django-rest-framework/rest_framework/compat.py

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"""
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The `compat` module provides support for backwards compatibility with older
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versions of django/python, and compatibility wrappers around optional packages.
"""
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# flake8: noqa
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from __future__ import unicode_literals
import django
import inspect
from django.core.exceptions import ImproperlyConfigured
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from django.conf import settings
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# Try to import six from Django, fallback to included `six`.
try:
from django.utils import six
except ImportError:
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from rest_framework import six
# location of patterns, url, include changes in 1.4 onwards
try:
from django.conf.urls import patterns, url, include
except ImportError:
from django.conf.urls.defaults import patterns, url, include
# Handle django.utils.encoding rename:
# smart_unicode -> smart_text
# force_unicode -> force_text
try:
from django.utils.encoding import smart_text
except ImportError:
from django.utils.encoding import smart_unicode as smart_text
try:
from django.utils.encoding import force_text
except ImportError:
from django.utils.encoding import force_unicode as force_text
# HttpResponseBase only exists from 1.5 onwards
try:
from django.http.response import HttpResponseBase
except ImportError:
from django.http import HttpResponse as HttpResponseBase
# django-filter is optional
try:
import django_filters
except ImportError:
django_filters = None
# guardian is optional
try:
import guardian
except ImportError:
guardian = None
# cStringIO only if it's available, otherwise StringIO
try:
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import cStringIO.StringIO as StringIO
except ImportError:
StringIO = six.StringIO
BytesIO = six.BytesIO
# urlparse compat import (Required because it changed in python 3.x)
try:
from urllib import parse as urlparse
except ImportError:
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import urlparse
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# UserDict moves in Python 3
try:
from UserDict import UserDict
from UserDict import DictMixin
except ImportError:
from collections import UserDict
from collections import MutableMapping as DictMixin
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# Try to import PIL in either of the two ways it can end up installed.
try:
from PIL import Image
except ImportError:
try:
import Image
except ImportError:
Image = None
def get_model_name(model_cls):
try:
return model_cls._meta.model_name
except AttributeError:
# < 1.6 used module_name instead of model_name
return model_cls._meta.module_name
def get_concrete_model(model_cls):
try:
return model_cls._meta.concrete_model
except AttributeError:
# 1.3 does not include concrete model
return model_cls
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if django.VERSION >= (1, 5):
from django.views.generic import View
else:
from django.views.generic import View as _View
from django.utils.decorators import classonlymethod
from django.utils.functional import update_wrapper
class View(_View):
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# 1.3 does not include head method in base View class
# See: https://code.djangoproject.com/ticket/15668
@classonlymethod
def as_view(cls, **initkwargs):
"""
Main entry point for a request-response process.
"""
# sanitize keyword arguments
for key in initkwargs:
if key in cls.http_method_names:
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raise TypeError("You tried to pass in the %s method name as a "
"keyword argument to %s(). Don't do that."
% (key, cls.__name__))
if not hasattr(cls, key):
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raise TypeError("%s() received an invalid keyword %r" % (
cls.__name__, key))
def view(request, *args, **kwargs):
self = cls(**initkwargs)
if hasattr(self, 'get') and not hasattr(self, 'head'):
self.head = self.get
return self.dispatch(request, *args, **kwargs)
# take name and docstring from class
update_wrapper(view, cls, updated=())
# and possible attributes set by decorators
# like csrf_exempt from dispatch
update_wrapper(view, cls.dispatch, assigned=())
return view
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# _allowed_methods only present from 1.5 onwards
def _allowed_methods(self):
return [m.upper() for m in self.http_method_names if hasattr(self, m)]
# PATCH method is not implemented by Django
if 'patch' not in View.http_method_names:
View.http_method_names = View.http_method_names + ['patch']
# PUT, DELETE do not require CSRF until 1.4. They should. Make it better.
if django.VERSION >= (1, 4):
from django.middleware.csrf import CsrfViewMiddleware
else:
import hashlib
import re
import random
import logging
from django.conf import settings
from django.core.urlresolvers import get_callable
try:
from logging import NullHandler
except ImportError:
class NullHandler(logging.Handler):
def emit(self, record):
pass
logger = logging.getLogger('django.request')
if not logger.handlers:
logger.addHandler(NullHandler())
def same_origin(url1, url2):
"""
Checks if two URLs are 'same-origin'
"""
p1, p2 = urlparse.urlparse(url1), urlparse.urlparse(url2)
return p1[0:2] == p2[0:2]
def constant_time_compare(val1, val2):
"""
Returns True if the two strings are equal, False otherwise.
The time taken is independent of the number of characters that match.
"""
if len(val1) != len(val2):
return False
result = 0
for x, y in zip(val1, val2):
result |= ord(x) ^ ord(y)
return result == 0
# Use the system (hardware-based) random number generator if it exists.
if hasattr(random, 'SystemRandom'):
randrange = random.SystemRandom().randrange
else:
randrange = random.randrange
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_MAX_CSRF_KEY = 18446744073709551616 # 2 << 63
REASON_NO_REFERER = "Referer checking failed - no Referer."
REASON_BAD_REFERER = "Referer checking failed - %s does not match %s."
REASON_NO_CSRF_COOKIE = "CSRF cookie not set."
REASON_BAD_TOKEN = "CSRF token missing or incorrect."
def _get_failure_view():
"""
Returns the view to be used for CSRF rejections
"""
return get_callable(settings.CSRF_FAILURE_VIEW)
def _get_new_csrf_key():
return hashlib.md5("%s%s" % (randrange(0, _MAX_CSRF_KEY), settings.SECRET_KEY)).hexdigest()
def get_token(request):
"""
Returns the the CSRF token required for a POST form. The token is an
alphanumeric value.
A side effect of calling this function is to make the the csrf_protect
decorator and the CsrfViewMiddleware add a CSRF cookie and a 'Vary: Cookie'
header to the outgoing response. For this reason, you may need to use this
function lazily, as is done by the csrf context processor.
"""
request.META["CSRF_COOKIE_USED"] = True
return request.META.get("CSRF_COOKIE", None)
def _sanitize_token(token):
# Allow only alphanum, and ensure we return a 'str' for the sake of the post
# processing middleware.
token = re.sub('[^a-zA-Z0-9]', '', str(token.decode('ascii', 'ignore')))
if token == "":
# In case the cookie has been truncated to nothing at some point.
return _get_new_csrf_key()
else:
return token
class CsrfViewMiddleware(object):
"""
Middleware that requires a present and correct csrfmiddlewaretoken
for POST requests that have a CSRF cookie, and sets an outgoing
CSRF cookie.
This middleware should be used in conjunction with the csrf_token template
tag.
"""
# The _accept and _reject methods currently only exist for the sake of the
# requires_csrf_token decorator.
def _accept(self, request):
# Avoid checking the request twice by adding a custom attribute to
# request. This will be relevant when both decorator and middleware
# are used.
request.csrf_processing_done = True
return None
def _reject(self, request, reason):
return _get_failure_view()(request, reason=reason)
def process_view(self, request, callback, callback_args, callback_kwargs):
if getattr(request, 'csrf_processing_done', False):
return None
try:
csrf_token = _sanitize_token(request.COOKIES[settings.CSRF_COOKIE_NAME])
# Use same token next time
request.META['CSRF_COOKIE'] = csrf_token
except KeyError:
csrf_token = None
# Generate token and store it in the request, so it's available to the view.
request.META["CSRF_COOKIE"] = _get_new_csrf_key()
# Wait until request.META["CSRF_COOKIE"] has been manipulated before
# bailing out, so that get_token still works
if getattr(callback, 'csrf_exempt', False):
return None
# Assume that anything not defined as 'safe' by RC2616 needs protection.
if request.method not in ('GET', 'HEAD', 'OPTIONS', 'TRACE'):
if getattr(request, '_dont_enforce_csrf_checks', False):
# Mechanism to turn off CSRF checks for test suite. It comes after
# the creation of CSRF cookies, so that everything else continues to
# work exactly the same (e.g. cookies are sent etc), but before the
# any branches that call reject()
return self._accept(request)
if request.is_secure():
# Suppose user visits http://example.com/
# An active network attacker,(man-in-the-middle, MITM) sends a
# POST form which targets https://example.com/detonate-bomb/ and
# submits it via javascript.
#
# The attacker will need to provide a CSRF cookie and token, but
# that is no problem for a MITM and the session independent
# nonce we are using. So the MITM can circumvent the CSRF
# protection. This is true for any HTTP connection, but anyone
# using HTTPS expects better! For this reason, for
# https://example.com/ we need additional protection that treats
# http://example.com/ as completely untrusted. Under HTTPS,
# Barth et al. found that the Referer header is missing for
# same-domain requests in only about 0.2% of cases or less, so
# we can use strict Referer checking.
referer = request.META.get('HTTP_REFERER')
if referer is None:
logger.warning('Forbidden (%s): %s' % (REASON_NO_REFERER, request.path),
extra={
'status_code': 403,
'request': request,
}
)
return self._reject(request, REASON_NO_REFERER)
# Note that request.get_host() includes the port
good_referer = 'https://%s/' % request.get_host()
if not same_origin(referer, good_referer):
reason = REASON_BAD_REFERER % (referer, good_referer)
logger.warning('Forbidden (%s): %s' % (reason, request.path),
extra={
'status_code': 403,
'request': request,
}
)
return self._reject(request, reason)
if csrf_token is None:
# No CSRF cookie. For POST requests, we insist on a CSRF cookie,
# and in this way we can avoid all CSRF attacks, including login
# CSRF.
logger.warning('Forbidden (%s): %s' % (REASON_NO_CSRF_COOKIE, request.path),
extra={
'status_code': 403,
'request': request,
}
)
return self._reject(request, REASON_NO_CSRF_COOKIE)
# check non-cookie token for match
request_csrf_token = ""
if request.method == "POST":
request_csrf_token = request.POST.get('csrfmiddlewaretoken', '')
if request_csrf_token == "":
# Fall back to X-CSRFToken, to make things easier for AJAX,
# and possible for PUT/DELETE
request_csrf_token = request.META.get('HTTP_X_CSRFTOKEN', '')
if not constant_time_compare(request_csrf_token, csrf_token):
logger.warning('Forbidden (%s): %s' % (REASON_BAD_TOKEN, request.path),
extra={
'status_code': 403,
'request': request,
}
)
return self._reject(request, REASON_BAD_TOKEN)
return self._accept(request)
# timezone support is new in Django 1.4
try:
from django.utils import timezone
except ImportError:
timezone = None
# dateparse is ALSO new in Django 1.4
try:
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from django.utils.dateparse import parse_date, parse_datetime, parse_time
except ImportError:
import datetime
import re
date_re = re.compile(
r'(?P<year>\d{4})-(?P<month>\d{1,2})-(?P<day>\d{1,2})$'
)
datetime_re = re.compile(
r'(?P<year>\d{4})-(?P<month>\d{1,2})-(?P<day>\d{1,2})'
r'[T ](?P<hour>\d{1,2}):(?P<minute>\d{1,2})'
r'(?::(?P<second>\d{1,2})(?:\.(?P<microsecond>\d{1,6})\d{0,6})?)?'
r'(?P<tzinfo>Z|[+-]\d{1,2}:\d{1,2})?$'
)
time_re = re.compile(
r'(?P<hour>\d{1,2}):(?P<minute>\d{1,2})'
r'(?::(?P<second>\d{1,2})(?:\.(?P<microsecond>\d{1,6})\d{0,6})?)?'
)
def parse_date(value):
match = date_re.match(value)
if match:
kw = dict((k, int(v)) for k, v in match.groupdict().iteritems())
return datetime.date(**kw)
def parse_time(value):
match = time_re.match(value)
if match:
kw = match.groupdict()
if kw['microsecond']:
kw['microsecond'] = kw['microsecond'].ljust(6, '0')
kw = dict((k, int(v)) for k, v in kw.iteritems() if v is not None)
return datetime.time(**kw)
def parse_datetime(value):
"""Parse datetime, but w/o the timezone awareness in 1.4"""
match = datetime_re.match(value)
if match:
kw = match.groupdict()
if kw['microsecond']:
kw['microsecond'] = kw['microsecond'].ljust(6, '0')
kw = dict((k, int(v)) for k, v in kw.iteritems() if v is not None)
return datetime.datetime(**kw)
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# smart_urlquote is new on Django 1.4
try:
from django.utils.html import smart_urlquote
except ImportError:
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import re
from django.utils.encoding import smart_str
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try:
from urllib.parse import quote, urlsplit, urlunsplit
except ImportError: # Python 2
from urllib import quote
from urlparse import urlsplit, urlunsplit
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unquoted_percents_re = re.compile(r'%(?![0-9A-Fa-f]{2})')
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def smart_urlquote(url):
"Quotes a URL if it isn't already quoted."
# Handle IDN before quoting.
scheme, netloc, path, query, fragment = urlsplit(url)
try:
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netloc = netloc.encode('idna').decode('ascii') # IDN -> ACE
except UnicodeError: # invalid domain part
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pass
else:
url = urlunsplit((scheme, netloc, path, query, fragment))
# An URL is considered unquoted if it contains no % characters or
# contains a % not followed by two hexadecimal digits. See #9655.
if '%' not in url or unquoted_percents_re.search(url):
# See http://bugs.python.org/issue2637
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url = quote(smart_str(url), safe=b'!*\'();:@&=+$,/?#[]~')
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return force_text(url)
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# RequestFactory only provide `generic` from 1.5 onwards
from django.test.client import RequestFactory as DjangoRequestFactory
from django.test.client import FakePayload
try:
# In 1.5 the test client uses force_bytes
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from django.utils.encoding import force_bytes as force_bytes_or_smart_bytes
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except ImportError:
# In 1.3 and 1.4 the test client just uses smart_str
from django.utils.encoding import smart_str as force_bytes_or_smart_bytes
class RequestFactory(DjangoRequestFactory):
def generic(self, method, path,
data='', content_type='application/octet-stream', **extra):
parsed = urlparse.urlparse(path)
data = force_bytes_or_smart_bytes(data, settings.DEFAULT_CHARSET)
r = {
'PATH_INFO': self._get_path(parsed),
'QUERY_STRING': force_text(parsed[4]),
'REQUEST_METHOD': str(method),
}
if data:
r.update({
'CONTENT_LENGTH': len(data),
'CONTENT_TYPE': str(content_type),
'wsgi.input': FakePayload(data),
})
elif django.VERSION <= (1, 4):
# For 1.3 we need an empty WSGI payload
r.update({
'wsgi.input': FakePayload('')
})
r.update(extra)
return self.request(**r)
# Markdown is optional
try:
import markdown
def apply_markdown(text):
"""
Simple wrapper around :func:`markdown.markdown` to set the base level
of '#' style headers to <h2>.
"""
extensions = ['headerid(level=2)']
safe_mode = False
md = markdown.Markdown(extensions=extensions, safe_mode=safe_mode)
return md.convert(text)
except ImportError:
apply_markdown = None
# Yaml is optional
try:
import yaml
except ImportError:
yaml = None
# XML is optional
try:
import defusedxml.ElementTree as etree
except ImportError:
etree = None
# OAuth is optional
try:
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# Note: The `oauth2` package actually provides oauth1.0a support. Urg.
import oauth2 as oauth
except ImportError:
oauth = None
# OAuth is optional
try:
import oauth_provider
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from oauth_provider.store import store as oauth_provider_store
# check_nonce's calling signature in django-oauth-plus changes sometime
# between versions 2.0 and 2.2.1
def check_nonce(request, oauth_request, oauth_nonce, oauth_timestamp):
check_nonce_args = inspect.getargspec(oauth_provider_store.check_nonce).args
if 'timestamp' in check_nonce_args:
return oauth_provider_store.check_nonce(
request, oauth_request, oauth_nonce, oauth_timestamp
)
return oauth_provider_store.check_nonce(
request, oauth_request, oauth_nonce
)
except (ImportError, ImproperlyConfigured):
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oauth_provider = None
oauth_provider_store = None
check_nonce = None
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# OAuth 2 support is optional
try:
import provider.oauth2 as oauth2_provider
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from provider.oauth2 import models as oauth2_provider_models
from provider.oauth2 import forms as oauth2_provider_forms
from provider import scope as oauth2_provider_scope
from provider import constants as oauth2_constants
from provider import __version__ as provider_version
if provider_version in ('0.2.3', '0.2.4'):
# 0.2.3 and 0.2.4 are supported version that do not support
# timezone aware datetimes
import datetime
provider_now = datetime.datetime.now
else:
# Any other supported version does use timezone aware datetimes
from django.utils.timezone import now as provider_now
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except ImportError:
oauth2_provider = None
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oauth2_provider_models = None
oauth2_provider_forms = None
oauth2_provider_scope = None
oauth2_constants = None
provider_now = None
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# Handle lazy strings
from django.utils.functional import Promise
if six.PY3:
def is_non_str_iterable(obj):
if (isinstance(obj, str) or
(isinstance(obj, Promise) and obj._delegate_text)):
return False
return hasattr(obj, '__iter__')
else:
def is_non_str_iterable(obj):
return hasattr(obj, '__iter__')
try:
from django.utils.encoding import python_2_unicode_compatible
except ImportError:
def python_2_unicode_compatible(klass):
"""
A decorator that defines __unicode__ and __str__ methods under Python 2.
Under Python 3 it does nothing.
To support Python 2 and 3 with a single code base, define a __str__ method
returning text and apply this decorator to the class.
"""
if '__str__' not in klass.__dict__:
raise ValueError("@python_2_unicode_compatible cannot be applied "
"to %s because it doesn't define __str__()." %
klass.__name__)
klass.__unicode__ = klass.__str__
klass.__str__ = lambda self: self.__unicode__().encode('utf-8')
return klass