@Jack the convention of ending all text files with a newline, dating back to the times when the unix progams were as stupid as possible meaning they would not insert the newline for you when listing the file. – John Dvorak Oct 22 '12 at 05:34

score 0 · Answer 6 · edited May 23 '17 at 12:04

0

same question/problem

try to add ob_start() at start and ob_flush() or ob_end_flush() at end

edited May 23 '17 at 12:04

Community

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1

answered Oct 22 '12 at 05:14

Pragnesh Chauhan

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score 0 · Answer 7 · answered Oct 22 '12 at 05:17

0

Try to use

<?php ob_start();?> // top of the page

<?php ob_flush();?> // at the end of the page

these two are used to start the output buffer. if we use this the output to the user will throw only after the exicution of each line in that document

and try to remove the space before session_start().

eg: <?php session_start();?>
    <!DOCTYPE html>
    <html>

answered Oct 22 '12 at 05:17

Nevin

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buffering the entire script is bad for your performance. – John Dvorak Oct 22 '12 at 05:22
yea. i know that. but its help me a lot when the redirection problem arise. And i didt get any other way. – Nevin Oct 22 '12 at 05:25

PHP Header Already Sent Error

7 Answers7