diskfloppy.me/app/Http/Controllers/GuestbookController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use DB;

class GuestbookController extends Controller {
    public function guestbook() {
        return view('pages.guestbook');
    }

    public function guestbookPost(Request $request) {
        $this->validate($request, [
            'name' => 'required',
            'message' => 'required'
        ]);

        $matching_bans = DB::select('SELECT reason FROM guestbook__bans WHERE ip_address = ?', array($request->ip()));

        if (!empty($matching_bans)) {
            return view('errors.guestbook-ipban')->with('reason', $matching_bans[0]->reason);
        }

        DB::insert(
            'INSERT INTO guestbook__entries (name, timestamp, ip_address, agent, message) values (?, ?, ?, ?, ?)',
            [
                htmlspecialchars($request->get('name')),
                time(),
                $request->ip(),
                $request->userAgent(),
                htmlspecialchars($request->get('message'))
            ]
        );

        return back()->with('success', 'Entry submitted successfully!');
    }
}