Rewrite netcmd and ripe whois tools (#9724)

* Port RIPE whois to Laravel

* remove netcmd.php and port to laravel.
Escape CLI and set it to stream output live.

* fix browser buffer bust on a few browsers.

LibreNMS/Util/Validate.php

@@ -0,0 +1,54 @@
+<?php
+/**
+ * Validate.php
+ *
+ * -Description-
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @package    LibreNMS
+ * @link       http://librenms.org
+ * @copyright  2019 Tony Murray
+ * @author     Tony Murray <murraytony@gmail.com>
+ */
+
+namespace LibreNMS\Util;
+
+class Validate
+{
+    /**
+     * Checks if the give string is a valid hostname
+     * @param string $hostname
+     * @return boolean
+     */
+    public static function hostname($hostname)
+    {
+        // The Internet standards (Request for Comments) for protocols mandate that
+        // component hostname labels may contain only the ASCII letters 'a' through 'z'
+        // (in a case-insensitive manner), the digits '0' through '9', and the hyphen
+        // ('-'). The original specification of hostnames in RFC 952, mandated that
+        // labels could not start with a digit or with a hyphen, and must not end with
+        // a hyphen. However, a subsequent specification (RFC 1123) permitted hostname
+        // labels to start with digits. No other symbols, punctuation characters, or
+        // white space are permitted. While a hostname may not contain other characters,
+        // such as the underscore character (_), other DNS names may contain the underscore
+        // maximum length is 253 characters, maximum segment size is 63
+
+        return (
+            preg_match("/^([a-z\d](-*[a-z\d])*)(\.([a-z\d](-*[a-z\d])*))*\.?$/i", $hostname) //valid chars check
+            && preg_match("/^.{1,253}$/", $hostname) //overall length check
+            && preg_match("/^[^\.]{1,63}(\.[^\.]{1,63})*\.?$/", $hostname)
+        );
+    }
+}