topic_selector.py

###############################################
#
# Author: Aniruddha Gokhale
# Vanderbilt University
#
# Purpose:
# This is an example showing a list of pre-defined topics from which publishers
# and subscribers can choose which ones they would like to use for publication
# and subscription, respectively.
#
# To be used by a publisher or subscriber application logic only. See their code
#
# Created: Spring 2023
#
###############################################

# since we are going to publish or subscribe to a random sampling of topics,
# we need this package
import random

# define a helper class to hold all the topics that we support in our system


class TopicSelector ():

    # some pre-defined topics from which a publisher or subscriber chooses
    # from. Feel free to extend it or completely change these. All up to you.
    # I am providing some initial starter capabilitiy.
    #
    # Say these are a list of all topics that are published.
    topiclist = ["weather", "humidity", "airquality", "light",
                            "pressure", "temperature", "sound", "altitude",
                            "location"]

    # return a random subset of topics from this list, which becomes our interest
    # A publisher or subscriber application logic will invoke this method to get their
    # interest.
    def interest(self, num=1):
        # here we just randomly create a subset from this list and return it
        # return random.sample (self.topiclist, random.randint (1, len (self.topiclist)))
        return random.sample(self.topiclist, num)

    # generate a publication on a given topic
    def gen_publication(self, topic):
        if (topic == "weather"):
            return random.choice(["sunny", "cloudy", "rainy", "foggy", "icy"])
        elif (topic == "humidity"):
            return str(random.uniform(10.0, 100.0))
        elif (topic == "airquality"):
            return random.choice(["good", "smog", "poor"])
        elif (topic == "light"):
            # in lumens
            return random.choice(["450", "800", "1100", "1600"])
        elif (topic == "pressure"):
            # in millibars (lowest recorded to highest recorded)
            return str(random.randint(870, 1084))
        elif (topic == "temperature"):
            # in fahrenheit
            return str(random.randint(-100, 100))
        elif (topic == "sound"):
            # in decibels
            return str(random.randint(30, 95))
        elif (topic == "altitude"):
            # in feet
            return str(random.randint(0, 40000))
        elif (topic == "location"):
            return random.choice(["America", "Europe", "Asia", "Africa", "Australia"])