217 lines
8.2 KiB
Python
217 lines
8.2 KiB
Python
# w.c.s. - web application for online forms
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# Copyright (C) 2005-2013 Entr'ouvert
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, see <http://www.gnu.org/licenses/>.
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import base64
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import datetime
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import hashlib
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import hmac
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import random
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import urllib.parse
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from django.utils.encoding import force_bytes, force_str
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from quixote import get_publisher, get_request
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from .api_access import ApiAccess
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from .qommon.errors import AccessForbiddenError, HttpResponse401Error, UnknownNameIdAccessForbiddenError
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from .qommon.misc import simplify
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DEFAULT_DURATION = 30
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def is_url_signed(utcnow=None, duration=DEFAULT_DURATION):
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if get_request().signed:
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return True
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query_string = get_request().get_query()
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if not query_string:
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return False
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signature = get_request().form.get('signature')
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if not isinstance(signature, str):
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return False
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signature = force_bytes(signature)
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# verify signature
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orig = get_request().form.get('orig')
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if not isinstance(orig, str):
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raise AccessForbiddenError('missing/multiple orig field')
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key = ApiAccess.get_access_key(orig) or get_publisher().get_site_option(orig, 'api-secrets')
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if not key:
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raise AccessForbiddenError('invalid orig')
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algo = get_request().form.get('algo')
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if not isinstance(algo, str):
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raise AccessForbiddenError('missing/multiple algo field')
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if algo not in hashlib.algorithms_guaranteed:
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raise AccessForbiddenError('invalid algo')
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try:
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algo = getattr(hashlib, algo)
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except AttributeError:
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raise AccessForbiddenError('invalid algo')
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if signature != base64.standard_b64encode(
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hmac.new(
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force_bytes(key), force_bytes(query_string[: query_string.find('&signature=')]), algo
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).digest()
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):
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raise AccessForbiddenError('invalid signature')
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timestamp = get_request().form.get('timestamp')
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if not isinstance(timestamp, str):
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raise AccessForbiddenError('missing/multiple timestamp field')
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try:
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timestamp = datetime.datetime.strptime(timestamp, '%Y-%m-%dT%H:%M:%SZ')
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except ValueError as e:
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raise AccessForbiddenError('invalid timestamp field; %s' % e)
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delta = (utcnow or datetime.datetime.utcnow()).replace(tzinfo=None) - timestamp
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if abs(delta) > datetime.timedelta(seconds=duration):
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period = 'past'
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if delta.total_seconds() < 0:
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delta = abs(delta)
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period = 'future'
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raise AccessForbiddenError(f'timestamp is more than {duration} seconds in the {period}: {delta}')
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# check nonce
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nonce = get_request().form.get('nonce')
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if nonce:
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# normalize nonce
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nonce = simplify(nonce[:128]).replace('/', '-')
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dummy, created = get_publisher().token_class.get_or_create(
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type='nonce', id=nonce, expiration_delay=duration
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)
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if not created:
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raise AccessForbiddenError('nonce already used')
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get_request().signed = True
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return True
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def check_http_basic_auth(api_name):
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auth_header = get_request().get_header('Authorization', '')
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if not auth_header.startswith('Basic '):
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# we do not handle other authentication schemes
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raise HttpResponse401Error(api_name, 'unhandled authorization header')
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auth_header = auth_header.split(' ', 1)[1]
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try:
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username, password = force_str(base64.decodebytes(force_bytes(auth_header))).split(':', 1)
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except ValueError: # invalid base64 or not enough values to unpack
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raise HttpResponse401Error(api_name, 'invalid authorization header')
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configured_password = get_publisher().get_site_option(username, section='api-http-auth-%s' % api_name)
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if configured_password != password:
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raise HttpResponse401Error(api_name, 'invalid authorization')
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def get_user_from_api_query_string(api_name=None):
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# check signature or auth header
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if not is_url_signed():
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user = getattr(get_request(), 'user', None)
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if user and user.is_api_user:
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return user
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if api_name:
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check_http_basic_auth(api_name)
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else:
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return None
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# check access restriction defined in API access object
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orig = get_request().form.get('orig')
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if orig:
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api_access = ApiAccess.get_by_identifier(orig)
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if api_access and api_access.get_roles():
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return api_access.get_as_api_user()
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# get user reference from query string
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user = None
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if get_request().form.get('email'):
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email = get_request().form.get('email')
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if not isinstance(email, str):
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raise AccessForbiddenError('multiple email field')
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users = list(get_publisher().user_class.get_users_with_email(email))
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if users:
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user = users[0]
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else:
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raise AccessForbiddenError('unknown email')
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elif get_request().form.get('NameID'):
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ni = get_request().form.get('NameID')
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if not isinstance(ni, str):
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raise AccessForbiddenError('multiple NameID field')
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users = list(get_publisher().user_class.get_users_with_name_identifier(ni))
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if users:
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user = users[0]
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else:
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raise UnknownNameIdAccessForbiddenError('unknown NameID')
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elif 'email' in get_request().form or 'NameID' in get_request().form:
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# email or NameID were given as empty to the query string, this maps
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# the anonymous user case.
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return False
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return user
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def sign_url(url, key, algo='sha256', timestamp=None, nonce=None):
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parsed = urllib.parse.urlparse(url)
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new_query = sign_query(parsed.query, key, algo, timestamp, nonce)
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return urllib.parse.urlunparse(parsed[:4] + (new_query,) + parsed[5:])
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def sign_query(query, key, algo='sha256', timestamp=None, nonce=None):
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if timestamp is None:
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timestamp = datetime.datetime.utcnow()
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timestamp = timestamp.strftime('%Y-%m-%dT%H:%M:%SZ')
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if nonce is None:
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# rstrip('L') for py2/3 compatibility, as py2 formats number as 0x...L, and py3 as 0x...
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nonce = hex(random.getrandbits(128))[2:].rstrip('L')
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new_query = query
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if new_query:
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new_query += '&'
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new_query += urllib.parse.urlencode((('algo', algo), ('timestamp', timestamp), ('nonce', nonce)))
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signature = base64.b64encode(sign_string(new_query, key, algo=algo))
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new_query += '&signature=' + urllib.parse.quote(signature)
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return new_query
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def sign_string(s, key, algo='sha256', timedelta=30):
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digestmod = getattr(hashlib, algo)
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hash = hmac.HMAC(force_bytes(key), digestmod=digestmod, msg=force_bytes(s))
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return hash.digest()
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class MissingSecret(Exception):
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pass
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def get_secret_and_orig(url):
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frontoffice_url = get_publisher().get_frontoffice_url()
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orig = urllib.parse.urlparse(frontoffice_url).netloc.rsplit('@', 1)[-1].rsplit(':', 1)[0]
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target_orig = urllib.parse.urlparse(url).netloc.rsplit('@', 1)[-1].rsplit(':', 1)[0]
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secret = get_publisher().get_site_option(target_orig, 'wscall-secrets')
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if not secret:
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raise MissingSecret()
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return secret, orig
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def sign_url_auto_orig(url):
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try:
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signature_key, orig = get_secret_and_orig(url)
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except MissingSecret:
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return url
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parsed = urllib.parse.urlparse(url)
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querystring = urllib.parse.parse_qsl(parsed.query)
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querystring.append(('orig', orig))
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querystring = urllib.parse.urlencode(querystring)
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url = urllib.parse.urlunparse(parsed[:4] + (querystring,) + parsed[5:6])
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return sign_url(url, signature_key)
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def get_query_flag(flag, default=False):
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value = get_request().form.get(flag)
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if value in (True, 'True', 'true', 'on', '1'):
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return True
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if value in (False, 'False', 'false', 'off', '0'):
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return False
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return default
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