Files
2017-12-08 20:39:54 +00:00

129 lines
3.1 KiB
Python

import pandas
import requests
import crayons
from pyquery import PyQuery as pq
import time
from collections import OrderedDict
from decimal import Decimal
url = 'https://coinmarketcap.com/currencies/views/all/'
session = requests.Session()
class MWT(object):
"""Memoize With Timeout"""
_caches = {}
_timeouts = {}
def __init__(self, timeout=2):
self.timeout = timeout
def collect(self):
"""Clear cache of results which have timed out"""
for func in self._caches:
cache = {}
for key in self._caches[func]:
if (time.time() - self._caches[func][key][1]) < self._timeouts[func]:
cache[key] = self._caches[func][key]
self._caches[func] = cache
def __call__(self, f):
self.cache = self._caches[f] = {}
self._timeouts[f] = self.timeout
def func(*args, **kwargs):
kw = sorted(kwargs.items())
key = (args, tuple(kw))
try:
v = self.cache[key]
if (time.time() - v[1]) > self.timeout:
raise KeyError
except KeyError:
v = self.cache[key] = f(*args, **kwargs), time.time()
return v[0]
func.func_name = f.__name__
return func
def convert_to_decimal(f):
return Decimal("{0:.8f}".format(f))
class Coin():
"""A Coin, unlike Mario's."""
def __init__(self, ticker):
self.ticker = ticker
self.name = None
self.rank = None
self._value = None
self.update()
def update(self):
coins = get_coins()
print(f'Fetching data on {crayons.cyan(self.ticker)}...')
self.name = coins[self.ticker]['name']
self.rank = coins[self.ticker]['rank']
self._usd = coins[self.ticker]['usd']
@property
def usd(self):
return self._usd
@property
def btc(self):
coins = get_coins()
rate = coins['btc']['usd']
return convert_to_decimal(self.usd / rate)
def value(self, coin):
"""Example: BTC -> ETH"""
return convert_to_decimal(self.btc / Coin(coin).btc)
def __repr__(self):
return f'<Coin ticker={self.ticker!r}>'
@MWT(timeout=300)
def get_coins():
coins_db = OrderedDict()
print(crayons.yellow('Scraping CoinMaketCap...'))
r = session.get(url)
html = pq(pq(r.content)('table')[0]).html()
df = pandas.read_html("<table>{}</table>".format(html))
df = pandas.concat(df)
btc_value = float(df.to_dict()['Price'][0][1:].replace(',', ''))
for row in df.itertuples():
rank = int(row[1])
name = ' '.join(row[2].split()[1:])
ticker = row[3].lower()
try:
usd = float(row[5][1:].replace(',', ''))
except ValueError:
usd = 0
finally:
pass
btc = convert_to_decimal(usd / btc_value)
coins_db.update({ticker: {'rank': rank, 'name': name, 'ticker': ticker, 'usd': usd, 'btc': btc}})
return coins_db
def get_coin(ticker):
return Coin(ticker)
if __name__ == '__main__':
print(get_coins())