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dupeguru/hscommon/currency.py
2013-06-22 21:32:23 -04:00

457 lines
22 KiB
Python

# Created By: Virgil Dupras
# Created On: 2008-04-20
# Copyright 2013 Hardcoded Software (http://www.hardcoded.net)
# This software is licensed under the "BSD" License as described in the "LICENSE" file,
# which should be included with this package. The terms are also available at
# http://www.hardcoded.net/licenses/bsd_license
from datetime import datetime, date, timedelta
import logging
import sqlite3 as sqlite
import threading
from queue import Queue, Empty
from . import io
from .path import Path
class Currency:
all = []
by_code = {}
by_name = {}
rates_db = None
def __new__(cls, code=None, name=None):
"""Returns the currency with the given code."""
assert (code is None and name is not None) or (code is not None and name is None)
if code is not None:
try:
return cls.by_code[code]
except KeyError:
raise ValueError('Unknown currency code: %r' % code)
else:
try:
return cls.by_name[name]
except KeyError:
raise ValueError('Unknown currency name: %r' % name)
def __getnewargs__(self):
return (self.code,)
def __getstate__(self):
return None
def __setstate__(self, state):
pass
def __repr__(self):
return '<Currency %s>' % self.code
@staticmethod
def register(code, name, exponent=2, start_date=None, start_rate=1, stop_date=None, latest_rate=1):
"""Registers a new currency and returns it."""
assert code not in Currency.by_code
assert name not in Currency.by_name
currency = object.__new__(Currency)
currency.code = code
currency.name = name
currency.exponent = exponent
currency.start_date = start_date
currency.start_rate = start_rate
currency.stop_date = stop_date
currency.latest_rate = latest_rate
Currency.by_code[code] = currency
Currency.by_name[name] = currency
Currency.all.append(currency)
return currency
@staticmethod
def set_rates_db(db):
Currency.rates_db = db
@staticmethod
def get_rates_db():
if Currency.rates_db is None:
Currency.rates_db = RatesDB() # Make sure we always have some db to work with
return Currency.rates_db
def rates_date_range(self):
"""Returns the range of date for which rates are available for this currency."""
return self.get_rates_db().date_range(self.code)
def value_in(self, currency, date):
"""Returns the value of this currency in terms of the other currency on the given date."""
if self.start_date is not None and date < self.start_date:
return self.start_rate
elif self.stop_date is not None and date > self.stop_date:
return self.latest_rate
else:
return self.get_rates_db().get_rate(date, self.code, currency.code)
def set_CAD_value(self, value, date):
"""Sets the currency's value in CAD on the given date."""
self.get_rates_db().set_CAD_value(date, self.code, value)
BUILTIN_CURRENCIES = {
# In order we want to list them
Currency.register('USD', 'U.S. dollar',
start_date=date(1998, 1, 2), start_rate=1.425, latest_rate=1.0128),
Currency.register('EUR', 'European Euro',
start_date=date(1999, 1, 4), start_rate=1.8123, latest_rate=1.3298),
Currency.register('GBP', 'U.K. pound sterling',
start_date=date(1998, 1, 2), start_rate=2.3397, latest_rate=1.5349),
Currency.register('CAD', 'Canadian dollar',
latest_rate=1),
Currency.register('AUD', 'Australian dollar',
start_date=date(1998, 1, 2), start_rate=0.9267, latest_rate=0.9336),
Currency.register('JPY', 'Japanese yen',
exponent=0, start_date=date(1998, 1, 2), start_rate=0.01076, latest_rate=0.01076),
Currency.register('INR', 'Indian rupee',
start_date=date(1998, 1, 2), start_rate=0.03627, latest_rate=0.02273),
Currency.register('NZD', 'New Zealand dollar',
start_date=date(1998, 1, 2), start_rate=0.8225, latest_rate=0.7257),
Currency.register('CHF', 'Swiss franc',
start_date=date(1998, 1, 2), start_rate=0.9717, latest_rate=0.9273),
Currency.register('ZAR', 'South African rand',
start_date=date(1998, 1, 2), start_rate=0.292, latest_rate=0.1353),
# The rest, alphabetical
Currency.register('AED', 'U.A.E. dirham',
start_date=date(2007, 9, 4), start_rate=0.2858, latest_rate=0.2757),
Currency.register('ANG', 'Neth. Antilles florin',
start_date=date(1998, 1, 2), start_rate=0.7961, latest_rate=0.5722),
Currency.register('ARS', 'Argentine peso',
start_date=date(1998, 1, 2), start_rate=1.4259, latest_rate=0.2589),
Currency.register('ATS', 'Austrian schilling',
start_date=date(1998, 1, 2), start_rate=0.1123, stop_date=date(2001, 12, 31), latest_rate=0.10309), # obsolete (euro)
Currency.register('BBD', 'Barbadian dollar',
start_date=date(2010, 4, 30), start_rate=0.5003, latest_rate=0.5003),
Currency.register('BEF', 'Belgian franc',
start_date=date(1998, 1, 2), start_rate=0.03832, stop_date=date(2001, 12, 31), latest_rate=0.03516), # obsolete (euro)
Currency.register('BHD', 'Bahraini dinar',
exponent=3, start_date=date(2008, 11, 8), start_rate=3.1518, latest_rate=2.6603),
Currency.register('BRL', 'Brazilian real',
start_date=date(1998, 1, 2), start_rate=1.2707, latest_rate=0.5741),
Currency.register('BSD', 'Bahamian dollar',
start_date=date(1998, 1, 2), start_rate=1.425, latest_rate=1.0128),
Currency.register('CLP', 'Chilean peso',
exponent=0, start_date=date(1998, 1, 2), start_rate=0.003236, latest_rate=0.001923),
Currency.register('CNY', 'Chinese renminbi',
start_date=date(1998, 1, 2), start_rate=0.1721, latest_rate=0.1484),
Currency.register('COP', 'Colombian peso',
start_date=date(1998, 1, 2), start_rate=0.00109, latest_rate=0.000513),
Currency.register('CZK', 'Czech Republic koruna',
start_date=date(1998, 2, 2), start_rate=0.04154, latest_rate=0.05202),
Currency.register('DEM', 'German deutsche mark',
start_date=date(1998, 1, 2), start_rate=0.7904, stop_date=date(2001, 12, 31), latest_rate=0.7253), # obsolete (euro)
Currency.register('DKK', 'Danish krone',
start_date=date(1998, 1, 2), start_rate=0.2075, latest_rate=0.1785),
Currency.register('EGP', 'Egyptian Pound',
start_date=date(2008, 11, 27), start_rate=0.2232, latest_rate=0.1805),
Currency.register('ESP', 'Spanish peseta',
exponent=0, start_date=date(1998, 1, 2), start_rate=0.009334, stop_date=date(2001, 12, 31), latest_rate=0.008526), # obsolete (euro)
Currency.register('FIM', 'Finnish markka',
start_date=date(1998, 1, 2), start_rate=0.2611, stop_date=date(2001, 12, 31), latest_rate=0.2386), # obsolete (euro)
Currency.register('FJD', 'Fiji dollar',
start_date=date(1998, 1, 2), start_rate=0.9198, latest_rate=0.5235),
Currency.register('FRF', 'French franc',
start_date=date(1998, 1, 2), start_rate=0.2362, stop_date=date(2001, 12, 31), latest_rate=0.2163), # obsolete (euro)
Currency.register('GHC', 'Ghanaian cedi (old)',
start_date=date(1998, 1, 2), start_rate=0.00063, stop_date=date(2007, 6, 29), latest_rate=0.000115), # obsolete
Currency.register('GHS', 'Ghanaian cedi',
start_date=date(2007, 7, 3), start_rate=1.1397, latest_rate=0.7134),
Currency.register('GRD', 'Greek drachma',
start_date=date(1998, 1, 2), start_rate=0.005, stop_date=date(2001, 12, 31), latest_rate=0.004163), # obsolete (euro)
Currency.register('GTQ', 'Guatemalan quetzal',
start_date=date(2004, 12, 21), start_rate=0.15762, latest_rate=0.1264),
Currency.register('HKD', 'Hong Kong dollar',
start_date=date(1998, 1, 2), start_rate=0.1838, latest_rate=0.130385),
Currency.register('HNL', 'Honduran lempira',
start_date=date(1998, 1, 2), start_rate=0.108, latest_rate=0.0536),
Currency.register('HRK', 'Croatian kuna',
start_date=date(2002, 3, 1), start_rate=0.1863, latest_rate=0.1837),
Currency.register('HUF', 'Hungarian forint',
start_date=date(1998, 2, 2), start_rate=0.007003, latest_rate=0.00493),
Currency.register('IDR', 'Indonesian rupiah',
start_date=date(1998, 2, 2), start_rate=0.000145, latest_rate=0.000112),
Currency.register('IEP', 'Irish pound',
start_date=date(1998, 1, 2), start_rate=2.0235, stop_date=date(2001, 12, 31), latest_rate=1.8012), # obsolete (euro)
Currency.register('ILS', 'Israeli new shekel',
start_date=date(1998, 1, 2), start_rate=0.4021, latest_rate=0.2706),
Currency.register('ISK', 'Icelandic krona',
exponent=0, start_date=date(1998, 1, 2), start_rate=0.01962, latest_rate=0.00782),
Currency.register('ITL', 'Italian lira',
exponent=0, start_date=date(1998, 1, 2), start_rate=0.000804, stop_date=date(2001, 12, 31), latest_rate=0.000733), # obsolete (euro)
Currency.register('JMD', 'Jamaican dollar',
start_date=date(2001, 6, 25), start_rate=0.03341, latest_rate=0.01145),
Currency.register('KRW', 'South Korean won',
exponent=0, start_date=date(1998, 1, 2), start_rate=0.000841, latest_rate=0.000905),
Currency.register('LKR', 'Sri Lanka rupee',
start_date=date(1998, 1, 2), start_rate=0.02304, latest_rate=0.0089),
Currency.register('LTL', 'Lithuanian litas',
start_date=date(2010, 4, 29), start_rate=0.384, latest_rate=0.384),
Currency.register('LVL', 'Latvian lats',
start_date=date(2011, 2, 6), start_rate=1.9136, latest_rate=1.9136),
Currency.register('MAD', 'Moroccan dirham',
start_date=date(1998, 1, 2), start_rate=0.1461, latest_rate=0.1195),
Currency.register('MMK', 'Myanmar (Burma) kyat',
start_date=date(1998, 1, 2), start_rate=0.226, latest_rate=0.1793),
Currency.register('MXN', 'Mexican peso',
start_date=date(1998, 1, 2), start_rate=0.1769, latest_rate=0.08156),
Currency.register('MYR', 'Malaysian ringgit',
start_date=date(1998, 1, 2), start_rate=0.3594, latest_rate=0.3149),
# MZN in not supported in any of my sources, so I'm just creating it with a fixed rate.
Currency.register('MZN', 'Mozambican metical',
start_date=date(2011, 2, 6), start_rate=0.03, stop_date=date(2011, 2, 5), latest_rate=0.03),
Currency.register('NIO', 'Nicaraguan córdoba',
start_date=date(2011, 10, 12), start_rate=0.0448, latest_rate=0.0448),
Currency.register('NLG', 'Netherlands guilder',
start_date=date(1998, 1, 2), start_rate=0.7013, stop_date=date(2001, 12, 31), latest_rate=0.6437), # obsolete (euro)
Currency.register('NOK', 'Norwegian krone',
start_date=date(1998, 1, 2), start_rate=0.1934, latest_rate=0.1689),
Currency.register('PAB', 'Panamanian balboa',
start_date=date(1998, 1, 2), start_rate=1.425, latest_rate=1.0128),
Currency.register('PEN', 'Peruvian new sol',
start_date=date(1998, 1, 2), start_rate=0.5234, latest_rate=0.3558),
Currency.register('PHP', 'Philippine peso',
start_date=date(1998, 1, 2), start_rate=0.0345, latest_rate=0.02262),
Currency.register('PKR', 'Pakistan rupee',
start_date=date(1998, 1, 2), start_rate=0.03238, latest_rate=0.01206),
Currency.register('PLN', 'Polish zloty',
start_date=date(1998, 2, 2), start_rate=0.4108, latest_rate=0.3382),
Currency.register('PTE', 'Portuguese escudo',
exponent=0, start_date=date(1998, 1, 2), start_rate=0.007726, stop_date=date(2001, 12, 31), latest_rate=0.007076), # obsolete (euro)
Currency.register('RON', 'Romanian new leu',
start_date=date(2007, 9, 4), start_rate=0.4314, latest_rate=0.3215),
Currency.register('RSD', 'Serbian dinar',
start_date=date(2007, 9, 4), start_rate=0.0179, latest_rate=0.01338),
Currency.register('RUB', 'Russian rouble',
start_date=date(1998, 1, 2), start_rate=0.2375, latest_rate=0.03443),
Currency.register('SAR', 'Saudi riyal',
start_date=date(2012, 9, 13), start_rate=0.26, latest_rate=0.26),
Currency.register('SEK', 'Swedish krona',
start_date=date(1998, 1, 2), start_rate=0.1787, latest_rate=0.1378),
Currency.register('SGD', 'Singapore dollar',
start_date=date(1998, 1, 2), start_rate=0.84, latest_rate=0.7358),
Currency.register('SIT', 'Slovenian tolar',
start_date=date(2002, 3, 1), start_rate=0.006174, stop_date=date(2006, 12, 29), latest_rate=0.006419), # obsolete (euro)
Currency.register('SKK', 'Slovak koruna',
start_date=date(2002, 3, 1), start_rate=0.03308, stop_date=date(2008, 12, 31), latest_rate=0.05661), # obsolete (euro)
Currency.register('THB', 'Thai baht',
start_date=date(1998, 1, 2), start_rate=0.0296, latest_rate=0.03134),
Currency.register('TND', 'Tunisian dinar',
exponent=3, start_date=date(1998, 1, 2), start_rate=1.2372, latest_rate=0.7037),
Currency.register('TRL', 'Turkish lira',
exponent=0, start_date=date(1998, 1, 2), start_rate=7.0e-06, stop_date=date(2004, 12, 31), latest_rate=8.925e-07), # obsolete
Currency.register('TWD', 'Taiwanese new dollar',
start_date=date(1998, 1, 2), start_rate=0.04338, latest_rate=0.03218),
Currency.register('UAH', 'Ukrainian hryvnia',
start_date=date(2010, 4, 29), start_rate=0.1266, latest_rate=0.1266),
Currency.register('VEB', 'Venezuelan bolivar',
exponent=0, start_date=date(1998, 1, 2), start_rate=0.002827, stop_date=date(2007, 12, 31), latest_rate=0.00046), # obsolete
Currency.register('VEF', 'Venezuelan bolivar fuerte',
start_date=date(2008, 1, 2), start_rate=0.4623, latest_rate=0.2358),
Currency.register('VND', 'Vietnamese dong',
start_date=date(2004, 1, 1), start_rate=8.2e-05, latest_rate=5.3e-05),
Currency.register('XAF', 'CFA franc',
exponent=0, start_date=date(1998, 1, 2), start_rate=0.002362, latest_rate=0.002027),
Currency.register('XCD', 'East Caribbean dollar',
start_date=date(1998, 1, 2), start_rate=0.5278, latest_rate=0.3793),
Currency.register('XPF', 'CFP franc',
exponent=0, start_date=date(1998, 1, 2), start_rate=0.01299, latest_rate=0.01114),
}
BUILTIN_CURRENCY_CODES = {c.code for c in BUILTIN_CURRENCIES}
# For legacy purpose, we need to maintain these global variables
CAD = Currency(code='CAD')
USD = Currency(code='USD')
EUR = Currency(code='EUR')
class CurrencyNotSupportedException(Exception):
"""The current exchange rate provider doesn't support the requested currency."""
class RatesDB:
"""Stores exchange rates for currencies.
The currencies are identified with ISO 4217 code (USD, CAD, EUR, etc.).
The rates are represented as float and represent the value of the currency in CAD.
"""
def __init__(self, db_or_path=':memory:', async=True):
self._cache = {} # {(date, currency): CAD value
self.db_or_path = db_or_path
if isinstance(db_or_path, (str, Path)):
self.con = sqlite.connect(str(db_or_path))
else:
self.con = db_or_path
self._execute("select * from rates where 1=2")
self._rate_providers = []
self.async = async
self._fetched_values = Queue()
self._fetched_ranges = {} # a currency --> (start, end) map
def _execute(self, *args, **kwargs):
def create_tables():
# date is stored as a TEXT YYYYMMDD
sql = "create table rates(date TEXT, currency TEXT, rate REAL NOT NULL)"
self.con.execute(sql)
sql = "create unique index idx_rate on rates (date, currency)"
self.con.execute(sql)
try:
return self.con.execute(*args, **kwargs)
except sqlite.OperationalError: # new db, or other problems
try:
create_tables()
except Exception:
logging.warning("Messy problems with the currency db, starting anew with a memory db")
self.con = sqlite.connect(':memory:')
create_tables()
except sqlite.DatabaseError: # corrupt db
logging.warning("Corrupt currency database at {0}. Starting over.".format(repr(self.db_or_path)))
if isinstance(self.db_or_path, (str, Path)):
self.con.close()
io.remove(Path(self.db_or_path))
self.con = sqlite.connect(str(self.db_or_path))
else:
logging.warning("Can't re-use the file, using a memory table")
self.con = sqlite.connect(':memory:')
create_tables()
return self.con.execute(*args, **kwargs) # try again
def _seek_value_in_CAD(self, str_date, currency_code):
if currency_code == 'CAD':
return 1
def seek(date_op, desc):
sql = "select rate from rates where date %s ? and currency = ? order by date %s limit 1" % (date_op, desc)
cur = self._execute(sql, [str_date, currency_code])
row = cur.fetchone()
if row:
return row[0]
return seek('<=', 'desc') or seek('>=', '') or Currency(currency_code).latest_rate
def _save_fetched_rates(self):
while True:
try:
rates, currency = self._fetched_values.get_nowait()
for rate_date, rate in rates:
self.set_CAD_value(rate_date, currency, rate)
except Empty:
break
def clear_cache(self):
self._cache = {}
def date_range(self, currency_code):
"""Returns (start, end) of the cached rates for currency"""
sql = "select min(date), max(date) from rates where currency = '%s'" % currency_code
cur = self._execute(sql)
start, end = cur.fetchone()
if start and end:
convert = lambda s: datetime.strptime(s, '%Y%m%d').date()
return convert(start), convert(end)
else:
return None
def get_rate(self, date, currency1_code, currency2_code):
"""Returns the exchange rate between currency1 and currency2 for date.
The rate returned means '1 unit of currency1 is worth X units of currency2'.
The rate of the nearest date that is smaller than 'date' is returned. If
there is none, a seek for a rate with a higher date will be made.
"""
# We want to check self._fetched_values for rates to add.
if not self._fetched_values.empty():
self._save_fetched_rates()
# This method is a bottleneck and has been optimized for speed.
value1 = None
value2 = None
if currency1_code == 'CAD':
value1 = 1
else:
value1 = self._cache.get((date, currency1_code))
if currency2_code == 'CAD':
value2 = 1
else:
value2 = self._cache.get((date, currency2_code))
if value1 is None or value2 is None:
str_date = '%d%02d%02d' % (date.year, date.month, date.day)
if value1 is None:
value1 = self._seek_value_in_CAD(str_date, currency1_code)
self._cache[(date, currency1_code)] = value1
if value2 is None:
value2 = self._seek_value_in_CAD(str_date, currency2_code)
self._cache[(date, currency2_code)] = value2
return value1 / value2
def set_CAD_value(self, date, currency_code, value):
"""Sets the daily value in CAD for currency at date"""
# we must clear the whole cache because there might be other dates affected by this change
# (dates when the currency server has no rates).
self.clear_cache()
str_date = '%d%02d%02d' % (date.year, date.month, date.day)
sql = "replace into rates(date, currency, rate) values(?, ?, ?)"
self._execute(sql, [str_date, currency_code, value])
self.con.commit()
def register_rate_provider(self, rate_provider):
"""Adds `rate_provider` to the list of providers supported by this DB.
A provider if a function(currency, start_date, end_date) that returns a list of
(rate_date, float_rate) as a result. This function will be called asyncronously, so it's ok
if it takes a long time to return.
The rates returned must be the value of 1 `currency` in CAD (Canadian Dollars) at the
specified date.
The provider can be asked for any currency. If it doesn't support it, it has to raise
CurrencyNotSupportedException.
If we support the currency but that there is no rate available for the specified range,
simply return an empty list or None.
"""
self._rate_providers.append(rate_provider)
def ensure_rates(self, start_date, currencies):
"""Ensures that the DB has all the rates it needs for 'currencies' between 'start_date' and today
If there is any rate missing, a request will be made to the currency server. The requests
are made asynchronously.
"""
def do():
for currency, fetch_start, fetch_end in currencies_and_range:
for rate_provider in self._rate_providers:
try:
values = rate_provider(currency, fetch_start, fetch_end)
except CurrencyNotSupportedException:
continue
else:
if values:
self._fetched_values.put((values, currency))
currencies_and_range = []
for currency in currencies:
if currency == 'CAD':
continue
try:
cached_range = self._fetched_ranges[currency]
except KeyError:
cached_range = self.date_range(currency)
range_start = start_date
range_end = date.today()
if cached_range is not None:
cached_start, cached_end = cached_range
if range_start >= cached_start:
# Make a forward fetch
range_start = cached_end + timedelta(days=1)
else:
# Make a backward fetch
range_end = cached_start - timedelta(days=1)
if range_start <= range_end:
currencies_and_range.append((currency, range_start, range_end))
self._fetched_ranges[currency] = (start_date, date.today())
if self.async:
threading.Thread(target=do).start()
else:
do()