Question

I’m using a callback to validate URLs submitted by a text input. I need to insert NULL in the database if the text input is empty (meaning the user erased his/her URL entry). I’m trying the code below but it just inserts an empty string in the database.

$this->form_validation->set_rules('image_url', 'Image URL', 'trim|xss_clean|prep_url|callback__validate_url');

The callback:

    function _validate_url($str)
    {
        if (isset($str))
        {
            $pattern = "/^(http|https):\/\/([A-Z0-9][A-Z0-9_-]*(?:\.[A-Z0-9][A-Z0-9_-]*)+):?(\d+)?\/?/i";
            if (!preg_match($pattern, $str))
            {
                $this->form_validation->set_message('_validate_url', 'URL is not valid');
                return FALSE;
            }
            else 
            {
                if (!isset($str)) //if input empty
                {
                    return NULL; //return NULL to input?
                }

                return TRUE;
            }
        }

        return TRUE; 
    }

How can I return a value to the input via a callback?

Update:

The code above is wrong and I was not able to return NULL in the input (I’m guessing because its returns a string) so I did it outside the callback

   $image_url = $this->input->post('image_url');

    if (empty($image_url)) 
    { 
         $image_url = NULL; 
    }

    $data = array (
            'content' => $this->input->post('content'),
            'image_url' => $entry_image_url
    );

    //add to database 

Answer 1

Look at this piece of code, it’s got an impossible condition:

    if (isset($str)) // Everything in this block runs if $str is "set"
    {
        if (!preg_match($pattern, $str))
        {
            //
        }
        else 
        {
            if (!isset($str)) // But you're checking if $str is not set....
            {
                // This can never happen!
            }

        }
    }

Replace that condition with an appropriate way to check if the input is empty, perhaps check if trim($str) === '' or even empty($str).