Laravel validation with custom condition

I'm trying to setup validation rule with condition but have no idea how to do following:

In my form I have title_url (array for multiple language versions). I want to have unique title_url but only when module_cat_id in the form has same value as existing rows in DB.

This is my rule:

'title_url.*'   => 'required|min:3|unique:modules_cat_lang,title_url'

Any ideas how to solve this?

Solution

You can define your custom similar to code below:

\Validator::extend('custom_validator', function ($attribute, $value, $parameters) {
        foreach ($value as $v) {
            $query = \DB::table('modules_cat_lang') // use model if you have
                ->where('title_url', $v)
                ->where('module_cat_id', \Input::get('module_cat_id'));
            if ($query->exists()) {
                return false;
            }
        }
    });
'title_url.*'   => 'required|min:3|custom_validator'