stocklistener.py

# stocklistener.py
"""Visualizing a PubNub live stream."""
from matplotlib import animation
import matplotlib.pyplot as plt
import pandas as pd
import random 
import seaborn as sns
import sys
import keys

from pubnub.callbacks import SubscribeCallback
from pubnub.enums import PNStatusCategory
from pubnub.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub

import warnings
warnings.simplefilter(action='ignore', category=FutureWarning)

companies = ['Apple', 'Bespin Gas', 'Elerium', 'Google', 'Linen Cloth']

# DataFrame to store last stock prices 
companies_df = pd.DataFrame(
    {'company': companies, 'price' : [0, 0, 0, 0, 0]})
 
class StockSubscriberCallback(SubscribeCallback):
    """StockSubscriberCallback receives messages from PubNub."""
    def __init__(self, df, limit=1000):
        """Create instance variables for tracking number of tweets."""
        self.df = df  # DataFrame to store last stock prices
        self.order_count = 0
        self.MAX_ORDERS = limit  # 1000 by default
        super().__init__()  # call superclass's init

    def status(self, pubnub, status):
        if status.category == PNStatusCategory.PNConnectedCategory:
            print('Subscribed')
        elif status.category == PNStatusCategory.PNAcknowledgmentCategory:
            print('Unsubscribed')
 
    def message(self, pubnub, message):
        symbol = message.message['symbol']
        bid_price = message.message['bid_price']
        print(symbol, bid_price)
        self.df.at[companies.index(symbol), 'price'] = bid_price
        self.order_count += 1
        
        # if MAX_ORDERS is reached, unsubscribe from PubNub channel
        if self.order_count == self.MAX_ORDERS:
            pubnub.unsubscribe_all()
            
def update(frame_number):
    """Configures bar plot contents for each animation frame."""
    plt.cla()  # clear old barplot
    axes = sns.barplot(
        data=companies_df, x='company', y='price', palette='cool') 
    axes.set(xlabel='Company', ylabel='Price')  

if __name__ == '__main__':
    sns.set_style('whitegrid')  # white background with gray grid lines
    figure = plt.figure('Stock Prices')  # Figure for animation

    # set up pubnub-market-orders sensor stream key
    config = PNConfiguration()
    config.subscribe_key = 'sub-c-99084bc5-1844-4e1c-82ca-a01b18166ca8'
    config.user_id = keys.pubnub_user_id # new requirement in SDK 6.x
    
    # create PubNub client and register a SubscribeCallback
    pubnub = PubNub(config) 
    pubnub.add_listener(
        StockSubscriberCallback(df=companies_df, 
            limit=int(sys.argv[1] if len(sys.argv) > 1 else 1000)))
        
    # subscribe to pubnub-sensor-network channel and begin streaming
    pubnub.subscribe().channels('pubnub-market-orders').execute()

    # configure and start animation that calls function update
    stock_animation = animation.FuncAnimation(
        figure, update, frames=1000, repeat=False, interval=33)
    plt.tight_layout()
    plt.show()  # keeps graph on screen until you dismiss its window

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