66 lines
2.2 KiB
Python
66 lines
2.2 KiB
Python
# combo - content management system
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# Copyright (C) 2015 Entr'ouvert
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#
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# This program is free software: you can redistribute it and/or modify it
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# under the terms of the GNU Affero General Public License as published
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# by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import datetime
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import base64
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import hmac
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import hashlib
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from HTMLParser import HTMLParser
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import urllib
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import random
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import urlparse
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from django.utils.html import strip_tags
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class NothingInCacheException(Exception):
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pass
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'''Simple signature scheme for query strings'''
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def sign_url(url, key, algo='sha256', timestamp=None, nonce=None):
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parsed = urlparse.urlparse(url)
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new_query = sign_query(parsed.query, key, algo, timestamp, nonce)
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return urlparse.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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nonce = hex(random.getrandbits(128))[2:]
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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.urlencode((
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('algo', algo),
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('timestamp', timestamp),
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('nonce', nonce)))
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signature = base64.b64encode(sign_string(new_query, key, algo=algo))
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new_query += '&signature=' + urllib.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(key, digestmod=digestmod, msg=s)
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return hash.digest()
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def ellipsize(text, length=50):
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text = HTMLParser().unescape(strip_tags(text))
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if len(text) < length:
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return text
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return text[:(length-10)] + '...'
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