Janos

👋 Hi!

I’m a software engineer specializing in server applications and system-level software development, but sometimes I venture into the front end world too. Quite often I find myself taking a deep dive into a topic that tickles my brain.

When I’m not coding I like spending time outdoors, such as cycling, climbing. We are writing this blog together with my partner Sanja.

You can find most of my work on GitHub.

Getting started in Object-Oriented Programming

by

So, you’ve been programming for a while, and you are still stumped with what object-oriented programming actually is? Then this may be the guide for you. We’ll take a departure from traditional explanations and look at a new way of explaining OOP.

Introduction to SQL databases Part 2

by

In the previous episode of our journey we have spoken about the basics of writing an SQL query. However, we did not speak of the limitations you can place on SQL tables.

Introduction to SQL databases Part 1

by

Whether you are running a web app, a financial system or a game, you need some method of storing your data. SQL allows you to query most traditional databases, like MySQL or PostgreSQL. Let’s take a look.

What is the CAP theorem?

by

The CAP theorem is one of the most fundamental principles of distributed system design. Yet, it is often misunderstood or outright disregarded.

Filtering spam with Exim and Spamassassin (properly)

by

SpamAssassin is a frequently used companion for Exim. However, most people set it up in a synchronous manner – spam is checked directly when the SMTP session is opened. While this is certainly a valid technique, it has it’s drawbacks. It leaves the server vulnerable to DOS attacks because the spam filtering is a big resource hog. Having SpamAssassin headers in the mail from the remote servers is also an issue, because the $h_X-Spam-* variables will start misbehaving suddenly.

Fixing RDNS_NONE with Spamassassin

by

When dealing with SpamAssassin and Exim, one may often encounter a mysterious RDNS_NONE

Proper time handling with PHP and MySQL

by

Few developers actually know that not only character encodings but also time handling can cause you headaches when it comes to PHP and MySQL. Contrary to popular belief, PHP’s time handling actually works quite reasonably if you know how time actually works. If you don’t, you may be in for a big surprise when you add 3 days to a date and end up with a date 4 days from now. The answer lies within the *NIX time handling.

Setting up Apache with PHP-FPM

by

Nowadays nginx seems to experience a serious growth in terms of numbers when looking at HTTP server software. Almost all articles regarding PHP-FPM detail the setup with nginx, very few talk about the good old Apache HTTPd. Admittedly, it’s a little harder to set up due to the myriad hacks layered in it’s internal infrastructure. It has one major advantage however: it handles .htaccess files which allows customers to configure their own little corner of the webserver without poking the admin or endangering the server’s stability.

Don't use FTP — Here's why

by

FTP has been around since the early days of the internet. Even though it’s old and cranky a lot of sysadmins, especially those just getting into managing a server, still don’t know anything else. FTP is outdated, has a lot of problems and sometimes it can be outright dangerous, however it’s wide spread acceptance as an easy way for transferring files makes it hard to switch to alternative protocols. If you have a choice, don’t use it. I’ll show you why.