Here are my notes on how to retrieve, compile and configure Mosquitto with Websockets on Mint 18. I would imagine though this could work on Ubuntu or other Mint versions.
sudo apt-get install build-essential libc-ares-dev uuid-dev
sudo apt-get install libwebsockets-dev
Get the version that you prefer by changing the tar.gz file name below
wget http://mosquitto.org/files/source/mosquitto-1.4.10.tar.gz
tar xvzf mosquitto-1.4.10.tar.gz
cd mosquitto-1.4.10/
nano config.mk
# Build with websockets support on the broker.
WITH_WEBSOCKETS:=yes
make
sudo make install
sudo adduser mosquitto
sudo mosquitto_passwd -c /etc/mosquitto/pwfile mosquitto
sudo /etc/mosquitto/mosquitto.conf
# =================================================================
user mosquitto
# =================================================================
listener 1883
protocol mqtt
listener 9001
protocol websockets
# =================================================================
persistence true
persistence_location /var/lib/mosquitto/
# =================================================================
log_dest syslog
log_type error
log_type warning
log_type notice
log_type information
sudo /sbin/ldconfig
sudo mosquitto -c /etc/mosquitto/mosquitto.conf -v
Test the setup by using two additional shells one for each of the two commands below
mosquitto_sub -h localhost -t “greetings” -v
mosquitto_pub -h localhost -t “greetings” -m “hello”
NB The commands about do not test the websockets on port 9001 for which you would need to develop a Javascript test program or similar