This method checks if an array key exists recursively and returns its value on existence. Optionally validates the value against a callable.

safeRecursiveArrayAccess.php

<?php
/**
 * This method checks if an array key exists recursively and returns its value on existence.
 * Optionally validates the value against a callable.
 *
 * Example without callable:
 * <code>
 * $myArray = [
 *      "foo" => [
 *          "bar" => [
 *              "blubb" => "my value"
 *          ]
 *      ]
 * ];
 *
 * $value = safeRecursiveArrayAccess($myArray, ["foo", "bar", "blubb"]);
 * var_dump($value); // string(8) "my value"
 * </code>
 *
 * Example with internal type-check functions:
 * <code>
 * $myArray = [
 *      "foo" => [
 *          "bar" => [
 *              "blubb" => "my value"
 *          ]
 *      ]
 * ];
 *
 * $value = safeRecursiveArrayAccess($myArray, ["foo", "bar", "blubb"], "is_array");
 * //Exception (blubb must be an array but string received)
 * </code>
 *
 * Example with callable validation:
 * <code>
 * $myArray = [
 *      "foo" => [
 *          "bar" => [
 *              "blubb" => "my value"
 *          ]
 *      ]
 * ];
 *
 * $value = safeRecursiveArrayAccess($myArray, ["foo", "bar", "blubb"], function($value) {
 *     // return true or false
 *     return myBusinessLogicValidation($value);
 * });
 * </code>
 *
 * @param array    $array the array you want to access
 * @param array    $path  an array of the keys to walk through recursively in the correct order
 * @param callable $validator
 *
 * @return mixed
 * @throws Exception
 */
public function safeRecursiveArrayAccess(array $array, array $path, callable $validator = null)
{
    foreach ($path as $key) {
        if (false === is_array($array)) {
            throw new Exception('The given Key does not exist: ' . $key);
        }

        if (array_key_exists($key, $array)) {
            $array = $array[$key];
        } else {
            throw new Exception('The given Key does not exist: ' . $key);
        }
    }

    if (!$validator) {
        return $array;
    }

    if (false === $validator($array)) {
        throw new Exception(sprintf(
            'Invalid Type detected, validated with %s, but received type of %s',
            $validator,
            gettype($array)
        ));
    }

    return $array;
}