session_start() [function.session-start] (What is this error?)

[billy_111]

Hey,

I am getting an error on one of my website pages. If you take a look at this link:-

http://www.judgethejob.com/vinny/join-us/

You will i get this error:-

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /domains/judgethejob.com/http/vinny/join-us/index.php:11) in /domains/judgethejob.com/http/vinny/join-us/index.php on line 204

Now, i have the following code and i have ob_start which i thought would prevent this error..?

         <?php
            session_start();
            ob_start();
            
            if (isset($_POST['btn-submit'])) 
            {     
                include("../conn.php");
                
                $emailcheck = $_POST['txt_email'];
                
                $email_check = mysql_query("SELECT email FROM tbl_members WHERE email = '$emailcheck'") or die(mysql_error());
                $email_check2 = mysql_num_rows($email_check);
                                
                if ($email_check2 != 0) {
                echo "<p>Sorry, the email '".$_POST['txt_email']."' is already in use. <a href='javascript:history.go(-1)'> Return</a> to amend.</p>";
                }
                else 
                {
                $insert = "INSERT INTO tbl_members(username, password, email, gender, postcode, DOB, education, date_added) VALUES 
                (
                                // Insert here...
                )";
                $add_member = mysql_query($insert);
                
                $from = "ibrar@freemanholland.com";
                $headers = "From: $from";
                $to = $_POST['txt_email'];
                $subject = "This is a test";
                $body = "Thank you for registering with Judge the Job. 
                One of our team will contact you within 24 hours about 
                your registration to confirm your details. If ok we will 
                make your account active and you will be able to place your 
                offer immediately. 
                
                Meanwhile please keep your login details safe: E-mail: ".$_POST['txt_email']." Password: ".$_POST['txt_password']."";
                //$body = "Thank you for registering on our website. Your login details are as follows:- Email Address: ".$_POST['txt_email']." and Username: ".$_POST['txt_username']."";
                
                if (mail($to, $subject, $body, $headers)) {
                  echo("<p>Many thanks for registering – one of our team will contact you within 24 hours about your registration to confirm your details. If ok we will make your account active and you will be able to place your offer immediately.</p>");
                 } else {
                  echo("<p>Message delivery failed... please try again later, or contact the administrator.</p>");
                 }
                }    
            }

How can i prevent this?

Regards

[Jake Arkinstall]

You need to make sure that NOTHING is sent to the browser before session_start is called. Output buffering to prevent it is usually a hack to overcome dodgy programming, so try and avoid that.

If your code snippet is anything to go by, you have whitespace before the opening PHP tag. That counts as sending something to the browser - therefore you can't start a session.

If you're outputting HTML or whatever before parsing this script, that will also cause this error. A simple solution would be to start the session in the main file, one that's always included - e.g. if you have a header file which outputs HTML before scripts are run, put the session start at the top of that. It may be your database connection file; any file which is included in the majority of pages and is run before anything is output.

Remove that space, see what happens.

[billy_111]

Thanks!

That worked i will keep that in mind for the future..

Regards

[ge0man]

Yes, nothing can be outputted to the browser before you do a session start or even a header redirect.

[BonyYousuf]

yeah i had the same problem session ... nothing can be passed not even a single whitespace before start_session()

[Dan Grossman]

In the way of background, what separates headers from content in an HTTP response is a single blank line. Once your script has any output, including whitespace, in order to print that output, PHP must send the blank line ending the headers. At that point, it's too late to start the session, since sessions are maintained through a cookie. Cookies are sent as HTTP headers, and any output after that blank line is interpreted by the browser as content rather than a header, so it can't be output at this point.