app.py

from gevent import monkey
monkey.patch_all()

import os
import pdb
import cgi
import uuid
import redis
from dotenv import load_dotenv
from flask_socketio import SocketIO
from flask import Flask, render_template

load_dotenv()
app = Flask(__name__)
socketio = SocketIO(app)
db = redis.Redis()

YES_VOTE_COUNT_KEY = 'yes_vote_count'
NAMESPACE = '/websocket'
CURRENT_CANDIDATE_KEY = 'current_candidate'
NO_VOTE_COUNT_KEY = 'no_vote_count'
USERS_VOTED_KEY = 'users_voted'

# Helpers
def emit_votes(yes_count, no_count):
    if yes_count is None or no_count is None:
        return
    yes_count_str = str(yes_count) if type(yes_count) == int else yes_count.decode('utf-8')
    no_count_str = str(no_count) if type(no_count) == int else no_count.decode('utf-8') 
    socketio.emit('vote',
            {YES_VOTE_COUNT_KEY: yes_count_str,
                NO_VOTE_COUNT_KEY: no_count_str
                },
            namespace=NAMESPACE)

# HTTP routes
@app.route('/')
def index():
    return render_template('index.html')

@app.route('/admin')
def admin():
    return render_template('admin.html')

# WebSocket routes
@socketio.on('connect', namespace=NAMESPACE)
def ws_connect():
    emit_votes(db.get(YES_VOTE_COUNT_KEY), db.get(NO_VOTE_COUNT_KEY))
    unique_id = str(uuid.uuid4())
    socketio.emit('uuid', {'uuid': unique_id}, namespace=NAMESPACE)
    try: # I don't care if there is no current candidate, just move on
        socketio.emit('candidate', {'candidate': db.get(CURRENT_CANDIDATE_KEY).decode('utf-8')}, namespace=NAMESPACE)
    except AttributeError:
        pass

@socketio.on('msg', namespace=NAMESPACE)
def ws_chat(msg):
    socketio.emit('msg', {'msg': cgi.escape(msg['msg'])}, namespace=NAMESPACE)

@socketio.on('candidate', namespace=NAMESPACE)
def ws_candidate(msg):
    db.set(CURRENT_CANDIDATE_KEY, msg['candidate'])
    socketio.emit('candidate', {'candidate': cgi.escape(msg['candidate'])}, namespace=NAMESPACE)

@socketio.on('vote', namespace=NAMESPACE)
def ws_vote(msg):
    if not db.hexists(USERS_VOTED_KEY, msg['uuid']):
        if msg['vote'] == 'Yes':
            emit_votes(db.incr(YES_VOTE_COUNT_KEY), db.get(NO_VOTE_COUNT_KEY))
        elif msg['vote'] == 'No':
            emit_votes(db.get(YES_VOTE_COUNT_KEY), db.incr(NO_VOTE_COUNT_KEY))
        db.hset(USERS_VOTED_KEY, msg['uuid'], msg['vote'])
    else:
        vote = db.hget(USERS_VOTED_KEY, msg['uuid']).decode('utf-8')
        if vote != msg['vote']:
            if vote == 'Yes' and msg['vote'] == 'No':
                emit_votes(db.decr(YES_VOTE_COUNT_KEY), db.incr(NO_VOTE_COUNT_KEY))
            if vote == 'No' and msg['vote'] == 'Yes':
                emit_votes(db.incr(YES_VOTE_COUNT_KEY), db.decr(NO_VOTE_COUNT_KEY))
            db.hset(USERS_VOTED_KEY, msg['uuid'], msg['vote'])
    return 0

@socketio.on('vote_reset', namespace=NAMESPACE)
def ws_vote_reset(msg):
    db.set(YES_VOTE_COUNT_KEY, 0)
    db.set(NO_VOTE_COUNT_KEY, 0)
    db.delete(USERS_VOTED_KEY)
    emit_votes(db.get(YES_VOTE_COUNT_KEY), db.get(NO_VOTE_COUNT_KEY))
    socketio.emit('reset', {'none': None}, namespace=NAMESPACE)

if __name__=="__main__":
    socketio.run(app, host="0.0.0.0", debug=True)