Laravel Request Parameter Filtering: Remove request parameters not defined in the request ruleset, if there is one. Returns false if parameters were attempted, but none were permitted.

Request.php

<?php

namespace App\Http\Requests;

class Request extends FormRequest
{
    /**
     * @return bool
     */
    public function filterFields()
    {
        //Dot notation makes it possible to parse nested values without recursion
        $original = array_dot($this->all());
        $filtered = [];
        
        //If there are no rules, accept any input
        $rules = collect($this->rules());
        if ($rules->isEmpty()) {
            return true;
        }
        
        //Make room for tokens being placed as a URL query parameter, and Fractal includes
        $exceptions = [
            self::TOKEN_NAME => 'string',
            self::INCLUDE_NAME => 'string',
            camel_case(self::ADMIN_TOKEN_NAME) => 'string',
            snake_case(self::ADMIN_TOKEN_NAME) => 'string'
        ];
        $keys = $rules->keys()->merge(array_keys($exceptions));
        $rules = $rules->merge($exceptions);
        
        $rules->each(function ($rules, $key) use ($original, $keys, &$filtered) {
            //Allow for array or pipe-delimited rule-sets
            if (is_string($rules)) {
                $rules = explode('|', $rules);
            }
            //In case a rule requires an element to be an array, look for nested rules
            $nestedRules = $keys->filter(function ($otherKey) use ($key) {
                return (strpos($otherKey, "$key.") === 0);
            });
            //If the input must be an array, default missing nested rules to a wildcard
            if (in_array('array', $rules) && $nestedRules->isEmpty()) {
                $key .= ".*";
            }
            
            foreach ($original as $dotIndex => $element) {
                //fnmatch respects wildcard asterisks
                if (fnmatch($key, $dotIndex)) {
                    //array_set respects dot-notation, building out a normal array
                    array_set($filtered, $dotIndex, $element);
                }
            }
        });
        
        //Replace all input values with the filtered set
        $this->replace($filtered);
        
        //If field changes were attempted, but non were permitted, false here may indicate a 403 if used in authorize()
        return (empty($original) || !empty($this->all()));
    }
}