Goodies

This forder contains useful stuff.

Keymap: italyprog.zip

This is an enhanced keyboard map for italian keyboards that adds two shortcuts for characters that are often used in programming and on linux: tilda ~ and backtick `.

Those characters are mapped to AltGR + ' and AltGr + ì, respectively.

NOTE: this is only needed if you have a physical italian keyboard

To install it, proceed as follows:

1. unzip
2. run the installer setup.exe
3. Go to Settings > Time & language > Language & region, then click on the dots beside your language (Italian), then under the section "keyboard" click on "Add a keyboard" and search for "Italian - Programmer keys"
4. optionally, remove the original italian keymap

MQTT

Running the broker

The MQTT protocol requires a broker to be running. We are going to use the broker mosquitto, which is a very popular and lightweight broker. On Linux, it runs as a service.

Nowadays, the most powerful and safe way for running services is to use Docker containers. So, in the first place, and regardless your operating system, you must install Docker. For Windows, you can download the installer from here. For Linux, you can follow the instructions here. For MacOS, you can follow the instructions here.

Once Docker is installed, the MQTT broker can be launched using the Docker container eclipse-mosquitto. So, open the terminal in this folder and type:

docker run -it --rm -p1883:1883 -v"${PWD}/mosquitto.conf:/mosquitto/config/mosquitto.conf" eclipse-mosquitto

Note that that the mosquitto.conf file must be in the current directory.

As a shortcut, you can simply run the script run_mosquitto.sh in this folder:

./run_mosquitto.sh

Once you are done, you can stop the broker with the following DOcker command:

docker stop mosquitto

Installing libmosquitto on Linux

We are going to build a client for the MQTT broker. To do so, we are using a well-known library named libmosquitto. The library could be installed with the Ubuntu package manager as sudo apt install libmosquitto-dev. Unfortunately, this command installs a pretty old version of the library, version 1.6.9 at the time of writing, while the current version is 2.0.14.

Consequently, we are going to download the source of the latest version and compile it. Proceed as follows, in a WSL terminal:

cd ~
wget https://mosquitto.org/files/source/mosquitto-2.0.14.tar.gz
tar xzf mosquitto-2.0.14.tar.gz
cd mosquitto-2.0.14
cmake -Bbuild . -DCMAKE_BUILD_TYPE=Release -DWITH_TLS=OFF -DDOCUMENTATION=OFF -DWITH_LIB_CPP=OFF -DWITH_SRV=OFF -DWITH_CJSON=OFF
cmake --build build
sudo cmake --install build

Now you can verify that the installation went fine with the command:

mosquitto_sub --help

If you get an error with loading shared libraries (and only in this case!) do the following:

cat /etc/ld.so.conf.d/libc.conf

If the output does not contain the path /usr/local/lib, then type:

echo "/usr/local/lib" | sudo tee -a /etc/ld.so.conf.d/libc.conf

Then (and in any case, even if the previous command does report /usr/local/lib) type:

sudo ldconfig

Now it should work.

Installing libmosquitto on MacOS

On MacOS, libmosquitto can be easily installed with the command:

brew install mosquitto

and no further steps needed.