Question

I have a problem in CodeIgniter, and that is that when an image is not found on the server, the instance of a controller is created (besides the one that called the view).

I know all this can sound confusing, so this is the code to observe what I’m saying. I did this changes to a clean 2.1.0 CI version:

Add a controller to override the 404 error page, I added this one:

// add application/controllers/Errors.php 
Class Errors extends CI_Controller {

    public function error_404() {
        echo 'error';
    }
}
// change routes.php
$route['404_override'] = 'Errors/error_404';

Use a controller that isn’t the default one with an unexisting image, I used this:

// add application/controllers/Foo.php 
Class Foo extends CI_Controller {

    public function index() {
        echo '<img src="doesntexist.png" />';
    }

}

I couldn’t figure out another way of debugging it, so I created a log to write the events on CodeIgniter.php:

// add on CodeIgniter.php line 356
$path = 'log.txt'; //Place log where you can find it
$file = fopen($path, 'a');
fwrite($file, "Calling method {$class}/{$method} with request {$_SERVER['REQUEST_URI']}\r\n");
fclose($file);

With this, the log that generates visiting the index function is the following:

Calling method Foo/index with request /test/index.php/Foo
Calling method Errors/error_404 with request /test/index.php/doesntexist.png

Which is the problem I have, an instance of the Error class is created.

Answer 1

that is that when an image is not found on the server, the instance of a controller is created 

Not really. What I believe is happening is that, since you’re using a relative path for the image (and calling it directly inside a controller, which is wrong because you’re ouputting something before headers), your browser attach the image directly to the CI url, thus making this request to the server:

index.php/doesntexist.png

Which is (correctly) interpreted by CI as a request to a controller, which doesn’t exists, and therefore it issues the error class.

You could do, in your actual code (I’d put the images in a view, though):

echo '<img src="/doesntexist.png" />'

using an absoluth path, or using the base_url() method from the url helper:

echo '<img src="'.base_url().'doesntexist.png" />

This should tell the server to fetch the right request (/test/doesntexist.png) and won’t trigger that error.