Init 5

Pubsub is one of the most recognizable patterns in computer science, employed as a simple solution to a wide range of problems, with different implementations.

Many times I’ve found myself in need of an access to my machine at work for quick’n dirty hacks, but something went wrong with the VPN settings

UPDATE: 2020-02-07

In the previous 6 parts we explored a fair amount of common CS topics such as networks and data structures, the little journey ended up with a bugged but working toy to play with.

This part will focus on the implementation of the handlers, they will be mapped one-on-one with MQTT commands in an array, indexed by command type, making it trivial to call the correct function depending on the packet type.

In the Part 4 we explored some useful concepts and implemented two data structures on top of those concepts.

Before proceeding to the implementation of all command handlers, we’re going to design and implement some of the most common data structures needed to the correct functioning of the server, namely hashtable, list and a trie.

This part deal with the implementation of the server part of our application, by using the network module we drafted on part-2 it should be relative easy to handle incoming commands from a MQTT clients respecting 3.1.1 standards as we defined on part 1.

Let’s continue from where we left, in the part 1 we defined and roughly modeled the MQTT v3.1.1 protocol and our src/mqtt.c module has now all unpacking functions, we must add the remaining build helpers and the packing functions to serialize packet for output.

It’s been a while that for my daily work I deal with IoT architectures and research best patterns to develop such systems, including diving through standards and protocols like MQTT;

I’ve never been a great planner for my life, I can safely say that the only planning which I usually make is strictly bound to the life cycle of software, well, sometimes not even there to be fair, but now I’m trying to face this issue or at least marginally improve in this aspect.

I did it! Finally, after years of procrastination and unmaintained self-promises I’m here at almost 2 AM writing the mandatory hello world to the chaotic internet sea.