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# Copyright 2008 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import base64
import hashlib
import hmac
import logging
import os
import time
import urllib
from google.appengine.api import users
from google.appengine.runtime import DeadlineExceededError
import django
from django.template import loader as template_loader
from django.http import HttpResponse, \
HttpResponseRedirect, \
HttpResponseForbidden, \
HttpResponseNotFound
from django.forms import ValidationError
# Add our own template library.
_library_name = __name__.rsplit('.', 1)[0] + '.library'
if not django.template.libraries.get(_library_name, None):
django.template.add_to_builtins(_library_name)
del _library_name
import models
IS_DEV = os.environ['SERVER_SOFTWARE'].startswith('Dev')
MAX_XSRF_WINDOW = 4 * 60 * 60 # seconds
### Decorators for request handlers ###
def login_required(func):
"""Decorator that redirects to the login page if you're not logged in."""
def login_wrapper(request, *args, **kwds):
if request.user is None:
return HttpResponseRedirect(
users.create_login_url(request.get_full_path()))
if not request.account.welcomed and request.path != '/settings/welcome':
return HttpResponseRedirect(
'/settings/welcome?dest=%s' % urllib.quote(request.get_full_path()))
return func(request, *args, **kwds)
return login_wrapper
def gae_admin_required(func):
def admin_wrapper(request, *args, **kwds):
"""Decorator that insists that you are a GAE admin/developer.
"""
if request.user is None:
path = request.get_full_path()
return HttpResponseRedirect(users.create_login_url(path))
if not request.is_gae_admin:
return HttpResponseNotFound('Page not found')
return func(request, *args, **kwds)
return admin_wrapper
def admin_required(func):
def admin_wrapper(request, *args, **kwds):
"""Decorator that insists that you're logged in as administratior."""
if request.user is None:
return HttpResponseRedirect(
users.create_login_url(request.get_full_path()))
if not request.user_is_admin:
return HttpResponseNotFound('Page not found')
return func(request, *args, **kwds)
return admin_wrapper
def project_owner_or_admin_required(func):
def admin_wrapper(request, *args, **kwds):
"""Decorator that insists that you're logged in as administratior."""
if request.user is None:
return HttpResponseRedirect(
users.create_login_url(request.get_full_path()))
if not (request.user_is_admin or request.projects_owned_by_user):
return HttpResponseNotFound('Page not found')
return func(request, *args, **kwds)
return admin_wrapper
def devenv_required(func):
def devenv_wrapper(request, *args, **kwds):
"""Decorator that insists that you're on the development server."""
if not IS_DEV:
return HttpResponseNotFound('Page not found')
return func(request, *args, **kwds)
return devenv_wrapper
def change_required(func):
"""Decorator that processes the change_id handler argument."""
def change_wrapper(request, change_id, *args, **kwds):
change = models.Change.get_by_id(int(change_id))
if change is None:
return HttpResponseNotFound('No change exists with that id (%s)' %
change_id)
request.change = change
return func(request, *args, **kwds)
return change_wrapper
def posted_change_required(func):
"""Decorator that processes POST['change_id']
"""
def change_wrapper(request, *args, **kwds):
try:
change_id = request.POST['change_id']
except KeyError:
return HttpResponseNotFound('No change supplied.')
change = models.Change.get_by_id(int(change_id))
if change is None:
return HttpResponseNotFound('No change exists with that id (%s)' %
change_id)
request.change = change
return func(request, *args, **kwds)
return change_wrapper
def user_key_required(func):
"""Decorator that processes the user handler argument."""
def user_key_wrapper(request, user_key, *args, **kwds):
user_key = urllib.unquote(user_key)
if '@' in user_key:
request.user_to_show = users.User(user_key)
elif ',,' in user_key:
request.user_to_show = users.User(user_key.replace(',,','@'))
else:
accounts = models.Account.get_accounts_for_real_name(user_key)
if not accounts:
logging.info("account not found for real_name %s" % user_key)
return HttpResponseNotFound('No user found with that key (%s)' %
user_key)
request.user_to_show = accounts[0].user
return func(request, *args, **kwds)
return user_key_wrapper
def change_owner_required(func):
"""Decorator that processes the change_id argument and insists you own it."""
@change_required
@login_required
def change_owner_wrapper(request, *args, **kwds):
if request.change.owner != request.user:
return HttpResponseForbidden('You do not own this change')
return func(request, *args, **kwds)
return change_owner_wrapper
def patchset_required(func):
"""Decorator that processes the patchset_id argument."""
@change_required
def patchset_wrapper(request, patchset_id, *args, **kwds):
patchset = models.PatchSet.get_by_id(int(patchset_id), parent=request.change)
if patchset is None:
return HttpResponseNotFound('No patch set exists with that id (%s)' %
patchset_id)
patchset.change = request.change
request.patchset = patchset
return func(request, *args, **kwds)
return patchset_wrapper
def patch_required(func):
"""Decorator that processes the patch_id argument."""
@patchset_required
def patch_wrapper(request, patch_id, *args, **kwds):
patch = models.Patch.get_patch(request.patchset, patch_id)
if patch is None:
return HttpResponseNotFound('No patch exists with that id (%s %s)' %
(request.patchset.key().id(), patch_id))
patch.patchset = request.patchset
request.patch = patch
return func(request, *args, **kwds)
return patch_wrapper
### Render Django template ###
def _parse_template(name):
return template_loader.get_template(name)
def _lookup_template(name):
try:
t = _template_cache[name]
except KeyError:
t = _parse_template(name)
_template_cache[name] = t
return t
_template_cache = {}
if IS_DEV:
_get_template = _parse_template
else:
_get_template = _lookup_template
def respond(request, template, params=None, status=200):
"""Render a response, passing standard stuff to the response.
Args:
request: The request object.
template: The template name; '.html' is appended automatically.
params: A dict giving the template parameters; modified in-place.
Returns:
A Django HttpResponse
"""
try:
if params is None:
params = {}
params['request'] = request
params['user'] = request.user
params['is_gae_admin'] = request.is_gae_admin
params['is_dev'] = IS_DEV
params['analytics'] = models.Settings.get_settings().analytics
my_path = request.get_full_path()
if request.user is None:
params['sign_in'] = users.create_login_url(my_path)
else:
params['sign_out'] = users.create_logout_url(my_path)
params['star_url'] = '/star'
params['unstar_url'] = '/unstar'
params['inline_draft_url'] = '/inline_draft'
if not template.endswith('.html'):
template += '.html'
type = 'text/html; charset=UTF-8'
ctx = django.template.Context(params)
body = _get_template(template).render(ctx)
return HttpResponse(content = body,
status = status,
content_type= type)
except DeadlineExceededError:
logging.exception('DeadlineExceededError')
return HttpResponse(status=500, content='DeadlineExceededError')
except MemoryError:
logging.exception('MemoryError')
return HttpResponse(status=500, content='MemoryError')
except AssertionError:
logging.exception('AssertionError')
return HttpResponse(status=500, content='AssertionError')
### Form Handling ###
_xsrf_key = None
_xsrf_now = None
_xsrf_cache = {}
def _now():
global _xsrf_now
if _xsrf_now is None:
_xsrf_now = time.time()
return _xsrf_now
def _xsrf_sign(path, when):
global _xsrf_key
if _xsrf_key is None:
_xsrf_key = models.Settings.get_settings().xsrf_key
_xsrf_key = base64.b64decode(_xsrf_key)
user = users.get_current_user()
if user:
user_name = user.email()
else:
user_name = '-'
tok = [user_name, path, str(when)]
xsrf = hmac.new(_xsrf_key, digestmod=hashlib.sha1)
xsrf.update(':'.join(tok))
return base64.b64encode(str(when) + ':' + xsrf.digest())
def _xsrf_check(path, xsrf):
if not xsrf:
return False
try:
when = int(base64.b64decode(xsrf).split(':', 2)[0])
except TypeError:
return False
except ValueError:
return False
except UnicodeEncodeError:
return False
if abs(_now() - when) > MAX_XSRF_WINDOW:
return False
return xsrf == _xsrf_sign(path, when)
class BaseForm(django.forms.Form):
"""A Django form which provides automatic XSRF protection,
assuming it is parsed/displayed by process_form()
"""
# Name of the template the form renders itself as.
#
# Must be replaced by the subclass.
#
_template = None
xsrf = django.forms.CharField(required = False,
widget = django.forms.HiddenInput)
@classmethod
def _init(cls, state):
"""Obtain the initial values for the fields of the form.
Args:
state: state object supplied by the caller of process_form
Returns:
dict of form constructor keywords; at minimum the key
'initial' must be a dict
"""
return {'initial': {}}
def _pre_verify(self, get, post):
"""Gives the form a crack at the raw post data before verification.
If this method returns an HttpResponse object, that will be
returned, and _save will not be called.
"""
return None
def _save(self, cd, state):
"""Processes the form data, typically saving it to the db.
Adding an error to self.errors['fieldname'] will cause
the form to be redisplayed, in case the save routine finds
problems with the submitted data and wants the user to try
and correct them.
Args:
cd: dict of cleaned field values (same as self.cleaned_data)
state: state object supplied by the caller of process_form
"""
raise NotImplementedError()
def process_form(request, form_cls, state, done, params=None):
"""Display (or parse and process) an HTML form.
Args:
request: Django request object
form_cls: class object for a subclass of BaseForm
state: any application state object, to be passed into
the _init and _save methods of BaseForm
done: a callable invoked after _save is successful;
its return value is the result of this function
params: dictional of additional parameters to pass into
the Django template
Returns:
an HttpResponse (or the result of done() if _save was called)
"""
if params is None:
params = {}
def _handle_result(result):
if isinstance(result, HttpResponse):
return result
elif isinstance(result, BaseForm):
params['form'] = result
return respond(request, result._template, params)
if request.method == 'POST':
form = form_cls(request.POST)
if _xsrf_check(request.get_full_path(), request.POST.get('xsrf')):
result = form._pre_verify(request.GET, request.POST)
if result:
return _handle_result(result)
if form.is_valid():
# for form.cleaned_data to exist
result = form._save(form.cleaned_data, state)
if result:
return _handle_result(result)
if form.is_valid():
return done()
else:
if form.is_valid(): # this check forces cleaned_data
i = dict(form.cleaned_data)
i['xsrf'] = xsrf_for(request.get_full_path())
form = form_cls(initial=i)
form._errors = {}
form._errors['xsrf'] = ['Form token timed out. Try again.']
else:
kwargs = form_cls._init(state)
kwargs['initial']['xsrf'] = xsrf_for(request.get_full_path())
form = form_cls(**kwargs)
params['form'] = form
return respond(request, form._template, params)
def xsrf_for(path):
try:
return _xsrf_cache[path]
except KeyError:
pass
r = _xsrf_sign(path, int(_now()))
_xsrf_cache[path] = r
return r
def is_xsrf_ok(request, path=None, xsrf=None):
if path is None:
path = request.get_full_path()
if xsrf is None:
xsrf = request.POST.get('xsrf')
return _xsrf_check(path, xsrf)
def xsrf_required(func):
"""Decorator that requires invocation by HTTP POST only,
and the form must have an 'xsrf' field with a valid
xsrf key (see xsrf_for() to make such keys).
Implies @login_required
"""
def post_wrapper(request, *args, **kwds):
if request.method != 'POST':
return HttpResponse("POST request required.", status=405)
if not is_xsrf_ok(request):
return HttpResponse("Invalid xsrf signature."
" Reload the prior page.", status=405)
return func(request, *args, **kwds)
return login_required(post_wrapper)
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