Added common random string generation routine.

src/XString.php

@@ -5,10 +5,19 @@
 
 namespace Index;
 
+use InvalidArgumentException;
+
 /**
  * Provides various helper methods for strings.
  */
 final class XString {
+    /**
+     * Default character set for the random method.
+     *
+     * @var string
+     */
+    public const RANDOM_CHARS = 'AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz0123456789';
+
     public static function toBool(string $value): bool {
         return boolval($value);
     }
@@ -55,4 +64,26 @@ final class XString {
             return true;
         return empty(trim((string)$string));
     }
+
+    /**
+     * Generates a random string of user specified length.
+     *
+     * @param int $length Desired length of the string.
+     * @param string $chars Set of characters to pick from. Default set contains the alphabet in upper- and lowercase and numbers 0 thru 9.
+     * @return string The generated string.
+     */
+    public static function random(int $length, string $chars = self::RANDOM_CHARS): string {
+        if($length < 1)
+            throw new InvalidArgumentException('$length must be at least 1.');
+        if($chars === '')
+            throw new InvalidArgumentException('$chars may not be empty.');
+
+        $string = '';
+        $count = strlen($chars) - 1;
+
+        while($length-- > 0)
+            $string .= $chars[random_int(0, $count)];
+
+        return $string;
+    }
 }