Booking Handler

Description

This component is part of the the distributed system DENTISTIMO, a web application that offers a geolocalisation based dental care booking system. The booking handler takes care of requests regarding bookings. More details can be found in the component diagram in the documentation repository.

Component Responsibilities

• Listen to MQTT broker for booking data from front end
• Save booking to database
• Delete one booking from database
• Publish outcome of data maniuplation via mqtt

Data input and output

Data input

The component expects stringified json objects sent via MQTT.

The json objects should have at least these information for the following tasks:

• Save a new booking: a json object following the booking schema:

example

{   "name": "Peter",
"userID": {"$oid": "61a63f2b8a42f95c0b120a5a"},
"clinicID": {"$oid": "61a63f2b8a42f95c0b120a5a"},
"date": "23/12/2019",
"startTime": "9:00",
"endTime": "8:00",
}

• Delete a booking: the booking database id
• Retrieve a booking from the database: the booking database id
• Retreive all bookings of a given customer: the customer database id

example

{ "_id": {
        "$oid": "61a63f2b8a42f95c0b120a5a"
        },
    ...
}

Data output

The component sends stringified json objects. The format varies based on the request:

• Save a new booking: a stringified json object of the saved booking data:
• Delete a booking: a stringified json object of the deleted booking data
• Retrieve a booking from the database: a stringified json object of the saved booking data
• Retreive all bookings of a given customer: a collection of stringified json objects having of a same customer

Installing and running

Prerequisits

MQTT

You need to have a running version of MQTT on your machine. Please refer to this link to download the mosquitto broker if you do not have any.

Node.js

To download the latest version of node.js, please follow this link

Instructions

Step	Command
Start your MQTT broker on port 1883	This differs based on which broker, as well as your settings. Make sure the broker listens to port 1883. (Default port with mosquitto)
Clone this project on your machine	git clone < SSH address or HTTPS address >
Go to the repo and add .env file	Please contact one of the developers of this project to recieve the contents of the file. It should be placed directly in the repo.
Install necessary dependencies by running the following	npm install
Start the system from the repo by running the following	npm start

In the window of your broker, you should see a message similar to this:

1638885841: New client connected from 127.0.0.1:49531 as Dentistimo Team5 - Booking Handler n°3c1ff99e (p2, c1, k60).

The booking handler is now ready to proceed your requests.

Closing/unsubscribing

When starting the component using npm start, the following message will appear in the terminal:

To unsubscribe, simply follow the commands specified in terminal: xand then press enter