laravel 5.1 form validation with foreach

Question

In my app administrator can add categories , and subcategories . Each category/subcategory has an id , name and slug . Then the user can add an article and select if she wants to add a category and/or subcategory to that user.

This is done through input forms which looks like this

O - Add category 1 subcategories
O - Add category 2 subcategories

Where O are checkboxes. Clicking on O - add category x subcategories will open list of subcategories as:

O - Add category 1 subcategories
 ----O - 1st subcat
 ----O - 2nd subcat
 ----O - 3rd subcat
O - Add category 2 subcategories
 ----O - 1st subcat
 ----O - 2nd subcat
 ----O - 3rd subcat

input id's are as category1slug[subcategory1slug] , category1slug[subcategory2slug] , and so on. They are rendered in a form with foreach loop as

foreach ( $categories as $category) { input field }

Now I want to validate these entries as follows. If O - Add category 1 subcategories field is selected I want at least one of the subcategories to be selected. The custom validation I have done is here:

Laravel 5.1, nested validation

However I don't know how to apply it to all of the categories. I want to get the validation as follows:

'category1slug' => 'required_with_one_of:category1slug.subcategory1slug,category1slug.subcategory2slug,category1slug.subcategory3slug',
'category2slug' => 'required_with_one_of:category2slug.subcategory3slug,category2slug.subcategory4slug,category2slug.subcategory5slug',
'category3slug' => 'required_with_one_of:category3slug.subcategory6slug,category3slug.subcategory7slug,category3slug.subcategory8slug',

but I don't want to have to add them manually every time since the data is already in the database. Also if I had to add them manually I would have to descend to routes.php every time an admin adds new category or subcategory or when he changes subcategory/category relation.

Answer 1

in Request file there is

public function rules()
{ 
  return [];
}

which returns array. Return array as:

public function rules()
{ 
  $therulesarray = [];

  foreach ( $categories as $category) { 
    //desired logic here
    $therulesarray['attribute'] = 'rulestoapply'; //this will add new element in $therulesarray that our function rules() returns;
  }
  return $therulesarray;
}

Some more info: http://ericlbarnes.com/laravel-array-validation/