problem:

[Muneeb1998]

i face error when i deploy CodeIgniter 4 project on hosting
CRITICAL - 2020-09-26 07:18:24 --> ini_set(): Headers already sent. You cannot change the session module's ini settings at this time
#0 [internal function]: CodeIgniter\Debug\Exceptions->errorHandler(2, 'ini_set(): Head...', '/home/p...', 43, Array)
#1 /home/mlnacta/public_html/habib_site/app/Controllers/BaseController.php(43): ini_set('session.save_pa...', '')
#2 /home/mlnacta/public_html/habib_site/vendor/codeigniter4/framework/system/CodeIgniter.php(891): App\Controllers\BaseController->initController(Object(CodeIgniter\HTTP\IncomingRequest), Object(CodeIgniter\HTTP\Response), Object(CodeIgniter\Log\Logger))
#3 /home/mlnacta/public_html/habib_site/vendor/codeigniter4/framework/system/CodeIgniter.php(399): CodeIgniter\CodeIgniter->createController()
#4 /home/mlnacta/public_html/habib_site/vendor/codeigniter4/framework/system/CodeIgniter.php(312): CodeIgniter\CodeIgniter->handleRequest(NULL, Object(Config\Cache), false)
#5 /home/mlnacta/public_html/habib_site/index.php(44): CodeIgniter\CodeIgniter->run()
#6 {main}
CRITICAL - 2020-09-26 07:18:24 --> Uncaught ErrorException: Cannot modify header information - headers already sent by (output started at /home/mlnacta/public_html/habib_site/app/Config/Events.php:27) in /home/mlnacta/public_html/habib_site/vendor/codeigniter4/framework/system/Debug/Exceptions.php:164
Stack trace:
#0 [internal function]: CodeIgniter\Debug\Exceptions->errorHandler(2, 'Cannot modify h...', '/home/p...', 164, Array)
#1 /home/mlnacta/public_html/habib_site/vendor/codeigniter4/framework/system/Debug/Exceptions.php(164): header('HTTP/1.1 500 In...', true, 500)
#2 [internal function]: CodeIgniter\Debug\Exceptions->exceptionHandler(Object(ErrorException))
#3 {main}
thrown
#0 [internal function]: CodeIgniter\Debug\Exceptions->shutdownHandler()
#1 {main}

[michalsn]

1. What CodeIgniter version are you using?
2. Can you check if you have a line if (ini_get('zlib.output_compression')) in your app/Config/Events.php file?

[Muneeb1998]

1. What CodeIgniter version are you using?
2. Can you check if you have a line if (ini_get('zlib.output_compression')) in your app/Config/Events.php file?

1. i am using 4.0.4 version
2. no

[paulbalandan]

It seems your code in BaseController is throwing errors when setting the session path. Can you paste the contents of your BaseController?

[Muneeb1998]

`<?php
namespace App\Controllers;

/**

• Class BaseController
• BaseController provides a convenient place for loading components
• and performing functions that are needed by all your controllers.
• Extend this class in any new controllers:

• class Home extends BaseController
  

• For security be sure to declare any new methods as protected or private.
• @Package CodeIgniter
  */

use CodeIgniter\Controller;
// JAK Cutom:
use App\Libraries\App;
// JAK Cutom;

class BaseController extends Controller
{

/**
 * An array of helpers to be loaded automatically upon
 * class instantiation. These helpers will be available
 * to all other controllers that extend BaseController.
 *
 * @var array
 */
protected $helpers = [];

/**
 * Constructor.
 */
public function initController(\CodeIgniter\HTTP\RequestInterface $request, \CodeIgniter\HTTP\ResponseInterface $response, \Psr\Log\LoggerInterface $logger)
{
	// Do Not Edit This Line
	parent::initController($request, $response, $logger);

	//--------------------------------------------------------------------
	// Preload any models, libraries, etc, here.
	//--------------------------------------------------------------------
	// E.g.:.
	$this->session 	= \Config\Services::session();
	if(isset($_GET['lang'])){
		$this->session->set(array(
			'lang' => $_GET['lang']
		));
	}
	// else{
	// 	$this->session->set(array(
	// 		'lang' => 'English'
	// 	));
	// }
	// print_r($_SESSION['lang']);
	// $r = (explode('/', uri_string(), 2));
	// JAK Cutom:
	$this->libraryApp 	= new App($this);
	helper('front');
	// JAK Cutom;
}

}
`

[enix-app]

I guess these line:

$this->libraryApp = new App($this);
helper('front');

I don't know what's in it.

[michalsn]

From your answer I see you upgraded to 4.0.4 from lower version, so you don't have a check against zlib.output_compression in place.

It's either the wrong sessionSavePath or enabled zlib.output_compression extension.

I will close this since the problem occurs only on your production server, but if none of the suggestions solve the problem, please feel free to continue the conversation.