Codeigniter error message Cannot modify header information

Question

I got this error message when i run my php CodeIgniter project:

A PHP Error was encountered

Severity: Warning

Message: Cannot modify header information - headers already sent by (output started at C:\AppServ\www\tree\application\models\mtree.php:17)

Filename: core/Common.php

Line Number: 442

line 17:

echo $row->members_id . "</br>";

this is my model function:

function convert_all() {
    $this->db->empty_table('table1');
    $this->db->empty_table('table2');
    $this->db->query("INSERT INTO `table1` (`members_id`, `members_username`);
    $query = $this->db->get('table2');
    foreach ($query->result() as $row) {
        if ($row->members_id > 1) {
            echo $row->members_id . "</br>";
        }
        if ($this->isadvanced($row->members_id, $row->members_direct_id)) {
            $this->insert_to_right($row, $row->members_direct_id);
        } else {
            $this->insert_to_left($row, $row->members_direct_id);
        }
    }
}

Unrelated: You're missing quotes at the end of this statement: $this->db->query("INSERT INTO table1 (members_id, members_username); — Amal
– Amal, Commented Nov 20, 2013 at 12:34
Error caused by some content being sent to the user before the call to header function. The code you gave does not provide enough information to aid debugging. Read more about the error: php.net/manual/en/function.header.php — adeelx
– adeelx, Commented Nov 20, 2013 at 12:37
Take a look here stackoverflow.com/questions/8028957/headers-already-sent-by-php — Suvash sarker
– Suvash sarker, Commented Nov 20, 2013 at 12:39

linuxeasy · Accepted Answer · 2017-05-23 11:08:28Z

12

While using codeigniter, its best recommended that you echo only in views.

Echoing anywhere randomly sends some data to browser, after which you can't modify headers (this includes attempt to redirect, set content-type, etc)

You should re-organize your code, such that, echo are done within views only. This will solve your header issues in Codeigniter.

This also includes extra whitespaces at the end after the closing brace "} ?>" in non-view php files.

edited May 23, 2017 at 11:08

answered Nov 20, 2013 at 12:41

linuxeasy

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Comments

Lundin · Accepted Answer · 2017-09-18 15:01:07Z

1

I think it will be helpfull Use $config['sess_save_path'] = sys_get_temp_dir(); instead of $config['sess_save_path'] = NULL; in your Application/config/config.php file

edited Sep 18, 2017 at 15:01

Lundin

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answered Sep 18, 2017 at 14:39

MALIK KHAN

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YakovL · Accepted Answer · 2018-02-11 17:29:42Z

1

You can't display anything before the header function is called. You should not display anything form model or controller to avoid this kind of error. If you want to display something form the controller or model then you should store the output to the buffer instead of sending it to the browser. You can store the output to the buffer using ob_start() function before header() function is called. Then you can do something like this

if(true)
{
    header("Location:http://google.com");
}
else
{
   ob_end_flush();
}

edited Feb 11, 2018 at 17:29

YakovL

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answered Nov 20, 2013 at 13:04

Monir

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Comments

joemisika · Accepted Answer · 2014-02-04 14:47:20Z

0

this was your issue - echo $row->members_id . ""; -- as the above answers say, don't echo something in your controllers, push to do it in the views - always

answered Feb 4, 2014 at 14:47

joemisika

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