mirror of
https://github.com/encode/django-rest-framework.git
synced 2024-09-21 11:29:01 +03:00
373 lines
14 KiB
Python
373 lines
14 KiB
Python
"""
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The :mod:`compat` module provides support for backwards compatibility with older versions of django/python.
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"""
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import django
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# cStringIO only if it's available, otherwise StringIO
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try:
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import cStringIO as StringIO
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except ImportError:
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import StringIO
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# First implementation of Django class-based views did not include head method
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# in base View class - https://code.djangoproject.com/ticket/15668
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if django.VERSION >= (1, 4):
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from django.views.generic import View
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else:
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from django.views.generic import View as _View
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from django.utils.decorators import classonlymethod
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from django.utils.functional import update_wrapper
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class View(_View):
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@classonlymethod
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def as_view(cls, **initkwargs):
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"""
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Main entry point for a request-response process.
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"""
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# sanitize keyword arguments
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for key in initkwargs:
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if key in cls.http_method_names:
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raise TypeError(u"You tried to pass in the %s method name as a "
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u"keyword argument to %s(). Don't do that."
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% (key, cls.__name__))
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if not hasattr(cls, key):
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raise TypeError(u"%s() received an invalid keyword %r" % (
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cls.__name__, key))
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def view(request, *args, **kwargs):
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self = cls(**initkwargs)
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if hasattr(self, 'get') and not hasattr(self, 'head'):
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self.head = self.get
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return self.dispatch(request, *args, **kwargs)
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# take name and docstring from class
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update_wrapper(view, cls, updated=())
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# and possible attributes set by decorators
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# like csrf_exempt from dispatch
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update_wrapper(view, cls.dispatch, assigned=())
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return view
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# PUT, DELETE do not require CSRF until 1.4. They should. Make it better.
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if django.VERSION >= (1, 4):
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from django.middleware.csrf import CsrfViewMiddleware
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else:
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import hashlib
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import re
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import random
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import logging
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import urlparse
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from django.conf import settings
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from django.core.urlresolvers import get_callable
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try:
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from logging import NullHandler
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except ImportError:
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class NullHandler(logging.Handler):
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def emit(self, record):
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pass
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logger = logging.getLogger('django.request')
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if not logger.handlers:
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logger.addHandler(NullHandler())
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def same_origin(url1, url2):
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"""
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Checks if two URLs are 'same-origin'
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"""
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p1, p2 = urlparse.urlparse(url1), urlparse.urlparse(url2)
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return p1[0:2] == p2[0:2]
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def constant_time_compare(val1, val2):
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"""
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Returns True if the two strings are equal, False otherwise.
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The time taken is independent of the number of characters that match.
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"""
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if len(val1) != len(val2):
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return False
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result = 0
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for x, y in zip(val1, val2):
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result |= ord(x) ^ ord(y)
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return result == 0
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# Use the system (hardware-based) random number generator if it exists.
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if hasattr(random, 'SystemRandom'):
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randrange = random.SystemRandom().randrange
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else:
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randrange = random.randrange
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_MAX_CSRF_KEY = 18446744073709551616L # 2 << 63
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REASON_NO_REFERER = "Referer checking failed - no Referer."
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REASON_BAD_REFERER = "Referer checking failed - %s does not match %s."
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REASON_NO_CSRF_COOKIE = "CSRF cookie not set."
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REASON_BAD_TOKEN = "CSRF token missing or incorrect."
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def _get_failure_view():
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"""
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Returns the view to be used for CSRF rejections
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"""
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return get_callable(settings.CSRF_FAILURE_VIEW)
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def _get_new_csrf_key():
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return hashlib.md5("%s%s" % (randrange(0, _MAX_CSRF_KEY), settings.SECRET_KEY)).hexdigest()
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def get_token(request):
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"""
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Returns the the CSRF token required for a POST form. The token is an
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alphanumeric value.
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A side effect of calling this function is to make the the csrf_protect
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decorator and the CsrfViewMiddleware add a CSRF cookie and a 'Vary: Cookie'
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header to the outgoing response. For this reason, you may need to use this
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function lazily, as is done by the csrf context processor.
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"""
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request.META["CSRF_COOKIE_USED"] = True
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return request.META.get("CSRF_COOKIE", None)
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def _sanitize_token(token):
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# Allow only alphanum, and ensure we return a 'str' for the sake of the post
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# processing middleware.
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token = re.sub('[^a-zA-Z0-9]', '', str(token.decode('ascii', 'ignore')))
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if token == "":
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# In case the cookie has been truncated to nothing at some point.
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return _get_new_csrf_key()
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else:
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return token
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class CsrfViewMiddleware(object):
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"""
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Middleware that requires a present and correct csrfmiddlewaretoken
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for POST requests that have a CSRF cookie, and sets an outgoing
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CSRF cookie.
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This middleware should be used in conjunction with the csrf_token template
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tag.
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"""
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# The _accept and _reject methods currently only exist for the sake of the
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# requires_csrf_token decorator.
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def _accept(self, request):
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# Avoid checking the request twice by adding a custom attribute to
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# request. This will be relevant when both decorator and middleware
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# are used.
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request.csrf_processing_done = True
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return None
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def _reject(self, request, reason):
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return _get_failure_view()(request, reason=reason)
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def process_view(self, request, callback, callback_args, callback_kwargs):
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if getattr(request, 'csrf_processing_done', False):
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return None
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try:
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csrf_token = _sanitize_token(request.COOKIES[settings.CSRF_COOKIE_NAME])
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# Use same token next time
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request.META['CSRF_COOKIE'] = csrf_token
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except KeyError:
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csrf_token = None
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# Generate token and store it in the request, so it's available to the view.
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request.META["CSRF_COOKIE"] = _get_new_csrf_key()
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# Wait until request.META["CSRF_COOKIE"] has been manipulated before
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# bailing out, so that get_token still works
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if getattr(callback, 'csrf_exempt', False):
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return None
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# Assume that anything not defined as 'safe' by RC2616 needs protection.
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if request.method not in ('GET', 'HEAD', 'OPTIONS', 'TRACE'):
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if getattr(request, '_dont_enforce_csrf_checks', False):
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# Mechanism to turn off CSRF checks for test suite. It comes after
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# the creation of CSRF cookies, so that everything else continues to
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# work exactly the same (e.g. cookies are sent etc), but before the
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# any branches that call reject()
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return self._accept(request)
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if request.is_secure():
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# Suppose user visits http://example.com/
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# An active network attacker,(man-in-the-middle, MITM) sends a
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# POST form which targets https://example.com/detonate-bomb/ and
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# submits it via javascript.
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#
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# The attacker will need to provide a CSRF cookie and token, but
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# that is no problem for a MITM and the session independent
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# nonce we are using. So the MITM can circumvent the CSRF
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# protection. This is true for any HTTP connection, but anyone
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# using HTTPS expects better! For this reason, for
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# https://example.com/ we need additional protection that treats
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# http://example.com/ as completely untrusted. Under HTTPS,
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# Barth et al. found that the Referer header is missing for
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# same-domain requests in only about 0.2% of cases or less, so
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# we can use strict Referer checking.
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referer = request.META.get('HTTP_REFERER')
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if referer is None:
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logger.warning('Forbidden (%s): %s' % (REASON_NO_REFERER, request.path),
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extra={
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'status_code': 403,
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'request': request,
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}
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)
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return self._reject(request, REASON_NO_REFERER)
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# Note that request.get_host() includes the port
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good_referer = 'https://%s/' % request.get_host()
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if not same_origin(referer, good_referer):
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reason = REASON_BAD_REFERER % (referer, good_referer)
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logger.warning('Forbidden (%s): %s' % (reason, request.path),
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extra={
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'status_code': 403,
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'request': request,
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}
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)
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return self._reject(request, reason)
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if csrf_token is None:
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# No CSRF cookie. For POST requests, we insist on a CSRF cookie,
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# and in this way we can avoid all CSRF attacks, including login
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# CSRF.
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logger.warning('Forbidden (%s): %s' % (REASON_NO_CSRF_COOKIE, request.path),
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extra={
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'status_code': 403,
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'request': request,
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}
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)
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return self._reject(request, REASON_NO_CSRF_COOKIE)
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# check non-cookie token for match
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request_csrf_token = ""
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if request.method == "POST":
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request_csrf_token = request.POST.get('csrfmiddlewaretoken', '')
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if request_csrf_token == "":
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# Fall back to X-CSRFToken, to make things easier for AJAX,
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# and possible for PUT/DELETE
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request_csrf_token = request.META.get('HTTP_X_CSRFTOKEN', '')
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if not constant_time_compare(request_csrf_token, csrf_token):
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logger.warning('Forbidden (%s): %s' % (REASON_BAD_TOKEN, request.path),
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extra={
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'status_code': 403,
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'request': request,
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}
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)
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return self._reject(request, REASON_BAD_TOKEN)
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return self._accept(request)
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# timezone support is new in Django 1.4
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try:
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from django.utils import timezone
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except ImportError:
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timezone = None
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# dateparse is ALSO new in Django 1.4
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try:
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from django.utils.dateparse import parse_date, parse_datetime
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except ImportError:
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import datetime
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import re
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date_re = re.compile(
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r'(?P<year>\d{4})-(?P<month>\d{1,2})-(?P<day>\d{1,2})$'
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)
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datetime_re = re.compile(
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r'(?P<year>\d{4})-(?P<month>\d{1,2})-(?P<day>\d{1,2})'
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r'[T ](?P<hour>\d{1,2}):(?P<minute>\d{1,2})'
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r'(?::(?P<second>\d{1,2})(?:\.(?P<microsecond>\d{1,6})\d{0,6})?)?'
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r'(?P<tzinfo>Z|[+-]\d{1,2}:\d{1,2})?$'
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)
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time_re = re.compile(
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r'(?P<hour>\d{1,2}):(?P<minute>\d{1,2})'
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r'(?::(?P<second>\d{1,2})(?:\.(?P<microsecond>\d{1,6})\d{0,6})?)?'
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)
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def parse_date(value):
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match = date_re.match(value)
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if match:
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kw = dict((k, int(v)) for k, v in match.groupdict().iteritems())
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return datetime.date(**kw)
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def parse_time(value):
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match = time_re.match(value)
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if match:
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kw = match.groupdict()
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if kw['microsecond']:
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kw['microsecond'] = kw['microsecond'].ljust(6, '0')
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kw = dict((k, int(v)) for k, v in kw.iteritems() if v is not None)
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return datetime.time(**kw)
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def parse_datetime(value):
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"""Parse datetime, but w/o the timezone awareness in 1.4"""
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match = datetime_re.match(value)
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if match:
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kw = match.groupdict()
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if kw['microsecond']:
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kw['microsecond'] = kw['microsecond'].ljust(6, '0')
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kw = dict((k, int(v)) for k, v in kw.iteritems() if v is not None)
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return datetime.datetime(**kw)
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# Markdown is optional
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try:
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import markdown
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def apply_markdown(text):
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"""
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Simple wrapper around :func:`markdown.markdown` to set the base level
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of '#' style headers to <h2>.
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"""
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extensions = ['headerid(level=2)']
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safe_mode = False,
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md = markdown.Markdown(extensions=extensions, safe_mode=safe_mode)
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return md.convert(text)
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except ImportError:
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apply_markdown = None
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# Yaml is optional
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try:
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import yaml
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except ImportError:
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yaml = None
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import unittest
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try:
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import unittest.skip
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except ImportError: # python < 2.7
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from unittest import TestCase
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import functools
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def skip(reason):
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# Pasted from py27/lib/unittest/case.py
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"""
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Unconditionally skip a test.
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"""
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def decorator(test_item):
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if not (isinstance(test_item, type) and issubclass(test_item, TestCase)):
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@functools.wraps(test_item)
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def skip_wrapper(*args, **kwargs):
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pass
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test_item = skip_wrapper
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test_item.__unittest_skip__ = True
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test_item.__unittest_skip_why__ = reason
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return test_item
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return decorator
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unittest.skip = skip
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# xml.etree.parse only throws ParseError for python >= 2.7
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try:
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from xml.etree import ParseError as ETParseError
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except ImportError: # python < 2.7
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ETParseError = None
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