taiga-back/taiga/base/api/views.py

478 lines
18 KiB
Python

# Copyright (C) 2014-2016 Andrey Antukh <niwi@niwi.nz>
# Copyright (C) 2014-2016 Jesús Espino <jespinog@gmail.com>
# Copyright (C) 2014-2016 David Barragán <bameda@dbarragan.com>
# Copyright (C) 2014-2016 Alejandro Alonso <alejandro.alonso@kaleidos.net>
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# The code is partially taken (and modified) from django rest framework
# that is licensed under the following terms:
#
# Copyright (c) 2011-2014, Tom Christie
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# Redistributions of source code must retain the above copyright notice, this
# list of conditions and the following disclaimer.
# Redistributions in binary form must reproduce the above copyright notice, this
# list of conditions and the following disclaimer in the documentation and/or
# other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
import json
from django.conf import settings
from django.core.exceptions import PermissionDenied
from django.http import Http404, HttpResponse
from django.http.response import HttpResponseBase
from django.views.decorators.csrf import csrf_exempt
from django.views.defaults import server_error
from django.views.generic import View
from django.utils.datastructures import SortedDict
from django.utils.encoding import smart_text
from django.utils.translation import ugettext as _
from .request import Request
from .settings import api_settings
from .utils import formatting
from taiga.base import status
from taiga.base import exceptions
from taiga.base.response import Response
from taiga.base.response import Ok
from taiga.base.response import NotFound
from taiga.base.response import Forbidden
from taiga.base.utils.iterators import as_tuple
def get_view_name(view_cls, suffix=None):
"""
Given a view class, return a textual name to represent the view.
This name is used in the browsable API, and in OPTIONS responses.
This function is the default for the `VIEW_NAME_FUNCTION` setting.
"""
name = view_cls.__name__
name = formatting.remove_trailing_string(name, 'View')
name = formatting.remove_trailing_string(name, 'ViewSet')
name = formatting.camelcase_to_spaces(name)
if suffix:
name += ' ' + suffix
return name
def get_view_description(view_cls, html=False):
"""
Given a view class, return a textual description to represent the view.
This name is used in the browsable API, and in OPTIONS responses.
This function is the default for the `VIEW_DESCRIPTION_FUNCTION` setting.
"""
description = view_cls.__doc__ or ''
description = formatting.dedent(smart_text(description))
if html:
return formatting.markup_description(description)
return description
def exception_handler(exc):
"""
Returns the response that should be used for any given exception.
By default we handle the REST framework `APIException`, and also
Django's builtin `Http404` and `PermissionDenied` exceptions.
Any unhandled exceptions may return `None`, which will cause a 500 error
to be raised.
"""
if isinstance(exc, exceptions.APIException):
headers = {}
if getattr(exc, 'auth_header', None):
headers['WWW-Authenticate'] = exc.auth_header
if getattr(exc, 'wait', None):
headers['X-Throttle-Wait-Seconds'] = '%d' % exc.wait
return Response({'detail': exc.detail},
status=exc.status_code,
headers=headers)
elif isinstance(exc, Http404):
return NotFound({'detail': _('Not found')})
elif isinstance(exc, PermissionDenied):
return Forbidden({'detail': _('Permission denied')})
# Note: Unhandled exceptions will raise a 500 error.
return None
class APIView(View):
# The following policies may be set at either globally, or per-view.
renderer_classes = api_settings.DEFAULT_RENDERER_CLASSES
parser_classes = api_settings.DEFAULT_PARSER_CLASSES
authentication_classes = api_settings.DEFAULT_AUTHENTICATION_CLASSES
throttle_classes = api_settings.DEFAULT_THROTTLE_CLASSES
permission_classes = api_settings.DEFAULT_PERMISSION_CLASSES
content_negotiation_class = api_settings.DEFAULT_CONTENT_NEGOTIATION_CLASS
# Allow dependancy injection of other settings to make testing easier.
settings = api_settings
@classmethod
def as_view(cls, **initkwargs):
"""
Store the original class on the view function.
This allows us to discover information about the view when we do URL
reverse lookups. Used for breadcrumb generation.
"""
view = super(APIView, cls).as_view(**initkwargs)
view.cls = cls
return view
@property
def allowed_methods(self):
"""
Wrap Django's private `_allowed_methods` interface in a public property.
"""
return self._allowed_methods()
@property
def default_response_headers(self):
headers = {
'Allow': ', '.join(self.allowed_methods),
}
if len(self.renderer_classes) > 1:
headers['Vary'] = 'Accept'
return headers
def http_method_not_allowed(self, request, *args, **kwargs):
"""
If `request.method` does not correspond to a handler method,
determine what kind of exception to raise.
"""
raise exceptions.MethodNotAllowed(request.method)
def permission_denied(self, request):
"""
If request is not permitted, determine what kind of exception to raise.
"""
if not request.successful_authenticator:
raise exceptions.NotAuthenticated()
raise exceptions.PermissionDenied()
def throttled(self, request, wait):
"""
If request is throttled, determine what kind of exception to raise.
"""
raise exceptions.Throttled(wait)
def get_authenticate_header(self, request):
"""
If a request is unauthenticated, determine the WWW-Authenticate
header to use for 401 responses, if any.
"""
authenticators = self.get_authenticators()
if authenticators:
return authenticators[0].authenticate_header(request)
def get_parser_context(self, http_request):
"""
Returns a dict that is passed through to Parser.parse(),
as the `parser_context` keyword argument.
"""
# Note: Additionally `request` and `encoding` will also be added
# to the context by the Request object.
return {
'view': self,
'args': getattr(self, 'args', ()),
'kwargs': getattr(self, 'kwargs', {})
}
def get_renderer_context(self):
"""
Returns a dict that is passed through to Renderer.render(),
as the `renderer_context` keyword argument.
"""
# Note: Additionally 'response' will also be added to the context,
# by the Response object.
return {
'view': self,
'args': getattr(self, 'args', ()),
'kwargs': getattr(self, 'kwargs', {}),
'request': getattr(self, 'request', None)
}
def get_view_name(self):
"""
Return the view name, as used in OPTIONS responses and in the
browsable API.
"""
func = self.settings.VIEW_NAME_FUNCTION
return func(self.__class__, getattr(self, 'suffix', None))
def get_view_description(self, html=False):
"""
Return some descriptive text for the view, as used in OPTIONS responses
and in the browsable API.
"""
func = self.settings.VIEW_DESCRIPTION_FUNCTION
return func(self.__class__, html)
# API policy instantiation methods
def get_format_suffix(self, **kwargs):
"""
Determine if the request includes a '.json' style format suffix
"""
if self.settings.FORMAT_SUFFIX_KWARG:
return kwargs.get(self.settings.FORMAT_SUFFIX_KWARG)
def get_renderers(self):
"""
Instantiates and returns the list of renderers that this view can use.
"""
return [renderer() for renderer in self.renderer_classes]
def get_parsers(self):
"""
Instantiates and returns the list of parsers that this view can use.
"""
return [parser() for parser in self.parser_classes]
def get_authenticators(self):
"""
Instantiates and returns the list of authenticators that this view can use.
"""
return [auth() for auth in self.authentication_classes]
@as_tuple
def get_permissions(self):
"""
Instantiates and returns the list of permissions that this view requires.
"""
for permcls in self.permission_classes:
instance = permcls(request=self.request,
view=self)
yield instance
def get_throttles(self):
"""
Instantiates and returns the list of throttles that this view uses.
"""
return [throttle() for throttle in self.throttle_classes]
def get_content_negotiator(self):
"""
Instantiate and return the content negotiation class to use.
"""
if not getattr(self, '_negotiator', None):
self._negotiator = self.content_negotiation_class()
return self._negotiator
# API policy implementation methods
def perform_content_negotiation(self, request, force=False):
"""
Determine which renderer and media type to use render the response.
"""
renderers = self.get_renderers()
conneg = self.get_content_negotiator()
try:
return conneg.select_renderer(request, renderers, self.format_kwarg)
except Exception:
if force:
return (renderers[0], renderers[0].media_type)
raise
def perform_authentication(self, request):
"""
Perform authentication on the incoming request.
Note that if you override this and simply 'pass', then authentication
will instead be performed lazily, the first time either
`request.user` or `request.auth` is accessed.
"""
request.user
def check_permissions(self, request, action:str=None, obj=None):
if action is None:
self.permission_denied(request)
for permission in self.get_permissions():
if not permission.check_permissions(action=action, obj=obj):
self.permission_denied(request)
def check_object_permissions(self, request, obj):
self.check_permissions(request, None, obj)
def check_throttles(self, request):
"""
Check if request should be throttled.
Raises an appropriate exception if the request is throttled.
"""
for throttle in self.get_throttles():
if not throttle.allow_request(request, self):
self.throttled(request, throttle.wait())
# Dispatch methods
def initialize_request(self, request, *args, **kwargs):
"""
Returns the initial request object.
"""
parser_context = self.get_parser_context(request)
return Request(request,
parsers=self.get_parsers(),
authenticators=self.get_authenticators(),
negotiator=self.get_content_negotiator(),
parser_context=parser_context)
def initial(self, request, *args, **kwargs):
"""
Runs anything that needs to occur prior to calling the method handler.
"""
self.format_kwarg = self.get_format_suffix(**kwargs)
# Ensure that the incoming request is permitted
self.perform_authentication(request)
self.check_throttles(request)
# Perform content negotiation and store the accepted info on the request
neg = self.perform_content_negotiation(request)
request.accepted_renderer, request.accepted_media_type = neg
def finalize_response(self, request, response, *args, **kwargs):
"""
Returns the final response object.
"""
# Make the error obvious if a proper response is not returned
assert isinstance(response, HttpResponseBase), ('Expected a `Response`, `HttpResponse` or '
'`HttpStreamingResponse` to be returned from the view, '
'but received a `%s`' % type(response))
if isinstance(response, Response):
if not getattr(request, 'accepted_renderer', None):
neg = self.perform_content_negotiation(request, force=True)
request.accepted_renderer, request.accepted_media_type = neg
response.accepted_renderer = request.accepted_renderer
response.accepted_media_type = request.accepted_media_type
response.renderer_context = self.get_renderer_context()
for key, value in self.headers.items():
response[key] = value
return response
def handle_exception(self, exc):
"""
Handle any exception that occurs, by returning an appropriate response,
or re-raising the error.
"""
if isinstance(exc, (exceptions.NotAuthenticated,
exceptions.AuthenticationFailed)):
# WWW-Authenticate header for 401 responses, else coerce to 403
auth_header = self.get_authenticate_header(self.request)
if auth_header:
exc.auth_header = auth_header
else:
exc.status_code = status.HTTP_403_FORBIDDEN
response = self.settings.EXCEPTION_HANDLER(exc)
if response is None:
raise
response.exception = True
return response
# Note: session based authentication is explicitly CSRF validated,
# all other authentication is CSRF exempt.
@csrf_exempt
def dispatch(self, request, *args, **kwargs):
"""
`.dispatch()` is pretty much the same as Django's regular dispatch,
but with extra hooks for startup, finalize, and exception handling.
"""
self.args = args
self.kwargs = kwargs
request = self.initialize_request(request, *args, **kwargs)
self.request = request
self.headers = self.default_response_headers
try:
self.initial(request, *args, **kwargs)
# Get the appropriate handler method
if request.method.lower() in self.http_method_names:
handler = getattr(self, request.method.lower(),
self.http_method_not_allowed)
else:
handler = self.http_method_not_allowed
response = handler(request, *args, **kwargs)
except Exception as exc:
response = self.handle_exception(exc)
self.response = self.finalize_response(request, response, *args, **kwargs)
return self.response
def options(self, request, *args, **kwargs):
"""
Handler method for HTTP 'OPTIONS' request.
We may as well implement this as Django will otherwise provide
a less useful default implementation.
"""
return Ok(self.metadata(request))
def metadata(self, request):
"""
Return a dictionary of metadata about the view.
Used to return responses for OPTIONS requests.
"""
# By default we can't provide any form-like information, however the
# generic views override this implementation and add additional
# information for POST and PUT methods, based on the serializer.
ret = SortedDict()
ret['name'] = self.get_view_name()
ret['description'] = self.get_view_description()
ret['renders'] = [renderer.media_type for renderer in self.renderer_classes]
ret['parses'] = [parser.media_type for parser in self.parser_classes]
return ret
def api_server_error(request, *args, **kwargs):
if settings.DEBUG is False and request.META.get('CONTENT_TYPE', None) == "application/json":
return HttpResponse(json.dumps({"error": _("Server application error")}),
status=status.HTTP_500_INTERNAL_SERVER_ERROR)
return server_error(request, *args, **kwargs)