ansaurus

Question

Answer 1

+7 A:

Between your two PHP tags you have whitespace.

?>

<?php

This'll cause your headers to be sent before starting any session and sending more headers.

I suggest just removing that bit of code.

Mikee 2010-10-12 16:10:36

I love ya buddy

Matthew Carter 2010-10-12 17:00:58

Answer 2

+8 A:

the problem is between lines 16 and 18:

?>

<?php

this will write some whitespace (and send headers)

Yossarian 2010-10-12 16:11:00

I love ya buddy

Matthew Carter 2010-10-12 17:01:26

Answer 3

A:

ob_clean();

Add the above before the offending code. Cleans the buffer or something.

If you would have googled for it http://www.google.co.in/search?q=Warning%3A+session_register%28%29+[function.session-register]%3A+Cannot+send+session+cache+limiter+-+headers+already+sent the first result has the solution which says

make sure you have added ob_start(); at the first line of webpage and ob_end_flush(); at the end of webpage //i have used ob_end_clean() or ob_clean() in a similar case

Update:

I was downvoted. So let me clarify.

In the code in question , the space between the php tags was seen clearly and so the solution was straightforward. However, if the question in issue was not that simple, perhaps it was a include file which was problematic. What if the code ran into reams and reams before generating a space or other output and you couldn't track it? What if?

If you enclose stuff you do not want output for between ob_start() and ob_end_clean(). The output is not sent. ob_clean() does something similar.

Update 2 As Col. Shrapnel said

Never gag an error

Soultion: Remove the offending space.

Update for @meagar

While the answer to this problem should be removal of the space, I am posting a solution for the problem using, ob_clean() just for the upvote(I hate downvotes! :))

<?php
ob_start(); //started buffering
?>
Hello World and other dangerous texts
<?php 
if (isset($_SESSION['mattyc-admin'])){
    header ('Location: admin/home.php');
}

if (!isset($_GET['me'])){
    header ('Location: http://www.stat-me.com/mattyc');
}

if ($_GET['me'] != 'mattyc'){
    header ('Location: http://www.stat-me.com/mattyc');
}

?>

<?php
if ($_POST['name'] != "" && $_POST['password'] !="") {

//require "../../scripts/connect_to_mysql.php";

$name = $_POST['name'];
$pass = $_POST['password'];

$name = strip_tags($name);
$pass = strip_tags($pass);
//$name = mysql_real_escape_string($name);
//$pass = mysql_real_escape_string($pass);
$name = eregi_replace("`", "", $name);
$pass = eregi_replace("`", "", $pass);

//$pass = md5($pass);
ob_clean(); //can use ob_end_clean() too
if ($name == 'mattyc' && $pass == 'qwerty'){
    if (isset ($_SESSION['mattyc-admin'])){
        header ('Location: admin/upload.php');
    }else{
     session_register('mattyc-admin'); 
     $_SESSION['mattyc-admin'] = ('mattyc-adminp');
     header ('Location: admin/upload.php');
    }
}

}
?>

With output buffering set to Off in my php.ini, I tested the above code. Just add ob_start to the start of the page. ob_clean() is only needed to end buffering. If you are sure that the page will show no output and only redirect then ob_clean is not needed too. (Otherwise use ob_clean() before the problematic code segment.) Thanks to @meagar for the code and inspiration.

abel 2010-10-12 17:02:28

When you downvote please comment. Thats convention.

abel 2010-10-12 17:34:30

output buffering is a tool with it's own purpose. do not use it as a crutch to cover bad design/simple mistake. Never gag an error. But always repair it.

Col. Shrapnel 2010-10-12 17:50:46

@Col. Shrapnel Thank you. and I completely agree. But it has saved me on one ocassion when using TCPDF which does not tolerate any output before the pdf header are sent.

abel 2010-10-12 18:00:45

I down-voted your answer because it is wrong. Adding `ob_clean` "before the offending code" won't fix the problem, that's now how output buffering works. It doesn't "clean the buffer or something". That kind of language confuses your answer and makes it look like you have no idea what you're talking about.

meagar 2010-10-12 18:13:05

@meagar See my rep and look at my profile(I am a PHP beginner). Actually I didnt know what it did exactly. I read up the manuals and I had used it before. Thats the reason I posted.

abel 2010-10-12 18:20:02

+1. Output buffering will save you a lot of pain. Do your best to remove premature output, but output buffer anyway so that your application is less fragile when someone does inevitably introduce an issue.

Frank Farmer 2010-10-12 18:20:43

@Frank First, that's terrible advice. You're saving yourself pain by encouraging sloppy, inefficient practices.Secondly, this answer is demonstratively wrong, regardless of your feelings about output buffering. It doesn't deserve an up-vote until it's at least correct.

meagar 2010-10-12 18:24:21

@abel If you don't know what something does, you probably shouldn't be suggesting it as an answer. You took a guess, and answered incorrectly, so I downvoted. I'm not trying to be mean, this is what downvoting is for. If you fix your answer so it's actually correct, I will remove my vote.

meagar 2010-10-12 18:28:26

@meagar very true. i should have tested the code before i put up an answer. I did that now and I find the code works(redirects) without an error even with the space in place. know why? Apache 2.2.11 , PHP 5.3.0

abel 2010-10-13 08:39:50

@abel The error only occurs if any of the `header` calls after `?><?php` execute. The first three calls work fine as they occur before any output. The issue is, once that space is output, subsequent calls to `header()` will raise an error.

meagar 2010-10-13 13:20:16

@meagar I added a Hello World to the top of the page. The page still redirected

abel 2010-10-13 13:38:34

@abel You likely have output buffering enabled; checkout your `output_buffering` setting in php.ini, and try setting it to `output_buffering = Off;`

meagar 2010-10-13 13:59:54

@meagar just checked it is set to on. and it says default is off. any disadvantage leaving it on?

abel 2010-10-13 14:53:45

@abel Only what we talked about in these comments: Leaving it on covers up logic errors that you would otherwise be aware of. While it's good that you don't have to worry about extraneous output before calls to `header()`, I would rather address those errors than suppress them.

meagar 2010-10-13 14:57:29

@meagar I have posted a working code sample. Should not be the preferred solution.

abel 2010-10-14 13:05:37

ansaurus

tags:

views:

answers:

PHP headers already sent problem

related questions