oxrlib/oxrlib/config.py
Brett Smith 55f5833aa0 historical: Add a setting to denominate Ledger conversions.
This makes conversion output easier to add to ledgers directly.
2017-06-09 11:06:51 -04:00

228 lines
8.8 KiB
Python

import argparse
import configparser
import datetime
import decimal
import os.path
import pathlib
from . import cache, loaders
HOME_PATH = pathlib.Path(os.path.expanduser('~'))
def currency_code(s):
if not ((len(s) == 3) and s.isalpha()):
raise ValueError("bad currency code: {!r}".format(s))
return s.upper()
def currency_list(s):
return [currency_code(code.strip()) for code in s.split(',')]
class Configuration:
DATE_SEPS = frozenset('.-/ ')
DEFAULT_CONFIG_PATH = pathlib.Path(HOME_PATH, '.config', 'oxrlib.ini')
NO_DENOMINATION = object()
PREPOSITIONS = frozenset(['in', 'to', 'into'])
TODAY = datetime.date.today()
def __init__(self, arglist):
argparser = self._build_argparser()
self.error = argparser.error
self.args = argparser.parse_args(arglist)
if self.args.config_file is None:
self.args.config_file = [self.DEFAULT_CONFIG_PATH]
self.conffile = self._build_conffile()
conffile_paths = [path.as_posix() for path in self.args.config_file]
read_files = self.conffile.read(conffile_paths)
for expected_path, read_path in zip(conffile_paths, read_files):
if read_path != expected_path:
self.error("failed to read configuration file {!r}".format(expected_path))
if not hasattr(self.args, 'command'):
argparser.print_help()
exit(2)
try:
post_hook = getattr(self, '_post_hook_' + self.args.command)
except AttributeError:
pass
else:
post_hook()
def _date_from_s(self, s):
clean_s = s.strip()
numbers = []
seen_seps = set()
start_index = 0
for index, c in (pair for pair in enumerate(clean_s) if pair[1] in self.DATE_SEPS):
seen_seps.add(c)
numbers.append(int(clean_s[start_index:index], 10))
start_index = index + 1
numbers.append(int(clean_s[start_index:], 10))
if (len(numbers) > 3) or (len(seen_seps) > 1):
raise ValueError("can't parse date from {!r}".format(s))
replacements = dict(zip(['day', 'month', 'year'], reversed(numbers)))
return self.TODAY.replace(**replacements)
def _build_argparser(self):
prog_parser = argparse.ArgumentParser()
prog_parser.add_argument(
'--config-file', '-c',
action='append', type=pathlib.Path,
help="Path of a configuration file to read",
)
subparsers = prog_parser.add_subparsers()
hist_parser = subparsers.add_parser(
'historical', aliases=['hist'],
usage='%(prog)s [[YYYY-]MM-]DD [[amount] code] [[in] code]',
help="Show a currency conversion or rate from a past date",
)
hist_parser.set_defaults(
command='historical',
amount=None,
from_currency=None,
ledger=None,
)
hist_parser.add_argument(
'--base',
metavar='CODE', type=currency_code,
help="Base currency (default USD)",
)
hist_parser.add_argument(
'--ledger', '-L',
action='store_true',
help="Output the rate or conversion in Ledger format",
)
hist_parser.add_argument(
'--no-ledger',
action='store_false', dest='ledger',
help="Turn off an earlier --ledger setting",
)
hist_parser.add_argument(
'--denomination',
metavar='CODE', type=currency_code,
help="In Ledger conversion output, always show rates to convert "
"to this currency",
)
hist_parser.add_argument(
'--no-denomination',
dest='denomination', action='store_const', const=self.NO_DENOMINATION,
help="Turn off an earlier --denomination setting",
)
hist_parser.add_argument(
'--signed-currency', '--sign-currency',
type=currency_code, action='append', dest='signed_currencies',
metavar='CODE',
help="In Ledger output, use a sign for this currency if known. "
"Can be specified multiple times.",
)
hist_parser.add_argument(
'date',
type=self._date_from_s,
help="Use rates from this date, in YYYY-MM-DD format. "
"If you omit the year or month, it fills in the current year/month."
)
hist_parser.add_argument(
'word1', nargs='?', metavar='first code',
help="Convert or show rates from this currency, in three-letter code format. "
"If not specified, show all rates on the given date.",
)
hist_parser.add_argument(
'word2', nargs='?', metavar='amount',
help="Convert this amount of currency. If not specified, show rates.",
)
hist_parser.add_argument(
'word3', nargs='?', metavar='second code',
help="Convert to this currency, in three-letter code format. "
"If not specified, defaults to the base currency.",
)
hist_parser.add_argument('word4', nargs='?', help=argparse.SUPPRESS)
return prog_parser
def _build_conffile(self):
return configparser.ConfigParser()
def _read_from_conffile(self, argname, sectionname, fallback, convert_to=None,
confname=None, getter='get', unset=None,
*, convert_fallback=False):
if getattr(self.args, argname) is not unset:
return
elif confname is None:
confname = argname
get_method = getattr(self.conffile, getter)
value = get_method(sectionname, confname, fallback=fallback)
if (convert_to is not None
and (value is not fallback or convert_fallback)):
value = self._convert_or_error(convert_to, value, confname)
setattr(self.args, argname, value)
def _convert_or_error(self, argtype, s_value, argname=None, typename=None):
try:
return argtype(s_value)
except (decimal.InvalidOperation, TypeError, ValueError):
errmsg = []
if argname:
errmsg.append("argument {}".format(argname))
if typename is None:
typename = argtype.__name__.replace('_', ' ')
errmsg.append("invalid {} value".format(typename))
errmsg.append(repr(s_value))
self.error(': '.join(errmsg))
def _post_hook_historical(self):
year = self.args.date.year
if year < 100:
# Don't let the user specify ambiguous dates.
self.error("historical data not available from year {}".format(year))
self._read_from_conffile('base', 'Historical', 'USD', currency_code)
if self.args.denomination is self.NO_DENOMINATION:
self.args.denomination = None
else:
self._read_from_conffile('denomination', 'Historical', None, currency_code)
self._read_from_conffile('signed_currencies', 'Historical', self.args.base,
currency_list, convert_fallback=True)
self._read_from_conffile('ledger', 'Historical', False, getter='getboolean')
self.args.to_currency = self.args.base
if self.args.word4 and (self.args.word3.lower() in self.PREPOSITIONS):
self.args.word3 = self.args.word4
if self.args.word1 is None:
pass
elif self.args.word2 is None:
self.args.from_currency = self._convert_or_error(
currency_code, self.args.word1)
else:
self.args.amount = self._convert_or_error(
decimal.Decimal, self.args.word1)
self.args.from_currency = self._convert_or_error(
currency_code, self.args.word2)
if self.args.word3 is not None:
self.args.to_currency = self._convert_or_error(
currency_code, self.args.word3 or self.args.base)
def _build_cache_loader(self):
kwargs = dict(self.conffile.items('Cache'))
try:
kwargs['dir_path'] = pathlib.Path(kwargs.pop('directory'))
except KeyError:
pass
self.cache = cache.CacheWriter(**kwargs)
return loaders.FileCache(**kwargs)
def _build_oxrapi_loader(self):
kwargs = dict(self.conffile.items('OXR'))
return loaders.OXRAPIRequest(**kwargs)
def get_loaders(self):
loader_chain = loaders.LoaderChain()
for build_func in [
self._build_cache_loader,
self._build_oxrapi_loader,
]:
try:
loader = build_func()
except (TypeError, ValueError, configparser.NoSectionError):
pass
else:
loader_chain.add_loader(loader)
return loader_chain