189 lines
7.6 KiB
Python
189 lines
7.6 KiB
Python
import logging
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import re
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from django import http
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from django.conf import settings
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from django.core.exceptions import PermissionDenied
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from django.core.mail import mail_managers
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from django.urls import is_valid_path
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from django.utils.cache import get_conditional_response, set_response_etag
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from django.utils.encoding import force_text
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from django.utils.http import unquote_etag
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from django.utils.six.moves.urllib.parse import urlparse
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logger = logging.getLogger('django.request')
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class CommonMiddleware(object):
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"""
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"Common" middleware for taking care of some basic operations:
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- Forbids access to User-Agents in settings.DISALLOWED_USER_AGENTS
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- URL rewriting: Based on the APPEND_SLASH and PREPEND_WWW settings,
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this middleware appends missing slashes and/or prepends missing
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"www."s.
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- If APPEND_SLASH is set and the initial URL doesn't end with a
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slash, and it is not found in urlpatterns, a new URL is formed by
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appending a slash at the end. If this new URL is found in
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urlpatterns, then an HTTP-redirect is returned to this new URL;
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otherwise the initial URL is processed as usual.
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This behavior can be customized by subclassing CommonMiddleware and
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overriding the response_redirect_class attribute.
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- ETags: If the USE_ETAGS setting is set, ETags will be calculated from
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the entire page content and Not Modified responses will be returned
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appropriately.
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"""
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response_redirect_class = http.HttpResponsePermanentRedirect
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def process_request(self, request):
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"""
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Check for denied User-Agents and rewrite the URL based on
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settings.APPEND_SLASH and settings.PREPEND_WWW
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"""
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# Check for denied User-Agents
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if 'HTTP_USER_AGENT' in request.META:
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for user_agent_regex in settings.DISALLOWED_USER_AGENTS:
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if user_agent_regex.search(request.META['HTTP_USER_AGENT']):
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raise PermissionDenied('Forbidden user agent')
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# Check for a redirect based on settings.PREPEND_WWW
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host = request.get_host()
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must_prepend = settings.PREPEND_WWW and host and not host.startswith('www.')
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redirect_url = ('%s://www.%s' % (request.scheme, host)) if must_prepend else ''
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# Check if a slash should be appended
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if self.should_redirect_with_slash(request):
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path = self.get_full_path_with_slash(request)
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else:
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path = request.get_full_path()
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# Return a redirect if necessary
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if redirect_url or path != request.get_full_path():
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redirect_url += path
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return self.response_redirect_class(redirect_url)
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def should_redirect_with_slash(self, request):
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"""
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Return True if settings.APPEND_SLASH is True and appending a slash to
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the request path turns an invalid path into a valid one.
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"""
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if settings.APPEND_SLASH and not request.get_full_path().endswith('/'):
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urlconf = getattr(request, 'urlconf', None)
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return (
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not is_valid_path(request.path_info, urlconf) and
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is_valid_path('%s/' % request.path_info, urlconf)
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)
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return False
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def get_full_path_with_slash(self, request):
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"""
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Return the full path of the request with a trailing slash appended.
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Raise a RuntimeError if settings.DEBUG is True and request.method is
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POST, PUT, or PATCH.
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"""
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new_path = request.get_full_path(force_append_slash=True)
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if settings.DEBUG and request.method in ('POST', 'PUT', 'PATCH'):
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raise RuntimeError(
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"You called this URL via %(method)s, but the URL doesn't end "
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"in a slash and you have APPEND_SLASH set. Django can't "
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"redirect to the slash URL while maintaining %(method)s data. "
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"Change your form to point to %(url)s (note the trailing "
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"slash), or set APPEND_SLASH=False in your Django settings." % {
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'method': request.method,
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'url': request.get_host() + new_path,
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}
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)
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return new_path
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def process_response(self, request, response):
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"""
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Calculate the ETag, if needed.
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When the status code of the response is 404, it may redirect to a path
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with an appended slash if should_redirect_with_slash() returns True.
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"""
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# If the given URL is "Not Found", then check if we should redirect to
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# a path with a slash appended.
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if response.status_code == 404:
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if self.should_redirect_with_slash(request):
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return self.response_redirect_class(self.get_full_path_with_slash(request))
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if settings.USE_ETAGS:
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if not response.has_header('ETag'):
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set_response_etag(response)
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if response.has_header('ETag'):
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return get_conditional_response(
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request,
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etag=unquote_etag(response['ETag']),
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response=response,
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)
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return response
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class BrokenLinkEmailsMiddleware(object):
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def process_response(self, request, response):
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"""
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Send broken link emails for relevant 404 NOT FOUND responses.
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"""
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if response.status_code == 404 and not settings.DEBUG:
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domain = request.get_host()
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path = request.get_full_path()
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referer = force_text(request.META.get('HTTP_REFERER', ''), errors='replace')
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if not self.is_ignorable_request(request, path, domain, referer):
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ua = force_text(request.META.get('HTTP_USER_AGENT', '<none>'), errors='replace')
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ip = request.META.get('REMOTE_ADDR', '<none>')
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mail_managers(
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"Broken %slink on %s" % (
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('INTERNAL ' if self.is_internal_request(domain, referer) else ''),
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domain
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),
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"Referrer: %s\nRequested URL: %s\nUser agent: %s\n"
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"IP address: %s\n" % (referer, path, ua, ip),
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fail_silently=True)
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return response
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def is_internal_request(self, domain, referer):
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"""
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Returns True if the referring URL is the same domain as the current request.
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"""
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# Different subdomains are treated as different domains.
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return bool(re.match("^https?://%s/" % re.escape(domain), referer))
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def is_ignorable_request(self, request, uri, domain, referer):
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"""
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Return True if the given request *shouldn't* notify the site managers
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according to project settings or in situations outlined by the inline
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comments.
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"""
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# The referer is empty.
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if not referer:
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return True
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# APPEND_SLASH is enabled and the referer is equal to the current URL
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# without a trailing slash indicating an internal redirect.
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if settings.APPEND_SLASH and uri.endswith('/') and referer == uri[:-1]:
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return True
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# A '?' in referer is identified as a search engine source.
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if not self.is_internal_request(domain, referer) and '?' in referer:
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return True
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# The referer is equal to the current URL, ignoring the scheme (assumed
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# to be a poorly implemented bot).
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parsed_referer = urlparse(referer)
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if parsed_referer.netloc in ['', domain] and parsed_referer.path == uri:
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return True
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return any(pattern.search(uri) for pattern in settings.IGNORABLE_404_URLS)
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