Add length rule: "The :attribute must must have an exact length of :length"

src/Rules/Length.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace Rakit\Validation\Rules;
+
+use Rakit\Validation\Rule;
+
+class Length extends Rule
+{
+    use Traits\SizeTrait;
+
+    /** @var string */
+    protected $message = "The :attribute must must have an exact length of :length";
+
+    /** @var array */
+    protected $fillableParams = ['length'];
+
+    /**
+     * Check the $value is valid
+     *
+     * @param mixed $value
+     * @return bool
+     */
+    public function check($value): bool
+    {
+        $this->requireParameters($this->fillableParams);
+
+        $this->requireParameters($this->fillableParams);
+
+        $length = (int) $this->parameter('length');
+
+        return strlen((string) $value) == $length;
+    }
+}

src/Validator.php

@@ -162,6 +162,7 @@ protected function registerBaseValidators()
             'defaults'                  => new Rules\Defaults,
             'default'                   => new Rules\Defaults, // alias of defaults
             'nullable'                  => new Rules\Nullable,
+            'length'                    => new Rules\Length,
         ];
 
         foreach ($baseValidator as $key => $validator) {