bullish/backend/app/utils.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""Utils for bullish."""

# standard imports
import csv
import datetime
import logging

from io import BytesIO, TextIOWrapper
from zipfile import ZipFile

# third-party imports
import django_rq
import requests

from django_redis import get_redis_connection
from django.db import transaction

# app imports
from app.models import BhavCopyEquity


cache = get_redis_connection("default")
logger = logging.getLogger(__name__)


def fetch_bhav_copy_equity_data(date=None):
    """Fetch data from BSE India website."""
    # hack: since bseindia website doesn't respond well to python requests
    user_agent = 'Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Firefox/78.0'
    headers = {
        'User-Agent': user_agent
    }
    if date is None:
        date = datetime.datetime.now()
    datestr = date.strftime("%d%m%y")
    zipurl = f'https://www.bseindia.com/download/BhavCopy/Equity/EQ{datestr}_CSV.ZIP'
    logger.info('Fetching data from %s', zipurl)
    resp = requests.get(zipurl, headers=headers)

    if resp.ok:
        with ZipFile(BytesIO(resp.content)) as bhavcopy_zf:
            csv_file = bhavcopy_zf.namelist()[0]
            with bhavcopy_zf.open(csv_file, 'r') as infile:
                data = list(csv.reader(TextIOWrapper(infile, 'utf-8')))
        return data
    raise ValueError('Fetching data from BSE unsuccessful')


def populate_bhav_copy_data(date=None):
    """Populate DB with Bhav Copy data."""
    try:
        data = fetch_bhav_copy_equity_data(date=date)
    except Exception as err:
        # Potentially add code for alerting if needed
        # Repeat job after 10 mins if job fails
        scheduler = django_rq.get_scheduler('default')
        scheduler.schedule(
            scheduled_time=datetime.datetime.now()+datetime.timedelta(minutes=10),
            func=populate_bhav_copy_data,
        )
        raise ValueError(f"Error fetching data from BSE for {date}\nDetails: {err}")
    else:
        del data[0]  # delete title row
        populate_bhav_copy_data_into_redis(data, date=date)
        populate_bhav_copy_data_into_postgres(data, date=date)


def populate_bhav_copy_data_into_redis(data, date):
    logger.info('Populating data into redis')
    datestr = date.strftime("%d%m%y")
    pipe = cache.pipeline()
    stocks_key = f"stocks:{datestr}"
    cache.delete(stocks_key)
    data = stocks_csv_to_json(data)
    for stock in data:
        # prevent creation of duplicate entries
        stock_code = stock.get('sc_code')
        pipe.rpush(stocks_key, stock_code)
        pipe.hset(
            f"stock:{datestr}:{stock_code}",
            mapping=stock
        )
    pipe.execute()


@transaction.atomic
def populate_bhav_copy_data_into_postgres(data, date=None):
    logger.info('Populating data into postgres for %s', date)
    if date is None:
        date = datetime.datetime.now().date()
    for stock in data:
        BhavCopyEquity.objects.get_or_create(
            date=date,
            sc_code=int(stock[0]),
            sc_name=stock[1],
            sc_group=stock[2],
            sc_type=stock[3],
            open_price=float(stock[4]),
            high_price=float(stock[5]),
            low_price=float(stock[6]),
            close_price=float(stock[7]),
            last_price=float(stock[8]),
            prevclose_price=float(stock[9]),
            no_trades=int(stock[10]),
            no_of_shrs=int(stock[11]),
            net_turnov=float(stock[12]),
            tdcloindi=stock[13],
        )


def stocks_csv_to_json(data):
    stocks = []
    for stock in data:
        stocks.append({
            "sc_code": stock[0],
            "sc_name": stock[1],
            "sc_group": stock[2],
            "sc_type": stock[3],
            "open_price": float(stock[4]),
            "high_price": float(stock[5]),
            "low_price": float(stock[6]),
            "close_price": float(stock[7]),
            "last_price": float(stock[8]),
            "prevclose_price": float(stock[9]),
            "no_trades": int(stock[10]),
            "no_of_shrs": int(stock[11]),
            "net_turnov": float(stock[12]),
            "tdcloindi": stock[13],
        })
    return stocks


def verify_date(date, ret_message):
    # Verify Date
    logger.info('Verifying date %s', date)
    req_date = datetime.datetime.strptime(date, '%Y-%m-%d')
    # 18:00 IST == 12:30 UTC
    today = datetime.datetime.now().replace(hour=12, minute=30, second=0, microsecond=0)
    logger.info('Req Date: %s; Today: %s', req_date, today)
    if req_date > today:
        ret_message = "Time travel not yet invented! Returning latest available data."
        req_date = today
    if req_date.date() == today.date() and req_date < today:
        req_date = today - datetime.timedelta(days=1)
    return req_date, ret_message